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00026 #include "asterisk.h"
00027
00028 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 271123 $")
00029
00030 #include <sys/types.h>
00031 #include <netinet/in.h>
00032 #include <sys/socket.h>
00033 #include <arpa/inet.h>
00034 #include <resolv.h>
00035 #include <stdio.h>
00036 #include <string.h>
00037 #include <unistd.h>
00038 #include <stdlib.h>
00039 #include <regex.h>
00040 #include <signal.h>
00041
00042 #include "asterisk/dnsmgr.h"
00043 #include "asterisk/linkedlists.h"
00044 #include "asterisk/utils.h"
00045 #include "asterisk/config.h"
00046 #include "asterisk/logger.h"
00047 #include "asterisk/sched.h"
00048 #include "asterisk/options.h"
00049 #include "asterisk/cli.h"
00050
00051 static struct sched_context *sched;
00052 static int refresh_sched = -1;
00053 static pthread_t refresh_thread = AST_PTHREADT_NULL;
00054
00055 struct ast_dnsmgr_entry {
00056
00057 struct in_addr *result;
00058
00059 int changed:1;
00060 ast_mutex_t lock;
00061 AST_LIST_ENTRY(ast_dnsmgr_entry) list;
00062
00063 char name[1];
00064 };
00065
00066 static AST_LIST_HEAD_STATIC(entry_list, ast_dnsmgr_entry);
00067
00068 AST_MUTEX_DEFINE_STATIC(refresh_lock);
00069
00070 #define REFRESH_DEFAULT 300
00071
00072 static int enabled;
00073 static int refresh_interval;
00074
00075 struct refresh_info {
00076 struct entry_list *entries;
00077 int verbose;
00078 unsigned int regex_present:1;
00079 regex_t filter;
00080 };
00081
00082 static struct refresh_info master_refresh_info = {
00083 .entries = &entry_list,
00084 .verbose = 0,
00085 };
00086
00087 struct ast_dnsmgr_entry *ast_dnsmgr_get(const char *name, struct in_addr *result)
00088 {
00089 struct ast_dnsmgr_entry *entry;
00090
00091 if (!result || ast_strlen_zero(name) || !(entry = ast_calloc(1, sizeof(*entry) + strlen(name))))
00092 return NULL;
00093
00094 entry->result = result;
00095 ast_mutex_init(&entry->lock);
00096 strcpy(entry->name, name);
00097
00098 AST_LIST_LOCK(&entry_list);
00099 AST_LIST_INSERT_HEAD(&entry_list, entry, list);
00100 AST_LIST_UNLOCK(&entry_list);
00101
00102 return entry;
00103 }
00104
00105 void ast_dnsmgr_release(struct ast_dnsmgr_entry *entry)
00106 {
00107 if (!entry)
00108 return;
00109
00110 AST_LIST_LOCK(&entry_list);
00111 AST_LIST_REMOVE(&entry_list, entry, list);
00112 AST_LIST_UNLOCK(&entry_list);
00113 if (option_verbose > 3)
00114 ast_verbose(VERBOSE_PREFIX_4 "removing dns manager for '%s'\n", entry->name);
00115
00116 ast_mutex_destroy(&entry->lock);
00117 free(entry);
00118 }
00119
00120 int ast_dnsmgr_lookup(const char *name, struct in_addr *result, struct ast_dnsmgr_entry **dnsmgr)
00121 {
00122 struct ast_hostent ahp;
00123 struct hostent *hp;
00124
00125 if (ast_strlen_zero(name) || !result || !dnsmgr)
00126 return -1;
00127
00128 if (*dnsmgr && !strcasecmp((*dnsmgr)->name, name))
00129 return 0;
00130
00131 if (option_verbose > 3)
00132 ast_verbose(VERBOSE_PREFIX_4 "doing dnsmgr_lookup for '%s'\n", name);
00133
00134
00135
00136 if (inet_aton(name, result))
00137 return 0;
00138
00139
00140 if ((hp = ast_gethostbyname(name, &ahp)))
00141 memcpy(result, hp->h_addr, sizeof(result));
00142
00143
00144 if (!enabled)
00145 return 0;
00146
00147 if (option_verbose > 2)
00148 ast_verbose(VERBOSE_PREFIX_2 "adding dns manager for '%s'\n", name);
00149 *dnsmgr = ast_dnsmgr_get(name, result);
00150 return !*dnsmgr;
00151 }
00152
00153
00154
00155
00156 static int dnsmgr_refresh(struct ast_dnsmgr_entry *entry, int verbose)
00157 {
00158 struct ast_hostent ahp;
00159 struct hostent *hp;
00160 char iabuf[INET_ADDRSTRLEN];
