* Cleanup dnsmgr thread and CLI commands on exit. (issue ASTERISK-20649) Reported by: Corey Farrell Patches: dnsmgr-cleanup-1_8.patch (license #5909) patch uploaded by Corey Farrell dnsmgr-cleanup-10-11-trunk.patch (license #5909) patch uploaded by Corey Farrell Modified ........ Merged revisions 377704 from http://svn.asterisk.org/svn/asterisk/branches/1.8 ........ Merged revisions 377705 from http://svn.asterisk.org/svn/asterisk/branches/10 ........ Merged revisions 377706 from http://svn.asterisk.org/svn/asterisk/branches/11 git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@377707 65c4cc65-6c06-0410-ace0-fbb531ad65f3
521 lines
14 KiB
C
521 lines
14 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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* \bug There is a minor race condition. In the event that an IP address
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* of a dnsmgr managed host changes, there is the potential for the consumer
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* of that address to access the in_addr data at the same time that the dnsmgr
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* thread is in the middle of updating it to the new address.
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*/
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/*! \li \ref dnsmgr.c uses the configuration file \ref dnsmgr.conf
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* \addtogroup configuration_file Configuration Files
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*/
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/*!
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* \page dnsmgr.conf dnsmgr.conf
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* \verbinclude dnsmgr.conf.sample
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*/
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/*** MODULEINFO
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<support_level>core</support_level>
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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 "asterisk/_private.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/sched.h"
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#include "asterisk/cli.h"
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#include "asterisk/manager.h"
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#include "asterisk/acl.h"
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static struct ast_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 IP address and port number */
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struct ast_sockaddr *result;
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/*! SRV record to lookup, if provided. Composed of service, protocol, and domain name: _Service._Proto.Name */
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char *service;
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/*! Address family to filter DNS responses. */
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unsigned int family;
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/*! Set to 1 if the entry changes */
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unsigned int changed:1;
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/*! Data to pass back to update_func */
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void *data;
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/*! The callback function to execute on address update */
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dns_update_func update_func;
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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_family(const char *name, struct ast_sockaddr *result, const char *service, unsigned int family)
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{
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struct ast_dnsmgr_entry *entry;
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int total_size = sizeof(*entry) + strlen(name) + (service ? strlen(service) + 1 : 0);
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if (!result || ast_strlen_zero(name) || !(entry = ast_calloc(1, total_size))) {
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return NULL;
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}
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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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if (service) {
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entry->service = ((char *) entry) + sizeof(*entry) + strlen(name);
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strcpy(entry->service, service);
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}
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entry->family = family;
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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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struct ast_dnsmgr_entry *ast_dnsmgr_get(const char *name, struct ast_sockaddr *result, const char *service)
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{
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return ast_dnsmgr_get_family(name, result, service, 0);
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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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}
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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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ast_debug(6, "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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static int internal_dnsmgr_lookup(const char *name, struct ast_sockaddr *result, struct ast_dnsmgr_entry **dnsmgr, const char *service, dns_update_func func, void *data)
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{
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unsigned int family;
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if (ast_strlen_zero(name) || !result || !dnsmgr) {
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return -1;
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}
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if (*dnsmgr && !strcasecmp((*dnsmgr)->name, name)) {
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return 0;
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}
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/* Lookup address family filter. */
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family = result->ss.ss_family;
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/*
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* If it's actually an IP address and not a name, there's no
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* need for a managed lookup.
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*/
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if (ast_sockaddr_parse(result, name, PARSE_PORT_FORBID)) {
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return 0;
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}
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ast_debug(6, "doing dnsmgr_lookup for '%s'\n", name);
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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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ast_get_ip_or_srv(result, name, service);
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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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}
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ast_debug(6, "adding dns manager for '%s'\n", name);
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*dnsmgr = ast_dnsmgr_get_family(name, result, service, family);
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(*dnsmgr)->update_func = func;
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(*dnsmgr)->data = data;
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return !*dnsmgr;
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}
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int ast_dnsmgr_lookup(const char *name, struct ast_sockaddr *result, struct ast_dnsmgr_entry **dnsmgr, const char *service)
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{
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return internal_dnsmgr_lookup(name, result, dnsmgr, service, NULL, NULL);
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}
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int ast_dnsmgr_lookup_cb(const char *name, struct ast_sockaddr *result, struct ast_dnsmgr_entry **dnsmgr, const char *service, dns_update_func func, void *data)
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{
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return internal_dnsmgr_lookup(name, result, dnsmgr, service, func, data);
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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_sockaddr tmp = { .len = 0, };
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int changed = 0;
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ast_mutex_lock(&entry->lock);
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ast_debug(6, "refreshing '%s'\n", entry->name);
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tmp.ss.ss_family = entry->family;
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if (!ast_get_ip_or_srv(&tmp, entry->name, entry->service)) {
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if (!ast_sockaddr_port(&tmp)) {
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ast_sockaddr_set_port(&tmp, ast_sockaddr_port(entry->result));
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}
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if (ast_sockaddr_cmp(&tmp, entry->result)) {
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const char *old_addr = ast_strdupa(ast_sockaddr_stringify(entry->result));
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const char *new_addr = ast_strdupa(ast_sockaddr_stringify(&tmp));
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if (entry->update_func) {
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entry->update_func(entry->result, &tmp, entry->data);
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} else {
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ast_log(LOG_NOTICE, "dnssrv: host '%s' changed from %s to %s\n",
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entry->name, old_addr, new_addr);
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ast_sockaddr_copy(entry->result, &tmp);
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changed = entry->changed = 1;
