src/IOHandler/IODNSLookup.c

   1 /* IODNSLookup.c - IOMultiplexer
   2  * Copyright (C) 2014  Philipp Kreil (pk910)
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  16  */
  17 #define _IOHandler_internals
  18 #include "IOInternal.h"
  19 #include "IOHandler.h"
  20 #include "IODNSLookup.h"
  21 #include "IOLog.h"
  22 #include "IOSockets.h"
  23
  24 #include <string.h>
  25
  26 struct _IODNSQuery *iodnsquery_first = NULL;
  27 struct _IODNSQuery *iodnsquery_last = NULL;
  28
  29 struct IODNSEngine *dnsengine = NULL;
  30
  31 static void iodns_init_engine() {
  32         if(dnsengine)
  33                 return;
  34         //try DNS engines
  35         if(dnsengine_cares.init && dnsengine_cares.init())
  36                 dnsengine = &dnsengine_cares;
  37         else if(dnsengine_default.init && dnsengine_default.init())
  38                 dnsengine = &dnsengine_default;
  39         else {
  40                 iolog_trigger(IOLOG_FATAL, "found no useable IO DNS engine");
  41                 return;
  42         }
  43         iolog_trigger(IOLOG_DEBUG, "using %s IODNS engine", dnsengine->name);
  44 }
  45
  46 void _init_iodns() {
  47         iodns_init_engine();
  48 }
  49
  50 struct _IODNSQuery *_create_dnsquery() {
  51         struct _IODNSQuery *query = calloc(1, sizeof(*query));
  52         if(!query) {
  53                 iolog_trigger(IOLOG_ERROR, "could not allocate memory for _IODNSQuery in %s:%d", __FILE__, __LINE__);
  54                 return NULL;
  55         }
  56         if(iodnsquery_last)
  57                 iodnsquery_last->next = query;
  58         else
  59                 iodnsquery_first = query;
  60         query->prev = iodnsquery_last;
  61         iodnsquery_last = query;
  62         return query;
  63 }
  64
  65 void _start_dnsquery(struct _IODNSQuery *query) {
  66         query->flags |= IODNSFLAG_RUNNING;
  67         dnsengine->add(query);
  68 }
  69
  70 void _free_dnsquery(struct _IODNSQuery *query) {
  71         if(query->prev)
  72                 query->prev->next = query->next;
  73         else
  74                 iodnsquery_first = query->next;
  75         if(query->next)
  76                 query->next->prev = query->prev;
  77         else
  78                 iodnsquery_last = query->prev;
  79         if((query->type & IODNS_REVERSE) && query->request.addr.address)
  80                 free(query->request.addr.address);
  81         free(query);
  82 }
  83
  84 void _stop_dnsquery(struct _IODNSQuery *query) {
  85         if((query->flags & IODNSFLAG_RUNNING)) {
  86                 query->flags &= ~IODNSFLAG_RUNNING;
  87                 dnsengine->remove(query);
  88         }
  89         if(!(query->flags & IODNSFLAG_PROCESSING))
  90                 _free_dnsquery(query);
  91 }
  92
  93 void iodns_event_callback(struct _IODNSQuery *query, enum IODNSEventType state) {
  94         if((query->flags & IODNSFLAG_PARENT_PUBLIC)) {
  95                 struct IODNSQuery *descriptor = query->parent;
  96                 struct IODNSEvent event;
  97                 event.type = state;
  98                 event.query = descriptor;
  99                 event.result = query->result;
 100
 101                 descriptor->query = NULL;
 102                 _stop_dnsquery(query);
 103
 104                 if(descriptor->callback)
 105                         descriptor->callback(&event);
 106
 107                 iogc_add(descriptor);
 108         } else if((query->flags & IODNSFLAG_PARENT_SOCKET)) {
 109                 struct IODNSEvent event;
 110                 event.type = state;
 111                 event.query = NULL;
 112                 event.result = query->result;
 113                 void *parent = query->parent;
 114
 115                 _stop_dnsquery(query);
