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_socket_callback(struct _IOSocket *iosock, int wantread, int wantwrite) {
  94         if(dnsengine && dnsengine->socket_callback)
  95                 dnsengine->socket_callback(iosock, wantread, wantwrite);
  96 }
  97
  98 void iodns_event_callback(struct _IODNSQuery *query, enum IODNSEventType state) {
  99         if((query->flags & IODNSFLAG_PARENT_PUBLIC)) {
 100                 struct IODNSQuery *descriptor = query->parent;
 101                 struct IODNSEvent event;
 102                 event.type = state;
 103                 event.query = descriptor;
 104                 event.result = query->result;
 105
 106                 descriptor->query = NULL;
 107                 _stop_dnsquery(query);
 108
 109                 if(descriptor->callback)
 110                         descriptor->callback(&event);
 111
 112                 iogc_add(descriptor);
 113         } else if((query->flags & IODNSFLAG_PARENT_SOCKET)) {
 114                 struct IODNSEvent event;
 115                 event.type = state;
 116                 event.query = NULL;
 117                 event.result = query->result;
 118                 void *parent = query->parent;
 119
 120                 _stop_dnsquery(query);
 121                 iosocket_lookup_callback(parent, &event);
 122
 123         }
 124 }
 125
 126 void iodns_poll() {
 127         if(dnsengine)
 128                 dnsengine->loop();
 129 }
 130
 131 /* public functions */
 132
 133 struct IODNSQuery *iodns_getaddrinfo(char *hostname, int records, iodns_callback *callback) {
 134         if(!(records & IODNS_FORWARD) || !hostname || !callback)
 135                 return NULL;
 136
 137         struct IODNSQuery *descriptor = calloc(1, sizeof(*descriptor));
 138         if(!descriptor) {
 139                 iolog_trigger(IOLOG_ERROR, "could not allocate memory for IODNSQuery in %s:%d", __FILE__, __LINE__);
 140                 return NULL;
 141         }
 142
 143         struct _IODNSQuery *query = _create_dnsquery();
 144         if(!query) {
 145                 free(descriptor);
 146                 return NULL;
 147         }
 148
 149         query->parent = descriptor;
 150         query->flags |= IODNSFLAG_PARENT_PUBLIC;
 151         descriptor->query = query;
 152
 153         query->request.host = strdup(hostname);
 154         query->type = (records & IODNS_FORWARD);
 155
 156         descriptor->callback = callback;
 157
 158         _start_dnsquery(query);
 159         return descriptor;
 160 }
 161
 162 struct IODNSQuery *iodns_getnameinfo(const struct sockaddr *addr, size_t addrlen, iodns_callback *callback) {
 163         if(!addr || !callback)
 164                 return NULL;
 165
 166         struct IODNSQuery *descriptor = calloc(1, sizeof(*descriptor));
 167         if(!descriptor) {
 168                 iolog_trigger(IOLOG_ERROR, "could not allocate memory for IODNSQuery in %s:%d", __FILE__, __LINE__);
 169                 return NULL;
 170         }
 171
 172         struct _IODNSQuery *query = _create_dnsquery();
 173         if(!query) {
 174                 free(descriptor);
 175                 return NULL;
 176         }
 177
 178         query->parent = descriptor;
 179         query->flags |= IODNSFLAG_PARENT_PUBLIC;
 180         descriptor->query = query;
 181
 182         query->type = IODNS_RECORD_PTR;
 183         query->request.addr.addresslen = addrlen;
 184         query->request.addr.address = malloc(addrlen);
 185         if(!query->request.addr.address) {
 186                 iolog_trigger(IOLOG_ERROR, "could not allocate memory for sockaddr in %s:%d", __FILE__, __LINE__);
 187                 _free_dnsquery(query);
 188                 free(descriptor);
 189                 return NULL;
 190         }
 191         memcpy(query->request.addr.address, addr, addrlen);
 192
 193         descriptor->callback = callback;
 194
 195         _start_dnsquery(query);
 196         return descriptor;
 197 }
 198
 199 void iodns_abort(struct IODNSQuery *descriptor) {
 200         if(!descriptor)
 201                 return;
 202
 203         struct _IODNSQuery *query = descriptor->query;
 204         if(!query) {
 205                 iolog_trigger(IOLOG_WARNING, "called iodns_abort for destroyed IODNSQuery in %s:%d", __FILE__, __LINE__);
 206                 return;
 207         }
 208
 209         _stop_dnsquery(query);
 210 }
 211
 212 void iodns_free_result(struct IODNSResult *result) {
 213         struct IODNSResult *next;
 214         for(;result;result = next) {
 215                 next = result->next;
 216
 217                 if((result->type & IODNS_FORWARD)) {
 218                         if(result->result.addr.address)
 219                                 free(result->result.addr.address);
 220                 }
 221                 if((result->type & IODNS_REVERSE)) {
 222                         if(result->result.host)
 223                                 free(result->result.host);
 224                 }
 225                 free(result);
 226         }
 227 }
 228