/asterisk-1.4/main/dnsmgr.c
C | 420 lines | 298 code | 75 blank | 47 comment | 54 complexity | 1b335afc1f205645ae863eb07b9db424 MD5 | raw file
- /*
- * Asterisk -- An open source telephony toolkit.
- *
- * Copyright (C) 2005-2006, Kevin P. Fleming
- *
- * Kevin P. Fleming <kpfleming@digium.com>
- *
- * See http://www.asterisk.org for more information about
- * the Asterisk project. Please do not directly contact
- * any of the maintainers of this project for assistance;
- * the project provides a web site, mailing lists and IRC
- * channels for your use.
- *
- * This program is free software, distributed under the terms of
- * the GNU General Public License Version 2. See the LICENSE file
- * at the top of the source tree.
- */
- /*! \file
- *
- * \brief Background DNS update manager
- *
- * \author Kevin P. Fleming <kpfleming@digium.com>
- */
- #include "asterisk.h"
- ASTERISK_FILE_VERSION(__FILE__, "$Revision: 271123 $")
- #include <sys/types.h>
- #include <netinet/in.h>
- #include <sys/socket.h>
- #include <arpa/inet.h>
- #include <resolv.h>
- #include <stdio.h>
- #include <string.h>
- #include <unistd.h>
- #include <stdlib.h>
- #include <regex.h>
- #include <signal.h>
- #include "asterisk/dnsmgr.h"
- #include "asterisk/linkedlists.h"
- #include "asterisk/utils.h"
- #include "asterisk/config.h"
- #include "asterisk/logger.h"
- #include "asterisk/sched.h"
- #include "asterisk/options.h"
- #include "asterisk/cli.h"
- static struct sched_context *sched;
- static int refresh_sched = -1;
- static pthread_t refresh_thread = AST_PTHREADT_NULL;
- struct ast_dnsmgr_entry {
- /*! where we will store the resulting address */
- struct in_addr *result;
- /*! Set to 1 if the entry changes */
- int changed:1;
- ast_mutex_t lock;
- AST_LIST_ENTRY(ast_dnsmgr_entry) list;
- /*! just 1 here, but we use calloc to allocate the correct size */
- char name[1];
- };
- static AST_LIST_HEAD_STATIC(entry_list, ast_dnsmgr_entry);
- AST_MUTEX_DEFINE_STATIC(refresh_lock);
- #define REFRESH_DEFAULT 300
- static int enabled;
- static int refresh_interval;
- struct refresh_info {
- struct entry_list *entries;
- int verbose;
- unsigned int regex_present:1;
- regex_t filter;
- };
- static struct refresh_info master_refresh_info = {
- .entries = &entry_list,
- .verbose = 0,
- };
- struct ast_dnsmgr_entry *ast_dnsmgr_get(const char *name, struct in_addr *result)
- {
- struct ast_dnsmgr_entry *entry;
- if (!result || ast_strlen_zero(name) || !(entry = ast_calloc(1, sizeof(*entry) + strlen(name))))
- return NULL;
- entry->result = result;
- ast_mutex_init(&entry->lock);
- strcpy(entry->name, name);
- AST_LIST_LOCK(&entry_list);
- AST_LIST_INSERT_HEAD(&entry_list, entry, list);
- AST_LIST_UNLOCK(&entry_list);
- return entry;
- }
- void ast_dnsmgr_release(struct ast_dnsmgr_entry *entry)
- {
- if (!entry)
- return;
- AST_LIST_LOCK(&entry_list);
- AST_LIST_REMOVE(&entry_list, entry, list);
- AST_LIST_UNLOCK(&entry_list);
- if (option_verbose > 3)
- ast_verbose(VERBOSE_PREFIX_4 "removing dns manager for '%s'\n", entry->name);
- ast_mutex_destroy(&entry->lock);
- free(entry);
- }
- int ast_dnsmgr_lookup(const char *name, struct in_addr *result, struct ast_dnsmgr_entry **dnsmgr)
- {
- struct ast_hostent ahp;
- struct hostent *hp;
- if (ast_strlen_zero(name) || !result || !dnsmgr)
- return -1;
- if (*dnsmgr && !strcasecmp((*dnsmgr)->name, name))
- return 0;
- if (option_verbose > 3)
- ast_verbose(VERBOSE_PREFIX_4 "doing dnsmgr_lookup for '%s'\n", name);
- /* if it's actually an IP address and not a name,
- there's no need for a managed lookup */
- if (inet_aton(name, result))
- return 0;
- /* do a lookup now but add a manager so it will automagically get updated in the background */
