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         int r;
 198         unsigned i, n = 0;
 199         bool has_other_rrs = false;
 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                 j = hashmap_get(z->by_key, q->keys[i]);
 214                 if (!j) {
 215                         if (hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(q->keys[i])))
 216                                 has_other_rrs = true;
 217
 218                         continue;
 219                 }
 220
 221                 LIST_FOREACH(by_name, j, j)
 222                         n++;
 223         }
 224
 225         if (n <= 0) {
 226                 *ret = NULL;
 227                 return has_other_rrs;
 228         }
 229
 230         answer = dns_answer_new(n);
 231         if (!answer)
 232                 return -ENOMEM;
 233
 234         for (i = 0; i < q->n_keys; i++) {
 235                 DnsZoneItem *j;
 236
 237                 j = hashmap_get(z->by_key, q->keys[i]);
 238                 LIST_FOREACH(by_key, j, j) {
 239                         r = dns_answer_add(answer, j->rr);
 240                         if (r < 0)
 241                                 return r;
 242                 }
 243         }
 244
 245         *ret = answer;
 246         answer = NULL;
 247
 248         return 1;
 249 }