xref: /openbsd/usr.bin/dig/lib/dns/rdata/in_1/a6_38.c (revision d415bd75)
1 /*
2  * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
3  *
4  * Permission to use, copy, modify, and/or distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
9  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
10  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
11  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
12  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
13  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
14  * PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /* $Id: a6_38.c,v 1.14 2020/09/14 08:40:44 florian Exp $ */
18 
19 /* RFC2874 */
20 
21 #ifndef RDATA_IN_1_A6_28_C
22 #define RDATA_IN_1_A6_28_C
23 
24 static inline isc_result_t
25 totext_in_a6(ARGS_TOTEXT) {
26 	isc_region_t sr, ar;
27 	unsigned char addr[16];
28 	unsigned char prefixlen;
29 	unsigned char octets;
30 	unsigned char mask;
31 	char buf[sizeof("128")];
32 	dns_name_t name;
33 	dns_name_t prefix;
34 	int sub;
35 
36 	REQUIRE(rdata->type == dns_rdatatype_a6);
37 	REQUIRE(rdata->rdclass == dns_rdataclass_in);
38 	REQUIRE(rdata->length != 0);
39 
40 	dns_rdata_toregion(rdata, &sr);
41 	prefixlen = sr.base[0];
42 	INSIST(prefixlen <= 128);
43 	isc_region_consume(&sr, 1);
44 	snprintf(buf, sizeof(buf), "%u", prefixlen);
45 	RETERR(isc_str_tobuffer(buf, target));
46 	RETERR(isc_str_tobuffer(" ", target));
47 
48 	if (prefixlen != 128) {
49 		octets = prefixlen/8;
50 		memset(addr, 0, sizeof(addr));
51 		memmove(&addr[octets], sr.base, 16 - octets);
52 		mask = 0xff >> (prefixlen % 8);
53 		addr[octets] &= mask;
54 		ar.base = addr;
55 		ar.length = sizeof(addr);
56 		RETERR(inet_totext(AF_INET6, &ar, target));
57 		isc_region_consume(&sr, 16 - octets);
58 	}
59 
60 	if (prefixlen == 0)
61 		return (ISC_R_SUCCESS);
62 
63 	RETERR(isc_str_tobuffer(" ", target));
64 	dns_name_init(&name, NULL);
65 	dns_name_init(&prefix, NULL);
66 	dns_name_fromregion(&name, &sr);
67 	sub = name_prefix(&name, tctx->origin, &prefix);
68 	return (dns_name_totext(&prefix, sub, target));
69 }
70 
71 static inline isc_result_t
72 fromwire_in_a6(ARGS_FROMWIRE) {
73 	isc_region_t sr;
74 	unsigned char prefixlen;
75 	unsigned char octets;
76 	unsigned char mask;
77 	dns_name_t name;
78 
79 	REQUIRE(type == dns_rdatatype_a6);
80 	REQUIRE(rdclass == dns_rdataclass_in);
81 
82 	UNUSED(type);
83 	UNUSED(rdclass);
84 
85 	dns_decompress_setmethods(dctx, DNS_COMPRESS_NONE);
86 
87 	isc_buffer_activeregion(source, &sr);
88 	/*
89 	 * Prefix length.
90 	 */
91 	if (sr.length < 1)
92 		return (ISC_R_UNEXPECTEDEND);
93 	prefixlen = sr.base[0];
94 	if (prefixlen > 128)
95 		return (ISC_R_RANGE);
96 	isc_region_consume(&sr, 1);
97 	RETERR(isc_mem_tobuffer(target, &prefixlen, 1));
98 	isc_buffer_forward(source, 1);
99 
100 	/*
101 	 * Suffix.
102 	 */
103 	if (prefixlen != 128) {
104 		octets = 16 - prefixlen / 8;
105 		if (sr.length < octets)
106 			return (ISC_R_UNEXPECTEDEND);
107 		mask = 0xff >> (prefixlen % 8);
108 		sr.base[0] &= mask;	/* Ensure pad bits are zero. */
109 		RETERR(isc_mem_tobuffer(target, sr.base, octets));
110 		isc_buffer_forward(source, octets);
111 	}
112 
113 	if (prefixlen == 0)
114 		return (ISC_R_SUCCESS);
115 
116 	dns_name_init(&name, NULL);
117 	return (dns_name_fromwire(&name, source, dctx, options, target));
118 }
119 
120 static inline isc_result_t
121 towire_in_a6(ARGS_TOWIRE) {
122 	isc_region_t sr;
123 	dns_name_t name;
124 	dns_offsets_t offsets;
125 	unsigned char prefixlen;
126 	unsigned char octets;
127 
128 	REQUIRE(rdata->type == dns_rdatatype_a6);
129 	REQUIRE(rdata->rdclass == dns_rdataclass_in);
130 	REQUIRE(rdata->length != 0);
131 
132 	dns_compress_setmethods(cctx, DNS_COMPRESS_NONE);
133 	dns_rdata_toregion(rdata, &sr);
134 	prefixlen = sr.base[0];
135 	INSIST(prefixlen <= 128);
136 
137 	octets = 1 + 16 - prefixlen / 8;
138 	RETERR(isc_mem_tobuffer(target, sr.base, octets));
139 	isc_region_consume(&sr, octets);
140 
141 	if (prefixlen == 0)
142 		return (ISC_R_SUCCESS);
143 
144 	dns_name_init(&name, offsets);
145 	dns_name_fromregion(&name, &sr);
146 	return (dns_name_towire(&name, cctx, target));
147 }
148 
149 #endif	/* RDATA_IN_1_A6_38_C */
150