- if ((hp = ast_gethostbyname(name, &ahp)))
- memcpy(result, hp->h_addr, sizeof(result));
-
- /* if dnsmgr is not enable don't bother adding an entry */
- if (!enabled)
- return 0;
-
- if (option_verbose > 2)
- ast_verbose(VERBOSE_PREFIX_2 "adding dns manager for '%s'\n", name);
- *dnsmgr = ast_dnsmgr_get(name, result);
- return !*dnsmgr;
- }
- /*
- * Refresh a dnsmgr entry
- */
- static int dnsmgr_refresh(struct ast_dnsmgr_entry *entry, int verbose)
- {
- struct ast_hostent ahp;
- struct hostent *hp;
- char iabuf[INET_ADDRSTRLEN];
- char iabuf2[INET_ADDRSTRLEN];
- struct in_addr tmp;
- int changed = 0;
-
- ast_mutex_lock(&entry->lock);
- if (verbose && (option_verbose > 2))
- ast_verbose(VERBOSE_PREFIX_2 "refreshing '%s'\n", entry->name);
- if ((hp = ast_gethostbyname(entry->name, &ahp))) {
- /* check to see if it has changed, do callback if requested (where de callback is defined ????) */
- memcpy(&tmp, hp->h_addr, sizeof(tmp));
- if (tmp.s_addr != entry->result->s_addr) {
- ast_copy_string(iabuf, ast_inet_ntoa(*entry->result), sizeof(iabuf));
- ast_copy_string(iabuf2, ast_inet_ntoa(tmp), sizeof(iabuf2));
- ast_log(LOG_NOTICE, "host '%s' changed from %s to %s\n",
- entry->name, iabuf, iabuf2);
- memcpy(entry->result, hp->h_addr, sizeof(entry->result));
- changed = entry->changed = 1;
- }
-
- }
- ast_mutex_unlock(&entry->lock);
- return changed;
- }
- int ast_dnsmgr_refresh(struct ast_dnsmgr_entry *entry)
- {
- return dnsmgr_refresh(entry, 0);
- }
- /*
- * Check if dnsmgr entry has changed from since last call to this function
- */
- int ast_dnsmgr_changed(struct ast_dnsmgr_entry *entry)
- {
- int changed;
- ast_mutex_lock(&entry->lock);
- changed = entry->changed;
- entry->changed = 0;
- ast_mutex_unlock(&entry->lock);
-
- return changed;
- }
- static void *do_refresh(void *data)
- {
- for (;;) {
- pthread_testcancel();
- usleep((ast_sched_wait(sched)*1000));
- pthread_testcancel();
- ast_sched_runq(sched);
- }
- return NULL;
- }
- static int refresh_list(const void *data)
- {
- struct refresh_info *info = (struct refresh_info *)data;
- struct ast_dnsmgr_entry *entry;
- /* if a refresh or reload is already in progress, exit now */
- if (ast_mutex_trylock(&refresh_lock)) {
- if (info->verbose)
- ast_log(LOG_WARNING, "DNS Manager refresh already in progress.\n");
- return -1;
- }
- if (option_verbose > 2)
- ast_verbose(VERBOSE_PREFIX_2 "Refreshing DNS lookups.\n");
- AST_LIST_LOCK(info->entries);
- AST_LIST_TRAVERSE(info->entries, entry, list) {
- if (info->regex_present && regexec(&info->filter, entry->name, 0, NULL, 0))
- continue;
- dnsmgr_refresh(entry, info->verbose);
- }
- AST_LIST_UNLOCK(info->entries);
- ast_mutex_unlock(&refresh_lock);
- /* automatically reschedule based on the interval */
- return refresh_interval * 1000;
- }
- void dnsmgr_start_refresh(void)
- {
- if (refresh_sched > -1) {
- AST_SCHED_DEL(sched, refresh_sched);
- refresh_sched = ast_sched_add_variable(sched, 100, refresh_list, &master_refresh_info, 1);
- }
- }
- static int do_reload(int loading);
- static int handle_cli_reload(int fd, int argc, char *argv[])
- {
- if (argc > 2)
- return RESULT_SHOWUSAGE;
- do_reload(0);
- return 0;
- }
- static int handle_cli_refresh(int fd, int argc, char *argv[])
- {
- struct refresh_info info = {
- .entries = &entry_list,
- .verbose = 1,
- };
- if(!enabled) {
- ast_cli(fd, "DNS Manager is disabled.\n");
- return 0;
- }
- if (argc > 3)
- return RESULT_SHOWUSAGE;
- if (argc == 3) {
- if (regcomp(&info.filter, argv[2], REG_EXTENDED | REG_NOSUB))
- return RESULT_SHOWUSAGE;
- else
- info.regex_present = 1;
- }
- refresh_list(&info);
- if (info.regex_present)
- regfree(&info.filter);
- return 0;
- }