00161 char iabuf2[INET_ADDRSTRLEN];
00162 struct in_addr tmp;
00163 int changed = 0;
00164
00165 ast_mutex_lock(&entry->lock);
00166 if (verbose && (option_verbose > 2))
00167 ast_verbose(VERBOSE_PREFIX_2 "refreshing '%s'\n", entry->name);
00168
00169 if ((hp = ast_gethostbyname(entry->name, &ahp))) {
00170
00171 memcpy(&tmp, hp->h_addr, sizeof(tmp));
00172 if (tmp.s_addr != entry->result->s_addr) {
00173 ast_copy_string(iabuf, ast_inet_ntoa(*entry->result), sizeof(iabuf));
00174 ast_copy_string(iabuf2, ast_inet_ntoa(tmp), sizeof(iabuf2));
00175 ast_log(LOG_NOTICE, "host '%s' changed from %s to %s\n",
00176 entry->name, iabuf, iabuf2);
00177 memcpy(entry->result, hp->h_addr, sizeof(entry->result));
00178 changed = entry->changed = 1;
00179 }
00180
00181 }
00182 ast_mutex_unlock(&entry->lock);
00183 return changed;
00184 }
00185
00186 int ast_dnsmgr_refresh(struct ast_dnsmgr_entry *entry)
00187 {
00188 return dnsmgr_refresh(entry, 0);
00189 }
00190
00191
00192
00193
00194 int ast_dnsmgr_changed(struct ast_dnsmgr_entry *entry)
00195 {
00196 int changed;
00197
00198 ast_mutex_lock(&entry->lock);
00199
00200 changed = entry->changed;
00201 entry->changed = 0;
00202
00203 ast_mutex_unlock(&entry->lock);
00204
00205 return changed;
00206 }
00207
00208 static void *do_refresh(void *data)
00209 {
00210 for (;;) {
00211 pthread_testcancel();
00212 usleep((ast_sched_wait(sched)*1000));
00213 pthread_testcancel();
00214 ast_sched_runq(sched);
00215 }
00216 return NULL;
00217 }
00218
00219 static int refresh_list(const void *data)
00220 {
00221 struct refresh_info *info = (struct refresh_info *)data;
00222 struct ast_dnsmgr_entry *entry;
00223
00224
00225 if (ast_mutex_trylock(&refresh_lock)) {
00226 if (info->verbose)
00227 ast_log(LOG_WARNING, "DNS Manager refresh already in progress.\n");
00228 return -1;
00229 }
00230
00231 if (option_verbose > 2)
00232 ast_verbose(VERBOSE_PREFIX_2 "Refreshing DNS lookups.\n");
00233 AST_LIST_LOCK(info->entries);
00234 AST_LIST_TRAVERSE(info->entries, entry, list) {
00235 if (info->regex_present && regexec(&info->filter, entry->name, 0, NULL, 0))
00236 continue;
00237
00238 dnsmgr_refresh(entry, info->verbose);
00239 }
00240 AST_LIST_UNLOCK(info->entries);
00241
00242 ast_mutex_unlock(&refresh_lock);
00243
00244
00245 return refresh_interval * 1000;
00246 }
00247
00248 void dnsmgr_start_refresh(void)
00249 {
00250 if (refresh_sched > -1) {
00251 AST_SCHED_DEL(sched, refresh_sched);
00252 refresh_sched = ast_sched_add_variable(sched, 100, refresh_list, &master_refresh_info, 1);
00253 }
00254 }
00255
00256 static int do_reload(int loading);
00257
00258 static int handle_cli_reload(int fd, int argc, char *argv[])
00259 {
00260 if (argc > 2)
00261 return RESULT_SHOWUSAGE;
00262
00263 do_reload(0);
00264 return 0;
00265 }
00266
00267 static int handle_cli_refresh(int fd, int argc, char *argv[])
00268 {
00269 struct refresh_info info = {
00270 .entries = &entry_list,
00271 .verbose = 1,
00272 };
00273
00274 if(!enabled) {
00275 ast_cli(fd, "DNS Manager is disabled.\n");
00276 return 0;
00277 }
00278
00279 if (argc > 3)
00280 return RESULT_SHOWUSAGE;
00281
00282 if (argc == 3) {
00283 if (regcomp(&info.filter, argv[2], REG_EXTENDED | REG_NOSUB))
00284 return RESULT_SHOWUSAGE;
00285 else
00286 info.regex_present = 1;
00287 }
00288
00289 refresh_list(&info);
00290
00291 if (info.regex_present)
00292 regfree(&info.filter);
00293
00294 return 0;
00295 }
00296
00297 static int handle_cli_status(int fd, int argc, char *argv[])
00298 {
00299 int count = 0;
00300 struct ast_dnsmgr_entry *entry;
00301
00302 if (argc > 2)
00303 return RESULT_SHOWUSAGE;
00304
