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faa133f3 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2014 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include "resolved-dns-answer.h" | |
4ad7f276 | 23 | #include "dns-domain.h" |
faa133f3 LP |
24 | |
25 | DnsAnswer *dns_answer_new(unsigned n) { | |
26 | DnsAnswer *a; | |
27 | ||
faa133f3 LP |
28 | a = malloc0(offsetof(DnsAnswer, rrs) + sizeof(DnsResourceRecord*) * n); |
29 | if (!a) | |
30 | return NULL; | |
31 | ||
32 | a->n_ref = 1; | |
33 | a->n_allocated = n; | |
34 | ||
35 | return a; | |
36 | } | |
37 | ||
38 | DnsAnswer *dns_answer_ref(DnsAnswer *a) { | |
39 | if (!a) | |
40 | return NULL; | |
41 | ||
42 | assert(a->n_ref > 0); | |
43 | a->n_ref++; | |
44 | return a; | |
45 | } | |
46 | ||
47 | DnsAnswer *dns_answer_unref(DnsAnswer *a) { | |
48 | if (!a) | |
49 | return NULL; | |
50 | ||
51 | assert(a->n_ref > 0); | |
52 | ||
53 | if (a->n_ref == 1) { | |
54 | unsigned i; | |
55 | ||
56 | for (i = 0; i < a->n_rrs; i++) | |
57 | dns_resource_record_unref(a->rrs[i]); | |
58 | ||
59 | free(a); | |
60 | } else | |
61 | a->n_ref--; | |
62 | ||
63 | return NULL; | |
64 | } | |
65 | ||
66 | int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr) { | |
7e8e0422 LP |
67 | unsigned i; |
68 | int r; | |
69 | ||
faa133f3 LP |
70 | assert(a); |
71 | assert(rr); | |
72 | ||
7e8e0422 LP |
73 | for (i = 0; i < a->n_rrs; i++) { |
74 | r = dns_resource_record_equal(a->rrs[i], rr); | |
75 | if (r < 0) | |
76 | return r; | |
77 | if (r > 0) { | |
78 | /* Entry already exists, keep the entry with | |
79 | * the higher RR, or the one with TTL 0 */ | |
80 | ||
81 | if (rr->ttl == 0 || (rr->ttl > a->rrs[i]->ttl && a->rrs[i]->ttl != 0)) { | |
82 | dns_resource_record_ref(rr); | |
83 | dns_resource_record_unref(a->rrs[i]); | |
84 | a->rrs[i] = rr; | |
85 | } | |
86 | ||
87 | return 0; | |
88 | } | |
89 | } | |
90 | ||
faa133f3 LP |
91 | if (a->n_rrs >= a->n_allocated) |
92 | return -ENOSPC; | |
93 | ||
94 | a->rrs[a->n_rrs++] = dns_resource_record_ref(rr); | |
7e8e0422 LP |
95 | return 1; |
96 | } | |
97 | ||
57f5ad31 | 98 | int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl) { |
8bf52d3d LP |
99 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *soa = NULL; |
100 | ||
101 | soa = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SOA, name); | |
102 | if (!soa) | |
103 | return -ENOMEM; | |
104 | ||
57f5ad31 LP |
105 | soa->ttl = ttl; |
106 | ||
8bf52d3d LP |
107 | soa->soa.mname = strdup(name); |
108 | if (!soa->soa.mname) | |
109 | return -ENOMEM; | |
110 | ||
111 | soa->soa.rname = strappend("root.", name); | |
112 | if (!soa->soa.rname) | |
113 | return -ENOMEM; | |
114 | ||
115 | soa->soa.serial = 1; | |
116 | soa->soa.refresh = 1; | |
117 | soa->soa.retry = 1; | |
118 | soa->soa.expire = 1; | |
57f5ad31 | 119 | soa->soa.minimum = ttl; |
8bf52d3d LP |
120 | |
121 | return dns_answer_add(a, soa); | |
122 | } | |
123 | ||
7e8e0422 LP |
124 | int dns_answer_contains(DnsAnswer *a, DnsResourceKey *key) { |
125 | unsigned i; | |
126 | int r; | |
127 | ||
128 | assert(a); | |
129 | assert(key); | |
130 | ||
131 | for (i = 0; i < a->n_rrs; i++) { | |
132 | r = dns_resource_key_match_rr(key, a->rrs[i]); | |
