https://origsvn.digium.com/svn/asterisk/branches/1.4 ........ r69708 | file | 2007-06-18 12:51:36 -0400 (Mon, 18 Jun 2007) | 2 lines Remember the DNS lookup done when dnsmgr is called for the first time so that it does not needlessly spit out changed messages when the host really didn't change. ........ git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@69709 65c4cc65-6c06-0410-ace0-fbb531ad65f3
422 lines
11 KiB
C
422 lines
11 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 2005-2006, 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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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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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 Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*! \file
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*
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* \brief Background DNS update manager
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*
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* \author Kevin P. Fleming <kpfleming@digium.com>
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*/
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#include "asterisk.h"
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ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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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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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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/*! where we will store the resulting address */
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struct in_addr *result;
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/*! the last result, used to check if address has changed */
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struct in_addr last;
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/*! Set to 1 if the entry changes */
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int changed:1;
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ast_mutex_t lock;
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AST_RWLIST_ENTRY(ast_dnsmgr_entry) list;
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/*! just 1 here, but we use calloc to allocate the correct size */
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char name[1];
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};
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static AST_RWLIST_HEAD_STATIC(entry_list, ast_dnsmgr_entry);
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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;
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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 (!result || ast_strlen_zero(name) || !(entry = ast_calloc(1, sizeof(*entry) + strlen(name))))
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return NULL;
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entry->result = result;
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ast_mutex_init(&entry->lock);
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strcpy(entry->name, name);
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memcpy(&entry->last, result, sizeof(entry->last));
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AST_RWLIST_WRLOCK(&entry_list);
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AST_RWLIST_INSERT_HEAD(&entry_list, entry, list);
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AST_RWLIST_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_RWLIST_WRLOCK(&entry_list);
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AST_RWLIST_REMOVE(&entry_list, entry, list);
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AST_RWLIST_UNLOCK(&entry_list);
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if (option_verbose > 3)
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ast_verbose(VERBOSE_PREFIX_4 "removing dns manager for '%s'\n", entry->name);
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ast_mutex_destroy(&entry->lock);
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ast_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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struct ast_hostent ahp;
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struct hostent *hp;
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if (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_4 "doing dnsmgr_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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/* do a lookup now but add a manager so it will automagically get updated in the background */
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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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/* if dnsmgr is not enable don't bother adding an entry */
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if (!enabled)
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return 0;
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if (option_verbose > 2)
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ast_verbose(VERBOSE_PREFIX_2 "adding dns 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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* Refresh a dnsmgr entry
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*/
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static int dnsmgr_refresh(struct ast_dnsmgr_entry *entry, int verbose)
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{
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struct ast_hostent ahp;
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struct hostent *hp;
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char iabuf[INET_ADDRSTRLEN];
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char iabuf2[INET_ADDRSTRLEN];
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struct in_addr tmp;
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int changed = 0;
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ast_mutex_lock(&entry->lock);
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if (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 (where de callback is defined ????) */
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memcpy(&tmp, hp->h_addr, sizeof(tmp));
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if (tmp.s_addr != entry->last.s_addr) {
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ast_copy_string(iabuf, ast_inet_ntoa(entry->last), sizeof(iabuf));
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ast_copy_string(iabuf2, ast_inet_ntoa(tmp), sizeof(iabuf2));
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ast_log(LOG_NOTICE, "host '%s' changed from %s to %s\n",
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entry->name, iabuf, iabuf2);
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memcpy(entry->result, hp->h_addr, sizeof(entry->result));
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memcpy(&entry->last, hp->h_addr, sizeof(entry->last));
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changed = entry->changed = 1;
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}
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}
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ast_mutex_unlock(&entry->lock);
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return changed;
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}
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int ast_dnsmgr_refresh(struct ast_dnsmgr_entry *entry)
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{
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return dnsmgr_refresh(entry, 0);
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}
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/*
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* Check if dnsmgr entry has changed from since last call to this function
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*/
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int ast_dnsmgr_changed(struct ast_dnsmgr_entry *entry)
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{
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int changed;
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ast_mutex_lock(&entry->lock);
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changed = entry->changed;
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entry->changed = 0;
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ast_mutex_unlock(&entry->lock);
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return changed;
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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)*1000));
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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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/* 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_RWLIST_RDLOCK(info->entries);
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AST_RWLIST_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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dnsmgr_refresh(entry, info->verbose);
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}
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AST_RWLIST_UNLOCK(info->entries);
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ast_mutex_unlock(&refresh_lock);
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/* automatically reschedule based on the interval */
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return refresh_interval * 1000;
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}
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void dnsmgr_start_refresh(void)
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{
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if (refresh_sched > -1) {
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ast_sched_del(sched, refresh_sched);
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refresh_sched = ast_sched_add_variable(sched, 100, refresh_list, &master_refresh_info, 1);
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}
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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_RWLIST_RDLOCK(&entry_list);
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AST_RWLIST_TRAVERSE(&entry_list, entry, list)
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count++;
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AST_RWLIST_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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{ "dnsmgr", "reload", NULL },
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handle_cli_reload, "Reloads the DNS manager configuration",
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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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{ "dnsmgr", "refresh", NULL },
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handle_cli_refresh, "Performs an immediate refresh",
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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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{ "dnsmgr", "status", NULL },
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handle_cli_status, "Display the DNS manager status",
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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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if (!(sched = sched_context_create())) {
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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_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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int dnsmgr_reload(void)
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{
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return 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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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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ast_log(LOG_NOTICE, "Managed DNS entries will be refreshed every %d seconds.\n", refresh_interval);
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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) {
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if (!was_enabled && (refresh_thread == AST_PTHREADT_NULL)) {
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if (ast_pthread_create_background(&refresh_thread, NULL, do_refresh, NULL) < 0) {
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ast_log(LOG_ERROR, "Unable to start refresh thread.\n");
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}
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ast_cli_register(&cli_refresh);
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}
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/* make a background refresh happen right away */
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refresh_sched = ast_sched_add_variable(sched, 100, refresh_list, &master_refresh_info, 1);
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res = 0;
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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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