git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@5490 65c4cc65-6c06-0410-ace0-fbb531ad65f3
354 lines
8.6 KiB
C
Executable file
354 lines
8.6 KiB
C
Executable file
/*
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* Asterisk -- A telephony toolkit for Linux.
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*
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* Background DNS update manager
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*
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* Copyright (C) 2005, Kevin P. Fleming
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*
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* Kevin P. Fleming <kpfleming@digium.com>
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License
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*/
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#include <sys/types.h>
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#include <netinet/in.h>
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#include <sys/socket.h>
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#include <arpa/inet.h>
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#include <resolv.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <regex.h>
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#include <signal.h>
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#include "asterisk/dnsmgr.h"
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#include "asterisk/linkedlists.h"
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#include "asterisk/utils.h"
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#include "asterisk/config.h"
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#include "asterisk/logger.h"
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#include "asterisk/sched.h"
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#include "asterisk/options.h"
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#include "asterisk/cli.h"
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#include "asterisk.h"
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static struct sched_context *sched;
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static int refresh_sched = -1;
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static pthread_t refresh_thread = AST_PTHREADT_NULL;
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struct ast_dnsmgr_entry {
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struct in_addr *result;
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AST_LIST_ENTRY(ast_dnsmgr_entry) list;
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char name[1];
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};
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static AST_LIST_HEAD(entry_list, ast_dnsmgr_entry) entry_list;
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AST_MUTEX_DEFINE_STATIC(refresh_lock);
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#define REFRESH_DEFAULT 300
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static int enabled = 0;
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static int refresh_interval;
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struct refresh_info {
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struct entry_list *entries;
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int verbose;
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unsigned int regex_present:1;
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regex_t filter;
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};
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static struct refresh_info master_refresh_info = {
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.entries = &entry_list,
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.verbose = 0,
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};
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struct ast_dnsmgr_entry *ast_dnsmgr_get(const char *name, struct in_addr *result)
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{
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struct ast_dnsmgr_entry *entry;
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if (!name || !result || ast_strlen_zero(name))
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return NULL;
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entry = calloc(1, sizeof(*result) + strlen(name));
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if (!entry)
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return NULL;
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entry->result = result;
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strcpy(entry->name, name);
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AST_LIST_LOCK(&entry_list);
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AST_LIST_INSERT_HEAD(&entry_list, entry, list);
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AST_LIST_UNLOCK(&entry_list);
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return entry;
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}
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void ast_dnsmgr_release(struct ast_dnsmgr_entry *entry)
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{
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if (!entry)
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return;
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AST_LIST_LOCK(&entry_list);
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AST_LIST_REMOVE(&entry_list, entry, list);
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AST_LIST_UNLOCK(&entry_list);
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free(entry);
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}
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int ast_dnsmgr_lookup(const char *name, struct in_addr *result, struct ast_dnsmgr_entry **dnsmgr)
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{
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if (!name || ast_strlen_zero(name) || !result || !dnsmgr)
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return -1;
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if (*dnsmgr && !strcasecmp((*dnsmgr)->name, name))
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return 0;
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if (option_verbose > 3)
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ast_verbose(VERBOSE_PREFIX_3 "doing lookup for '%s'\n", name);
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/* if it's actually an IP address and not a name,
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there's no need for a managed lookup */
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if (inet_aton(name, result))
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return 0;
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/* if the manager is disabled, do a direct lookup and return the result,
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otherwise register a managed lookup for the name */
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if (!enabled) {
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struct ast_hostent ahp;
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struct hostent *hp;
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if ((hp = ast_gethostbyname(name, &ahp)))
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memcpy(result, hp->h_addr, sizeof(result));
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return 0;
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} else {
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if (option_verbose > 2)
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ast_verbose(VERBOSE_PREFIX_2 "adding manager for '%s'\n", name);
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*dnsmgr = ast_dnsmgr_get(name, result);
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return !*dnsmgr;
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}
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}
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static void *do_refresh(void *data)
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{
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for (;;) {
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pthread_testcancel();
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usleep(ast_sched_wait(sched));
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pthread_testcancel();
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ast_sched_runq(sched);
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}
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return NULL;
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}
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static int refresh_list(void *data)
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{
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struct refresh_info *info = data;
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struct ast_dnsmgr_entry *entry;
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struct ast_hostent ahp;
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struct hostent *hp;
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/* if a refresh or reload is already in progress, exit now */
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if (ast_mutex_trylock(&refresh_lock)) {
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if (info->verbose)
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ast_log(LOG_WARNING, "DNS Manager refresh already in progress.\n");
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return -1;
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}
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if (option_verbose > 2)
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ast_verbose(VERBOSE_PREFIX_2 "Refreshing DNS lookups.\n");
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AST_LIST_LOCK(info->entries);
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AST_LIST_TRAVERSE(info->entries, entry, list) {
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if (info->regex_present && regexec(&info->filter, entry->name, 0, NULL, 0))
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continue;
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if (info->verbose && (option_verbose > 2))
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ast_verbose(VERBOSE_PREFIX_2 "refreshing '%s'\n", entry->name);
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if ((hp = ast_gethostbyname(entry->name, &ahp))) {
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/* check to see if it has changed, do callback if requested */
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memcpy(entry->result, hp->h_addr, sizeof(entry->result));
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}
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}
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AST_LIST_UNLOCK(info->entries);
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ast_mutex_unlock(&refresh_lock);
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/* automatically reschedule */
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return -1;
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}
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static int do_reload(int loading);
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static int handle_cli_reload(int fd, int argc, char *argv[])
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{
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if (argc > 2)
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return RESULT_SHOWUSAGE;