 116                 iosocket_lookup_callback(parent, &event);
 117
 118         }
 119 }
 120
 121 void iodns_poll() {
 122         if(dnsengine)
 123                 dnsengine->loop();
 124 }
 125
 126 /* public functions */
 127
 128 struct IODNSQuery *iodns_getaddrinfo(char *hostname, int records, iodns_callback *callback) {
 129         if(!(records & IODNS_FORWARD) || !hostname || !callback)
 130                 return NULL;
 131
 132         struct IODNSQuery *descriptor = calloc(1, sizeof(*descriptor));
 133         if(!descriptor) {
 134                 iolog_trigger(IOLOG_ERROR, "could not allocate memory for IODNSQuery in %s:%d", __FILE__, __LINE__);
 135                 return NULL;
 136         }
 137
 138         struct _IODNSQuery *query = _create_dnsquery();
 139         if(!query) {
 140                 free(descriptor);
 141                 return NULL;
 142         }
 143
 144         query->parent = descriptor;
 145         query->flags |= IODNSFLAG_PARENT_PUBLIC;
 146         descriptor->query = query;
 147
 148         query->request.host = strdup(hostname);
 149         query->type = (records & IODNS_FORWARD);
 150
 151         descriptor->callback = callback;
 152
 153         _start_dnsquery(query);
 154         return descriptor;
 155 }
 156
 157 struct IODNSQuery *iodns_getnameinfo(const struct sockaddr *addr, size_t addrlen, iodns_callback *callback) {
 158         if(!addr || !callback)
 159                 return NULL;
 160
 161         struct IODNSQuery *descriptor = calloc(1, sizeof(*descriptor));
 162         if(!descriptor) {
 163                 iolog_trigger(IOLOG_ERROR, "could not allocate memory for IODNSQuery in %s:%d", __FILE__, __LINE__);
 164                 return NULL;
 165         }
 166
 167         struct _IODNSQuery *query = _create_dnsquery();
 168         if(!query) {
 169                 free(descriptor);
 170                 return NULL;
 171         }
 172
 173         query->parent = descriptor;
 174         query->flags |= IODNSFLAG_PARENT_PUBLIC;
 175         descriptor->query = query;
 176
 177         query->type = IODNS_RECORD_PTR;
 178         query->request.addr.addresslen = addrlen;
 179         query->request.addr.address = malloc(addrlen);
 180         if(!query->request.addr.address) {
 181                 iolog_trigger(IOLOG_ERROR, "could not allocate memory for sockaddr in %s:%d", __FILE__, __LINE__);
 182                 _free_dnsquery(query);
 183                 free(descriptor);
 184                 return NULL;
 185         }
 186         memcpy(query->request.addr.address, addr, addrlen);
 187
 188         descriptor->callback = callback;
 189
 190         _start_dnsquery(query);
 191         return descriptor;
 192 }
 193
 194 void iodns_abort(struct IODNSQuery *descriptor) {
 195         if(!descriptor)
 196                 return;
 197
 198         struct _IODNSQuery *query = descriptor->query;
 199         if(!query) {
 200                 iolog_trigger(IOLOG_WARNING, "called iodns_abort for destroyed IODNSQuery in %s:%d", __FILE__, __LINE__);
 201                 return;
 202         }
 203
 204         _stop_dnsquery(query);
 205 }
 206
 207 void iodns_free_result(struct IODNSResult *result) {
 208         struct IODNSResult *next;
 209         for(;result;result = next) {
 210                 next = result->next;
 211
 212                 if((result->type & IODNS_FORWARD)) {
 213                         if(result->result.addr.address)
 214                                 free(result->result.addr.address);
 215                 }
 216                 if((result->type & IODNS_REVERSE)) {
 217                         if(result->result.host)
 218                                 free(result->result.host);
 219                 }
 220                 free(result);
 221         }
 222 }
 223