src/resolve/resolved-dns-question.c

   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-question.h"
  23 #include "resolved-dns-domain.h"
  24
  25 DnsQuestion *dns_question_new(unsigned n) {
  26         DnsQuestion *q;
  27
  28         assert(n > 0);
  29
  30         q = malloc0(offsetof(DnsQuestion, keys) + sizeof(DnsResourceKey*) * n);
  31         if (!q)
  32                 return NULL;
  33
  34         q->n_ref = 1;
  35         q->n_allocated = n;
  36
  37         return q;
  38 }
  39
  40 DnsQuestion *dns_question_ref(DnsQuestion *q) {
  41         if (!q)
  42                 return NULL;
  43
  44         assert(q->n_ref > 0);
  45         q->n_ref++;
  46         return q;
  47 }
  48
  49 DnsQuestion *dns_question_unref(DnsQuestion *q) {
  50         if (!q)
  51                 return NULL;
  52
  53         assert(q->n_ref > 0);
  54
  55         if (q->n_ref == 1) {
  56                 unsigned i;
  57
  58                 for (i = 0; i < q->n_keys; i++)
  59                         dns_resource_key_unref(q->keys[i]);
  60                 free(q);
  61         } else
  62                 q->n_ref--;
  63
  64         return  NULL;
  65 }
  66
  67 int dns_question_add(DnsQuestion *q, DnsResourceKey *key) {
  68         unsigned i;
  69         int r;
  70
  71         assert(q);
  72         assert(key);
  73
  74         for (i = 0; i < q->n_keys; i++) {
  75                 r = dns_resource_key_equal(q->keys[i], key);
  76                 if (r < 0)
  77                         return r;
  78                 if (r > 0)
  79                         return 0;
  80         }
  81
  82         if (q->n_keys >= q->n_allocated)
  83                 return -ENOSPC;
  84
  85         q->keys[q->n_keys++] = dns_resource_key_ref(key);
  86         return 0;
  87 }
  88
  89 int dns_question_matches_rr(DnsQuestion *q, DnsResourceRecord *rr) {
  90         unsigned i;
  91         int r;
  92
  93         assert(q);
  94         assert(rr);
  95
  96         for (i = 0; i < q->n_keys; i++) {
  97                 r = dns_resource_key_match_rr(q->keys[i], rr);
  98                 if (r != 0)
  99                         return r;
 100         }
 101
 102         return 0;
 103 }
 104
 105 int dns_question_matches_cname(DnsQuestion *q, DnsResourceRecord *rr) {
 106         unsigned i;
 107         int r;
 108
 109         assert(q);
 110         assert(rr);
 111
 112         for (i = 0; i < q->n_keys; i++) {
 113                 r = dns_resource_key_match_cname(q->keys[i], rr);
 114                 if (r != 0)
 115                         return r;
 116         }
 117
 118         return 1;
 119 }
 120
 121 int dns_question_is_valid(DnsQuestion *q) {
 122         const char *name;
 123         unsigned i;
 124         int r;
 125
 126         assert(q);
 127
 128         if (q->n_keys <= 0)
 129                 return 0;
 130
 131         if (q->n_keys > 65535)
 132                 return 0;
 133
 134         name = DNS_RESOURCE_KEY_NAME(q->keys[0]);
 135         if (!name)
 136                 return 0;
 137
 138         /* Check that all keys in this question bear the same name */
 139         for (i = 1; i < q->n_keys; i++) {
 140                 r = dns_name_equal(DNS_RESOURCE_KEY_NAME(q->keys[i]), name);
 141                 if (r <= 0)
 142                         return r;
 143         }
 144
 145         return 1;
 146 }
 147
 148 int dns_question_is_superset(DnsQuestion *q, DnsQuestion *other) {
 149         unsigned j;
 150         int r;
 151
 152         assert(q);
 153         assert(other);
 154
 155         /* Checks if all keys in "other" are also contained in "q" */
 156
 157         for (j = 0; j < other->n_keys; j++) {
 158                 DnsResourceKey *b = other->keys[j];
 159                 bool found = false;
 160                 unsigned i;
 161
 162                 for (i = 0; i < q->n_keys; i++) {
 163                         DnsResourceKey *a = q->keys[i];
 164
 165                         r = dns_name_equal(DNS_RESOURCE_KEY_NAME(a), DNS_RESOURCE_KEY_NAME(b));
 166                         if (r < 0)
 167                                 return r;
 168
 169                         if (r == 0)
 170                                 continue;
 171
 172                         if (a->class != b->class && a->class != DNS_CLASS_ANY)
 173                                 continue;
 174
 175                         if (a->type != b->type && a->type != DNS_TYPE_ANY)
 176                                 continue;
 177
 178                         found = true;
 179                         break;
 180                 }
 181
 182                 if (!found)
 183                         return 0;
 184         }
 185
 186         return 1;
 187 }
 188
 189 int dns_question_cname_redirect(DnsQuestion *q, const char *name, DnsQuestion **ret) {
 190         _cleanup_(dns_question_unrefp) DnsQuestion *n = NULL;
 191         bool same = true;
 192         unsigned i;
 193         int r;
 194
 195         assert(q);
 196         assert(name);
 197         assert(ret);
 198
 199         for (i = 0; i < q->n_keys; i++) {
 200                 r = dns_name_equal(DNS_RESOURCE_KEY_NAME(q->keys[i]), name);
 201                 if (r < 0)
 202                         return r;
 203
 204                 if (r == 0) {
 205                         same = false;
 206                         break;
 207                 }
 208         }
 209
 210         if (same) {
 211                 /* Shortcut, the names are already right */
 212                 *ret = dns_question_ref(q);
 213                 return 0;
 214         }
 215
 216         n = dns_question_new(q->n_keys);
 217         if (!n)
 218                 return -ENOMEM;
 219
 220         /* Create a new question, and patch in the new name */
 221         for (n->n_keys = 0; n->n_keys < q->n_keys; n->n_keys++) {
 222                 _cleanup_(dns_resource_key_unrefp) DnsResourceKey *k = NULL;
 223
 224                 k = dns_resource_key_new(q->keys[i]->class, q->keys[i]->type, name);
 225                 if (!k)
 226                         return -ENOMEM;
 227
 228                 r = dns_question_add(n, k);
 229                 if (r < 0)
 230                         return r;
 231         }
 232
 233         *ret = n;
 234         n = NULL;
 235
 236         return 1;
 237 }
 238
 239 int dns_question_endswith(DnsQuestion *q, const char *suffix) {
 240         unsigned i;
 241
 242         assert(q);
 243         assert(suffix);
 244
 245         for (i = 0; i < q->n_keys; i++) {
 246                 int k;
 247
 248                 k = dns_name_endswith(DNS_RESOURCE_KEY_NAME(q->keys[i]), suffix);
 249                 if (k <= 0)
 250                         return k;
 251         }
 252
 253         return 1;
 254 }
 255
 256 int dns_question_extract_reverse_address(DnsQuestion *q, int *family, union in_addr_union *address) {
 257         unsigned i;
 258
 259         assert(q);
 260         assert(family);
 261         assert(address);
 262
 263         for (i = 0; i < q->n_keys; i++) {
 264                 int k;
 265
 266                 k = dns_name_address(DNS_RESOURCE_KEY_NAME(q->keys[i]), family, address);
 267                 if (k != 0)
 268                         return k;
 269         }
 270
 271         return 0;
 272 }