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do_reload(0);
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return 0;
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}
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static int handle_cli_refresh(int fd, int argc, char *argv[])
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{
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struct refresh_info info = {
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.entries = &entry_list,
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.verbose = 1,
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};
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if (argc > 3)
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return RESULT_SHOWUSAGE;
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if (argc == 3) {
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if (regcomp(&info.filter, argv[2], REG_EXTENDED | REG_NOSUB))
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return RESULT_SHOWUSAGE;
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else
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info.regex_present = 1;
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}
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refresh_list(&info);
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if (info.regex_present)
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regfree(&info.filter);
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return 0;
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}
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static int handle_cli_status(int fd, int argc, char *argv[])
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{
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int count = 0;
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struct ast_dnsmgr_entry *entry;
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if (argc > 2)
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return RESULT_SHOWUSAGE;
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ast_cli(fd, "DNS Manager: %s\n", enabled ? "enabled" : "disabled");
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ast_cli(fd, "Refresh Interval: %d seconds\n", refresh_interval);
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AST_LIST_LOCK(&entry_list);
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AST_LIST_TRAVERSE(&entry_list, entry, list)
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count++;
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AST_LIST_UNLOCK(&entry_list);
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ast_cli(fd, "Number of entries: %d\n", count);
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return 0;
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}
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static struct ast_cli_entry cli_reload = {
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.cmda = { "dnsmgr", "reload", NULL },
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.handler = handle_cli_reload,
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.summary = "Reloads the DNS manager configuration",
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.usage =
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"Usage: dnsmgr reload\n"
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" Reloads the DNS manager configuration.\n"
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};
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static struct ast_cli_entry cli_refresh = {
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.cmda = { "dnsmgr", "refresh", NULL },
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.handler = handle_cli_refresh,
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.summary = "Performs an immediate refresh",
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.usage =
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"Usage: dnsmgr refresh [pattern]\n"
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" Peforms an immediate refresh of the managed DNS entries.\n"
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" Optional regular expression pattern is used to filter the entries to refresh.\n",
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};
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static struct ast_cli_entry cli_status = {
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.cmda = { "dnsmgr", "status", NULL },
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.handler = handle_cli_status,
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.summary = "Display the DNS manager status",
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.usage =
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"Usage: dnsmgr status\n"
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" Displays the DNS manager status.\n"
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};
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int dnsmgr_init(void)
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{
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sched = sched_context_create();
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if (!sched) {
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ast_log(LOG_ERROR, "Unable to create schedule context.\n");
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return -1;
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}
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AST_LIST_HEAD_INIT(&entry_list);
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ast_cli_register(&cli_reload);
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ast_cli_register(&cli_status);
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return do_reload(1);
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}
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void dnsmgr_reload(void)
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{
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do_reload(0);
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}
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static int do_reload(int loading)
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{
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struct ast_config *config;
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const char *interval_value;
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const char *enabled_value;
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int interval;
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int was_enabled;
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pthread_attr_t attr;
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int res = -1;
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/* ensure that no refresh cycles run while the reload is in progress */
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ast_mutex_lock(&refresh_lock);
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/* reset defaults in preparation for reading config file */
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refresh_interval = REFRESH_DEFAULT;
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was_enabled = enabled;
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enabled = 0;
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if (refresh_sched > -1)
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ast_sched_del(sched, refresh_sched);
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if ((config = ast_config_load("dnsmgr.conf"))) {
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if ((enabled_value = ast_variable_retrieve(config, "general", "enable"))) {
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enabled = ast_true(enabled_value);
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}
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if ((interval_value = ast_variable_retrieve(config, "general", "refreshinterval"))) {
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if (sscanf(interval_value, "%d", &interval) < 1)
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ast_log(LOG_WARNING, "Unable to convert '%s' to a numeric value.\n", interval_value);
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else if (interval < 0)
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ast_log(LOG_WARNING, "Invalid refresh interval '%d' specified, using default\n", interval);
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else
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refresh_interval = interval;
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}
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ast_config_destroy(config);
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}
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if (enabled && refresh_interval) {
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refresh_sched = ast_sched_add(sched, refresh_interval * 1000, refresh_list, &master_refresh_info);
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ast_log(LOG_NOTICE, "Managed DNS entries will be refreshed every %d seconds.\n", refresh_interval);
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}
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/* if this reload enabled the manager, create the background thread
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if it does not exist */
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if (enabled && !was_enabled && (refresh_thread == AST_PTHREADT_NULL)) {
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pthread_attr_init(&attr);
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pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
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if (ast_pthread_create(&refresh_thread, &attr, do_refresh, NULL) < 0) {
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ast_log(LOG_ERROR, "Unable to start refresh thread.\n");
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ast_sched_del(sched, refresh_sched);
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}
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else {
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ast_cli_register(&cli_refresh);
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res = 0;
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}
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}
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/* if this reload disabled the manager and there is a background thread,
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kill it */
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else if (!enabled && was_enabled && (refresh_thread != AST_PTHREADT_NULL)) {
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/* wake up the thread so it will exit */
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pthread_cancel(refresh_thread);
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pthread_kill(refresh_thread, SIGURG);
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pthread_join(refresh_thread, NULL);
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refresh_thread = AST_PTHREADT_NULL;
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ast_cli_unregister(&cli_refresh);
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res = 0;
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}
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else
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res = 0;
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ast_mutex_unlock(&refresh_lock);
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return res;
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}
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