src/resolve/resolved-dns-zone.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 "list.h"
  23
  24 #include "resolved-dns-zone.h"
  25 #include "resolved-dns-domain.h"
  26 #include "resolved-dns-packet.h"
  27
  28 /* Never allow more than 1K entries */
  29 #define ZONE_MAX 1024
  30
  31 typedef struct DnsZoneItem DnsZoneItem;
  32
  33 struct DnsZoneItem {
  34         DnsResourceRecord *rr;
  35         bool verified;
  36         LIST_FIELDS(DnsZoneItem, by_key);
  37         LIST_FIELDS(DnsZoneItem, by_name);
  38 };
  39
  40 static void dns_zone_item_free(DnsZoneItem *i) {
  41         if (!i)
  42                 return;
  43
  44         dns_resource_record_unref(i->rr);
  45         free(i);
  46 }
  47
  48 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsZoneItem*, dns_zone_item_free);
  49
  50 static void dns_zone_item_remove_and_free(DnsZone *z, DnsZoneItem *i) {
  51         DnsZoneItem *first;
  52
  53         assert(z);
  54
  55         if (!i)
  56                 return;
  57
  58         first = hashmap_get(z->by_key, i->rr->key);
  59         LIST_REMOVE(by_key, first, i);
  60         if (first)
  61                 assert_se(hashmap_replace(z->by_key, first->rr->key, first) >= 0);
  62         else
  63                 hashmap_remove(z->by_key, i->rr->key);
  64
  65         first = hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(i->rr->key));
  66         LIST_REMOVE(by_name, first, i);
  67         if (first)
  68                 assert_se(hashmap_replace(z->by_name, DNS_RESOURCE_KEY_NAME(first->rr->key), first) >= 0);
  69         else
  70                 hashmap_remove(z->by_name, DNS_RESOURCE_KEY_NAME(i->rr->key));
  71
  72         dns_zone_item_free(i);
  73 }
  74
  75 void dns_zone_flush(DnsZone *z) {
  76         DnsZoneItem *i;
  77
  78         assert(z);
  79
  80         while ((i = hashmap_first(z->by_key)))
  81                 dns_zone_item_remove_and_free(z, i);
  82
  83         assert(hashmap_size(z->by_key) == 0);
  84         assert(hashmap_size(z->by_name) == 0);
  85
  86         hashmap_free(z->by_key);
  87         z->by_key = NULL;
  88
  89         hashmap_free(z->by_name);
  90         z->by_name = NULL;
  91 }
  92
  93 static DnsZoneItem* dns_zone_get(DnsZone *z, DnsResourceRecord *rr) {
  94         DnsZoneItem *i;
  95
  96         assert(z);
  97         assert(rr);
  98
  99         LIST_FOREACH(by_key, i, hashmap_get(z->by_key, rr->key))
 100                 if (dns_resource_record_equal(i->rr, rr))
 101                         return i;
 102
 103         return NULL;
 104 }
 105
 106 void dns_zone_remove_rr(DnsZone *z, DnsResourceRecord *rr) {
 107         DnsZoneItem *i;
 108
 109         assert(z);
 110         assert(rr);
 111
 112         i = dns_zone_get(z, rr);
 113         if (i)
 114                 dns_zone_item_remove_and_free(z, i);
 115 }
 116
 117 static int dns_zone_init(DnsZone *z) {
 118         int r;
 119
 120         assert(z);
 121
 122         r = hashmap_ensure_allocated(&z->by_key, dns_resource_key_hash_func, dns_resource_key_compare_func);
 123         if (r < 0)
 124                 return r;
 125
 126         r = hashmap_ensure_allocated(&z->by_name, dns_name_hash_func, dns_name_compare_func);
 127         if (r < 0)
 128                 return r;
 129
 130         return 0;
 131 }
 132
 133 static int dns_zone_link_item(DnsZone *z, DnsZoneItem *i) {
 134         DnsZoneItem *first;
 135         int r;
 136
 137         first = hashmap_get(z->by_key, i->rr->key);
 138         if (first) {
 139                 LIST_PREPEND(by_key, first, i);
 140                 assert_se(hashmap_replace(z->by_key, first->rr->key, first) >= 0);
 141         } else {
 142                 r = hashmap_put(z->by_key, i->rr->key, i);
 143                 if (r < 0)
 144                         return r;
 145         }
 146
 147         first = hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(i->rr->key));
 148         if (first) {
 149                 LIST_PREPEND(by_name, first, i);
 150                 assert_se(hashmap_replace(z->by_name, DNS_RESOURCE_KEY_NAME(first->rr->key), first) >= 0);
 151         } else {
 152                 r = hashmap_put(z->by_name, DNS_RESOURCE_KEY_NAME(i->rr->key), i);
 153                 if (r < 0)
 154                         return r;
 155         }
 156
 157         return 0;
 158 }
 159
 160 int dns_zone_put(DnsZone *z, DnsResourceRecord *rr) {
 161         _cleanup_(dns_zone_item_freep) DnsZoneItem *i = NULL;