00305 ast_cli(fd, "DNS Manager: %s\n", enabled ? "enabled" : "disabled");
00306 ast_cli(fd, "Refresh Interval: %d seconds\n", refresh_interval);
00307 AST_LIST_LOCK(&entry_list);
00308 AST_LIST_TRAVERSE(&entry_list, entry, list)
00309 count++;
00310 AST_LIST_UNLOCK(&entry_list);
00311 ast_cli(fd, "Number of entries: %d\n", count);
00312
00313 return 0;
00314 }
00315
00316 static struct ast_cli_entry cli_reload = {
00317 { "dnsmgr", "reload", NULL },
00318 handle_cli_reload, "Reloads the DNS manager configuration",
00319 "Usage: dnsmgr reload\n"
00320 " Reloads the DNS manager configuration.\n"
00321 };
00322
00323 static struct ast_cli_entry cli_refresh = {
00324 { "dnsmgr", "refresh", NULL },
00325 handle_cli_refresh, "Performs an immediate refresh",
00326 "Usage: dnsmgr refresh [pattern]\n"
00327 " Peforms an immediate refresh of the managed DNS entries.\n"
00328 " Optional regular expression pattern is used to filter the entries to refresh.\n",
00329 };
00330
00331 static struct ast_cli_entry cli_status = {
00332 { "dnsmgr", "status", NULL },
00333 handle_cli_status, "Display the DNS manager status",
00334 "Usage: dnsmgr status\n"
00335 " Displays the DNS manager status.\n"
00336 };
00337
00338 int dnsmgr_init(void)
00339 {
00340 if (!(sched = sched_context_create())) {
00341 ast_log(LOG_ERROR, "Unable to create schedule context.\n");
00342 return -1;
00343 }
00344 ast_cli_register(&cli_reload);
00345 ast_cli_register(&cli_status);
00346 ast_cli_register(&cli_refresh);
00347 return do_reload(1);
00348 }
00349
00350 int dnsmgr_reload(void)
00351 {
00352 return do_reload(0);
00353 }
00354
00355 static int do_reload(int loading)
00356 {
00357 struct ast_config *config;
00358 const char *interval_value;
00359 const char *enabled_value;
00360 int interval;
00361 int was_enabled;
00362 int res = -1;
00363
00364
00365 ast_mutex_lock(&refresh_lock);
00366
00367
00368 refresh_interval = REFRESH_DEFAULT;
00369 was_enabled = enabled;
00370 enabled = 0;
00371
00372 AST_SCHED_DEL(sched, refresh_sched);
00373
00374 if ((config = ast_config_load("dnsmgr.conf"))) {
00375 if ((enabled_value = ast_variable_retrieve(config, "general", "enable"))) {
00376 enabled = ast_true(enabled_value);
00377 }
00378 if ((interval_value = ast_variable_retrieve(config, "general", "refreshinterval"))) {
00379 if (sscanf(interval_value, "%30d", &interval) < 1)
00380 ast_log(LOG_WARNING, "Unable to convert '%s' to a numeric value.\n", interval_value);
00381 else if (interval < 0)
00382 ast_log(LOG_WARNING, "Invalid refresh interval '%d' specified, using default\n", interval);
00383 else
00384 refresh_interval = interval;
00385 }
00386 ast_config_destroy(config);
00387 }
00388
00389 if (enabled && refresh_interval)
00390 ast_log(LOG_NOTICE, "Managed DNS entries will be refreshed every %d seconds.\n", refresh_interval);
00391
00392
00393
00394 if (enabled) {
00395 if (!was_enabled && (refresh_thread == AST_PTHREADT_NULL)) {
00396 if (ast_pthread_create_background(&refresh_thread, NULL, do_refresh, NULL) < 0) {
00397 ast_log(LOG_ERROR, "Unable to start refresh thread.\n");
00398 }
00399 }
00400
00401 refresh_sched = ast_sched_add_variable(sched, 100, refresh_list, &master_refresh_info, 1);
00402 res = 0;
00403 }
00404
00405
00406 else if (!enabled && was_enabled && (refresh_thread != AST_PTHREADT_NULL)) {
00407
00408 pthread_cancel(refresh_thread);
00409 pthread_kill(refresh_thread, SIGURG);
00410 pthread_join(refresh_thread, NULL);
00411 refresh_thread = AST_PTHREADT_NULL;
00412 res = 0;
00413 }
00414 else
00415 res = 0;
00416
00417 ast_mutex_unlock(&refresh_lock);
00418
00419 return res;
00420 }