133 | if (r < 0) | |
134 | return r; | |
135 | if (r > 0) | |
136 | return 1; | |
137 | } | |
138 | ||
139 | return 0; | |
140 | } | |
141 | ||
142 | int dns_answer_find_soa(DnsAnswer *a, DnsResourceKey *key, DnsResourceRecord **ret) { | |
143 | unsigned i; | |
144 | ||
145 | assert(a); | |
146 | assert(key); | |
147 | assert(ret); | |
148 | ||
0f05c387 LP |
149 | /* For a SOA record we can never find a matching SOA record */ |
150 | if (key->type == DNS_TYPE_SOA) | |
151 | return 0; | |
152 | ||
7e8e0422 LP |
153 | for (i = 0; i < a->n_rrs; i++) { |
154 | ||
155 | if (a->rrs[i]->key->class != DNS_CLASS_IN) | |
156 | continue; | |
157 | ||
158 | if (a->rrs[i]->key->type != DNS_TYPE_SOA) | |
159 | continue; | |
160 | ||
161 | if (dns_name_endswith(DNS_RESOURCE_KEY_NAME(key), DNS_RESOURCE_KEY_NAME(a->rrs[i]->key))) { | |
162 | *ret = a->rrs[i]; | |
163 | return 1; | |
164 | } | |
165 | } | |
166 | ||
faa133f3 LP |
167 | return 0; |
168 | } | |
934e9b10 LP |
169 | |
170 | DnsAnswer *dns_answer_merge(DnsAnswer *a, DnsAnswer *b) { | |
171 | _cleanup_(dns_answer_unrefp) DnsAnswer *ret = NULL; | |
172 | DnsAnswer *k; | |
173 | unsigned i; | |
174 | int r; | |
175 | ||
176 | if (a && (!b || b->n_rrs <= 0)) | |
177 | return dns_answer_ref(a); | |
178 | if ((!a || a->n_rrs <= 0) && b) | |
179 | return dns_answer_ref(b); | |
180 | ||
181 | ret = dns_answer_new((a ? a->n_rrs : 0) + (b ? b->n_rrs : 0)); | |
182 | if (!ret) | |
183 | return NULL; | |
184 | ||
185 | if (a) { | |
186 | for (i = 0; i < a->n_rrs; i++) { | |
187 | r = dns_answer_add(ret, a->rrs[i]); | |
188 | if (r < 0) | |
189 | return NULL; | |
190 | } | |
191 | } | |
192 | ||
193 | if (b) { | |
194 | for (i = 0; i < b->n_rrs; i++) { | |
195 | r = dns_answer_add(ret, b->rrs[i]); | |
196 | if (r < 0) | |
197 | return NULL; | |
198 | } | |
199 | } | |
200 | ||
201 | k = ret; | |
202 | ret = NULL; | |
203 | ||
204 | return k; | |
205 | } | |
af93291c LP |
206 | |
207 | void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local) { | |
208 | DnsResourceRecord **rrs; | |
209 | unsigned i, start, end; | |
210 | assert(a); | |
211 | ||
212 | if (a->n_rrs <= 1) | |
213 | return; | |
214 | ||
215 | start = 0; | |
216 | end = a->n_rrs-1; | |
217 | ||
218 | /* RFC 4795, Section 2.6 suggests we should order entries | |
219 | * depending on whether the sender is a link-local address. */ | |
220 | ||
221 | rrs = newa(DnsResourceRecord*, a->n_rrs); | |
222 | for (i = 0; i < a->n_rrs; i++) { | |
223 | ||
224 | if (a->rrs[i]->key->class == DNS_CLASS_IN && | |
225 | ((a->rrs[i]->key->type == DNS_TYPE_A && in_addr_is_link_local(AF_INET, (union in_addr_union*) &a->rrs[i]->a.in_addr) != prefer_link_local) || | |
226 | (a->rrs[i]->key->type == DNS_TYPE_AAAA && in_addr_is_link_local(AF_INET6, (union in_addr_union*) &a->rrs[i]->aaaa.in6_addr) != prefer_link_local))) | |
227 | /* Order address records that are are not preferred to the end of the array */ | |
228 | rrs[end--] = a->rrs[i]; | |
229 | else | |
230 | /* Order all other records to the beginning of the array */ | |
231 | rrs[start++] = a->rrs[i]; | |
232 | } | |
233 | ||
234 | assert(start == end+1); | |
235 | memcpy(a->rrs, rrs, sizeof(DnsResourceRecord*) * a->n_rrs); | |
236 | } |