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         existing = dns_zone_get(z, rr);
 169         if (existing)
 170                 return 0;
 171
 172         r = dns_zone_init(z);
 173         if (r < 0)
 174                 return r;
 175
 176         i = new0(DnsZoneItem, 1);
 177         if (!i)
 178                 return -ENOMEM;
 179
 180         i->rr = dns_resource_record_ref(rr);
 181
 182         r = dns_zone_link_item(z, i);
 183         if (r < 0)
 184                 return r;
 185
 186         i = NULL;
 187         return 0;
 188 }
 189
 190 int dns_zone_lookup(DnsZone *z, DnsQuestion *q, DnsAnswer **ret) {
 191         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
 192         int r;
 193         unsigned i, n = 0;
 194         bool has_other_rrs = false;
 195
 196         assert(z);
 197         assert(q);
 198         assert(ret);
 199
 200         if (q->n_keys <= 0) {
 201                 *ret = NULL;
 202                 return 0;
 203         }
 204
 205         for (i = 0; i < q->n_keys; i++) {
 206                 DnsZoneItem *j;
 207
 208                 j = hashmap_get(z->by_key, q->keys[i]);
 209                 if (!j) {
 210                         if (hashmap_get(z->by_name, DNS_RESOURCE_KEY_NAME(q->keys[i])))
 211                                 has_other_rrs = true;
 212
 213                         continue;
 214                 }
 215
 216                 LIST_FOREACH(by_name, j, j)
 217                         n++;
 218         }
 219
 220         if (n <= 0) {
 221                 *ret = NULL;
 222                 return has_other_rrs;
 223         }
 224
 225         answer = dns_answer_new(n);
 226         if (!answer)
 227                 return -ENOMEM;
 228
 229         for (i = 0; i < q->n_keys; i++) {
 230                 DnsZoneItem *j;
 231
 232                 j = hashmap_get(z->by_key, q->keys[i]);
 233                 LIST_FOREACH(by_key, j, j) {
 234                         r = dns_answer_add(answer, j->rr);
 235                         if (r < 0)
 236                                 return r;
 237                 }
 238         }
 239
 240         *ret = answer;
 241         answer = NULL;
 242
 243         return 1;
 244 }