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}
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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(const void *data)
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{
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struct refresh_info *info = (struct refresh_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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}
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return -1;
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}
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ast_debug(6, "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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}
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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 char *handle_cli_reload(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
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{
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switch (cmd) {
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case CLI_INIT:
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e->command = "dnsmgr reload";
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e->usage =
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"Usage: dnsmgr reload\n"
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" Reloads the DNS manager configuration.\n";
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return NULL;
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case CLI_GENERATE:
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return NULL;
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}
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if (a->argc > 2) {
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return CLI_SHOWUSAGE;
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}
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do_reload(0);
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return CLI_SUCCESS;
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}
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static char *handle_cli_refresh(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
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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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switch (cmd) {
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case CLI_INIT:
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e->command = "dnsmgr refresh";
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e->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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return NULL;
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case CLI_GENERATE:
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return NULL;
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}
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if (!enabled) {
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ast_cli(a->fd, "DNS Manager is disabled.\n");
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return 0;
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}
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if (a->argc > 3) {
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return CLI_SHOWUSAGE;
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}
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if (a->argc == 3) {
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if (regcomp(&info.filter, a->argv[2], REG_EXTENDED | REG_NOSUB)) {
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return CLI_SHOWUSAGE;
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} else {
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info.regex_present = 1;
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}
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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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}
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return CLI_SUCCESS;
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}
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static char *handle_cli_status(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
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{
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int count = 0;
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struct ast_dnsmgr_entry *entry;
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switch (cmd) {
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case CLI_INIT:
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e->command = "dnsmgr status";
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e->usage =
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"Usage: dnsmgr status\n"
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" Displays the DNS manager status.\n";
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return NULL;
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case CLI_GENERATE:
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return NULL;
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}
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if (a->argc > 2) {
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return CLI_SHOWUSAGE;
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}
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ast_cli(a->fd, "DNS Manager: %s\n", enabled ? "enabled" : "disabled");
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ast_cli(a->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(a->fd, "Number of entries: %d\n", count);
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return CLI_SUCCESS;
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}
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static struct ast_cli_entry cli_reload = AST_CLI_DEFINE(handle_cli_reload, "Reloads the DNS manager configuration");
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static struct ast_cli_entry cli_refresh = AST_CLI_DEFINE(handle_cli_refresh, "Performs an immediate refresh");
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static struct ast_cli_entry cli_status = AST_CLI_DEFINE(handle_cli_status, "Display the DNS manager status");
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static void dnsmgr_shutdown(void)
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{
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ast_cli_unregister(&cli_reload);
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ast_cli_unregister(&cli_status);
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ast_cli_unregister(&cli_refresh);
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/* Destroy refresh thread. */
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ast_mutex_lock(&refresh_lock);
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if (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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}
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ast_mutex_unlock(&refresh_lock);
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ast_sched_context_destroy(sched);
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}
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int dnsmgr_init(void)
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{
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if (!(sched = ast_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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ast_cli_register(&cli_refresh);
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ast_register_atexit(dnsmgr_shutdown);
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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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struct ast_variable *v;
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struct ast_flags config_flags = { loading ? 0 : CONFIG_FLAG_FILEUNCHANGED };
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int interval;
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int was_enabled;
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if ((config = ast_config_load2("dnsmgr.conf", "dnsmgr", config_flags)) == CONFIG_STATUS_FILEUNCHANGED) {
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return 0;
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}
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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 (config == CONFIG_STATUS_FILEMISSING || config == CONFIG_STATUS_FILEINVALID) {
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ast_mutex_unlock(&refresh_lock);
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return 0;
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}
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AST_SCHED_DEL(sched, refresh_sched);
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for (v = ast_variable_browse(config, "general"); v; v = v->next) {
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if (!strcasecmp(v->name, "enable")) {
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enabled = ast_true(v->value);
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} else if (!strcasecmp(v->name, "refreshinterval")) {
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if (sscanf(v->value, "%30d", &interval) < 1) {
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ast_log(LOG_WARNING, "Unable to convert '%s' to a numeric value.\n", v->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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}
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}
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ast_config_destroy(config);
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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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}
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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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}
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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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/* if this reload disabled the manager and there is a background thread, kill it */
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} 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;
|
|
}
|
|
|
|
ast_mutex_unlock(&refresh_lock);
|
|
manager_event(EVENT_FLAG_SYSTEM, "Reload", "Module: DNSmgr\r\nStatus: %s\r/nMessage: DNSmgr reload Requested\r\n", enabled ? "Enabled" : "Disabled");
|
|
|
|
return 0;
|
|
}
|