 162         DnsZoneItem *existing;
 163         int r;
 164
 165         assert(z);
 166         assert(rr);
 167
 168         if (rr->key->class == DNS_CLASS_ANY)
 169                 return -EINVAL;
 170         if (rr->key->type == DNS_TYPE_ANY)
 171                 return -EINVAL;
 172
 173         existing = dns_zone_get(z, rr);
 174         if (existing)
 175                 return 0;
 176
 177         r = dns_zone_init(z);
 178         if (r < 0)
 179                 return r;
 180
 181         i = new0(DnsZoneItem, 1);
 182         if (!i)
 183                 return -ENOMEM;
 184
 185         i->rr = dns_resource_record_ref(rr);
 186
 187         r = dns_zone_link_item(z, i);
 188         if (r < 0)
 189                 return r;
 190
 191         i = NULL;
 192         return 0;
 193 }
 194
 195 int dns_zone_lookup(DnsZone *z, DnsQuestion *q, DnsAnswer **ret) {
 196         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
 197         bool has_other_rrs = false;
 198         unsigned i, n = 0;
 199         int r;
 200
 201         assert(z);
 202         assert(q);
 203         assert(ret);
 204
 205         if (q->n_keys <= 0) {
 206                 *ret = NULL;
 207                 return 0;
 208         }
 209
 210         for (i = 0; i < q->n_keys; i++) {
 211                 DnsZoneItem *j;
 212
 213                 if (q->keys[i]->type == DNS_TYPE_ANY ||
 214                     q->keys[i]->class == DNS_CLASS_ANY) {
 215                         int k;
 216
 217                         /* If this is a generic match, then we have to
 218                          * go through the list by the name and look
 219                          * for everything manually */
 220
 221                         j = hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(q->keys[i]));
 222                         LIST_FOREACH(by_name, j, j) {
 223                                 has_other_rrs = true;
 224
 225                                 k = dns_resource_key_match_rr(q->keys[i], j->rr);
 226                                 if (k < 0)
 227                                         return k;
 228                                 if (k == 0)
 229                                         continue;
 230
 231                                 n++;
 232                         }
 233
 234                 } else {
 235                         j = hashmap_get(z->by_key, q->keys[i]);
 236                         if (!j) {
 237                                 if (hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(q->keys[i])))
 238                                         has_other_rrs = true;
 239
 240                                 continue;
 241                         }
 242
 243                         LIST_FOREACH(by_key, j, j)
 244                                 n++;
 245                 }
 246         }
 247
 248         if (n <= 0) {
 249                 *ret = NULL;
 250                 return has_other_rrs;
 251         }
 252
 253         answer = dns_answer_new(n);
 254         if (!answer)
 255                 return -ENOMEM;
 256
 257         for (i = 0; i < q->n_keys; i++) {
 258                 DnsZoneItem *j;
 259
 260                 if (q->keys[i]->type == DNS_TYPE_ANY ||
 261                     q->keys[i]->class == DNS_CLASS_ANY) {
 262                         int k;
 263
 264                         j = hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(q->keys[i]));
 265                         LIST_FOREACH(by_name, j, j) {
 266                                 k = dns_resource_key_match_rr(q->keys[i], j->rr);
 267                                 if (k < 0)
 268                                         return k;
 269                                 if (k == 0)
 270                                         continue;
 271
 272                                 r = dns_answer_add(answer, j->rr);
 273                                 if (r < 0)
 274                                         return r;
 275                         }
 276                 } else {
 277
 278                         j = hashmap_get(z->by_key, q->keys[i]);
 279                         LIST_FOREACH(by_key, j, j) {
 280                                 r = dns_answer_add(answer, j->rr);
 281                                 if (r < 0)
 282                                         return r;
 283                         }
 284                 }
 285         }
 286
 287         *ret = answer;
 288         answer = NULL;
 289
 290         return 1;
 291 }