- static int handle_cli_status(int fd, int argc, char *argv[])
- {
- int count = 0;
- struct ast_dnsmgr_entry *entry;
- if (argc > 2)
- return RESULT_SHOWUSAGE;
- ast_cli(fd, "DNS Manager: %s\n", enabled ? "enabled" : "disabled");
- ast_cli(fd, "Refresh Interval: %d seconds\n", refresh_interval);
- AST_LIST_LOCK(&entry_list);
- AST_LIST_TRAVERSE(&entry_list, entry, list)
- count++;
- AST_LIST_UNLOCK(&entry_list);
- ast_cli(fd, "Number of entries: %d\n", count);
- return 0;
- }
- static struct ast_cli_entry cli_reload = {
- { "dnsmgr", "reload", NULL },
- handle_cli_reload, "Reloads the DNS manager configuration",
- "Usage: dnsmgr reload\n"
- " Reloads the DNS manager configuration.\n"
- };
- static struct ast_cli_entry cli_refresh = {
- { "dnsmgr", "refresh", NULL },
- handle_cli_refresh, "Performs an immediate refresh",
- "Usage: dnsmgr refresh [pattern]\n"
- " Peforms an immediate refresh of the managed DNS entries.\n"
- " Optional regular expression pattern is used to filter the entries to refresh.\n",
- };
- static struct ast_cli_entry cli_status = {
- { "dnsmgr", "status", NULL },
- handle_cli_status, "Display the DNS manager status",
- "Usage: dnsmgr status\n"
- " Displays the DNS manager status.\n"
- };
- int dnsmgr_init(void)
- {
- if (!(sched = sched_context_create())) {
- ast_log(LOG_ERROR, "Unable to create schedule context.\n");
- return -1;
- }
- ast_cli_register(&cli_reload);
- ast_cli_register(&cli_status);
- ast_cli_register(&cli_refresh);
- return do_reload(1);
- }
- int dnsmgr_reload(void)
- {
- return do_reload(0);
- }
- static int do_reload(int loading)
- {
- struct ast_config *config;
- const char *interval_value;
- const char *enabled_value;
- int interval;
- int was_enabled;
- int res = -1;
- /* ensure that no refresh cycles run while the reload is in progress */
- ast_mutex_lock(&refresh_lock);
- /* reset defaults in preparation for reading config file */
- refresh_interval = REFRESH_DEFAULT;
- was_enabled = enabled;
- enabled = 0;
- AST_SCHED_DEL(sched, refresh_sched);
- if ((config = ast_config_load("dnsmgr.conf"))) {
- if ((enabled_value = ast_variable_retrieve(config, "general", "enable"))) {
- enabled = ast_true(enabled_value);
- }
- if ((interval_value = ast_variable_retrieve(config, "general", "refreshinterval"))) {
- if (sscanf(interval_value, "%30d", &interval) < 1)
- ast_log(LOG_WARNING, "Unable to convert '%s' to a numeric value.\n", interval_value);
- else if (interval < 0)
- ast_log(LOG_WARNING, "Invalid refresh interval '%d' specified, using default\n", interval);
- else
- refresh_interval = interval;
- }
- ast_config_destroy(config);
- }
- if (enabled && refresh_interval)
- ast_log(LOG_NOTICE, "Managed DNS entries will be refreshed every %d seconds.\n", refresh_interval);
- /* if this reload enabled the manager, create the background thread
- if it does not exist */
- if (enabled) {
- if (!was_enabled && (refresh_thread == AST_PTHREADT_NULL)) {
- if (ast_pthread_create_background(&refresh_thread, NULL, do_refresh, NULL) < 0) {
- ast_log(LOG_ERROR, "Unable to start refresh thread.\n");
- }
- }
- /* make a background refresh happen right away */
- refresh_sched = ast_sched_add_variable(sched, 100, refresh_list, &master_refresh_info, 1);
- res = 0;
- }
- /* if this reload disabled the manager and there is a background thread,
- kill it */
- else if (!enabled && was_enabled && (refresh_thread != AST_PTHREADT_NULL)) {
- /* wake up the thread so it will exit */
- pthread_cancel(refresh_thread);
- pthread_kill(refresh_thread, SIGURG);
- pthread_join(refresh_thread, NULL);
- refresh_thread = AST_PTHREADT_NULL;
- res = 0;
- }
- else
- res = 0;
- ast_mutex_unlock(&refresh_lock);
- return res;
- }