Sat Mar 24 23:28:30 2007

Asterisk developer's documentation


dnsmgr.c File Reference

Background DNS update manager. More...

#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.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"

Include dependency graph for dnsmgr.c:

Go to the source code of this file.

Data Structures

struct  ast_dnsmgr_entry

Defines

#define REFRESH_DEFAULT   300

Functions

ast_dnsmgr_entryast_dnsmgr_get (const char *name, struct in_addr *result)
int ast_dnsmgr_lookup (const char *name, struct in_addr *result, struct ast_dnsmgr_entry **dnsmgr)
void ast_dnsmgr_release (struct ast_dnsmgr_entry *entry)
static AST_LIST_HEAD (entry_list, ast_dnsmgr_entry)
int dnsmgr_init (void)
void dnsmgr_reload (void)
void dnsmgr_start_refresh (void)
static void * do_refresh (void *data)
static int do_reload (int loading)
static int handle_cli_refresh (int fd, int argc, char *argv[])
static int handle_cli_reload (int fd, int argc, char *argv[])
static int handle_cli_status (int fd, int argc, char *argv[])
static int refresh_list (void *data)

Variables

static struct ast_cli_entry cli_refresh
static struct ast_cli_entry cli_reload
static struct ast_cli_entry cli_status
static struct refresh_info master_refresh_info
static int refresh_sched = -1
static pthread_t refresh_thread = AST_PTHREADT_NULL
static struct sched_contextsched


Detailed Description

Background DNS update manager.

Definition in file dnsmgr.c.


Define Documentation

#define REFRESH_DEFAULT   300
 

Referenced by do_reload().


Function Documentation

struct ast_dnsmgr_entry* ast_dnsmgr_get const char *  name,
struct in_addr *  result
 

Definition at line 81 of file dnsmgr.c.

References AST_LIST_INSERT_HEAD, AST_LIST_LOCK, AST_LIST_UNLOCK, ast_strlen_zero(), calloc, and list.

Referenced by ast_dnsmgr_lookup().

00082 {
00083    struct ast_dnsmgr_entry *entry;
00084 
00085    if (!result || ast_strlen_zero(name))
00086       return NULL;
00087 
00088    entry = calloc(1, sizeof(*entry) + strlen(name));
00089    if (!entry)
00090       return NULL;
00091 
00092    entry->result = result;
00093    strcpy(entry->name, name);
00094 
00095    AST_LIST_LOCK(&entry_list);
00096    AST_LIST_INSERT_HEAD(&entry_list, entry, list);
00097    AST_LIST_UNLOCK(&entry_list);
00098 
00099    return entry;
00100 }

int ast_dnsmgr_lookup const char *  name,
struct in_addr *  result,
struct ast_dnsmgr_entry **  dnsmgr
 

Definition at line 113 of file dnsmgr.c.

References ahp, ast_dnsmgr_get(), ast_gethostbyname(), ast_strlen_zero(), ast_verbose(), enabled, hp, option_verbose, VERBOSE_PREFIX_2, and VERBOSE_PREFIX_3.

Referenced by build_peer().

00114 {
00115    if (ast_strlen_zero(name) || !result || !dnsmgr)
00116       return -1;
00117 
00118    if (*dnsmgr && !strcasecmp((*dnsmgr)->name, name))
00119       return 0;
00120 
00121    if (option_verbose > 3)
00122       ast_verbose(VERBOSE_PREFIX_3 "doing lookup for '%s'\n", name);
00123 
00124    /* if it's actually an IP address and not a name,
00125       there's no need for a managed lookup */
00126    if (inet_aton(name, result))
00127       return 0;
00128 
00129    /* if the manager is disabled, do a direct lookup and return the result,
00130       otherwise register a managed lookup for the name */
00131    if (!enabled) {
00132       struct ast_hostent ahp;
00133       struct hostent *hp;
00134 
00135       if ((hp = ast_gethostbyname(name, &ahp)))
00136          memcpy(result, hp->h_addr, sizeof(result));
00137       return 0;
00138    } else {
00139       if (option_verbose > 2)
00140          ast_verbose(VERBOSE_PREFIX_2 "adding manager for '%s'\n", name);
00141       *dnsmgr = ast_dnsmgr_get(name, result);
00142       return !*dnsmgr;
00143    }
00144 }

void ast_dnsmgr_release struct ast_dnsmgr_entry entry  ) 
 

Definition at line 102 of file dnsmgr.c.

References AST_LIST_LOCK, AST_LIST_REMOVE, AST_LIST_UNLOCK, free, and list.

Referenced by sip_destroy_peer().

00103 {
00104    if (!entry)
00105       return;
00106 
00107    AST_LIST_LOCK(&entry_list);
00108    AST_LIST_REMOVE(&entry_list, entry, list);
00109    AST_LIST_UNLOCK(&entry_list);
00110    free(entry);
00111 }

static AST_LIST_HEAD   entry_list,
ast_dnsmgr_entry 
[static]
 

Definition at line 60 of file dnsmgr.c.

00069                     {
00070    struct entry_list *entries;
00071    int verbose;
00072    unsigned int regex_present:1;
00073    regex_t filter;
00074 };

int dnsmgr_init void   ) 
 

Definition at line 285 of file dnsmgr.c.

References ast_cli_register(), AST_LIST_HEAD_INIT, ast_log(), cli_reload, cli_status, do_reload(), LOG_ERROR, sched, and sched_context_create().

00286 {
00287    sched = sched_context_create();
00288    if (!sched) {
00289       ast_log(LOG_ERROR, "Unable to create schedule context.\n");
00290       return -1;
00291    }
00292    AST_LIST_HEAD_INIT(&entry_list);
00293    ast_cli_register(&cli_reload);
00294    ast_cli_register(&cli_status);
00295    return do_reload(1);
00296 }

void dnsmgr_reload void   ) 
 

Definition at line 298 of file dnsmgr.c.

References do_reload().

Referenced by ast_module_reload().

00299 {
00300    do_reload(0);
00301 }

void dnsmgr_start_refresh void   ) 
 

Definition at line 194 of file dnsmgr.c.

References ast_sched_add_variable(), ast_sched_del(), master_refresh_info, refresh_list(), and sched.

00195 {
00196    if (refresh_sched > -1) {
00197       ast_sched_del(sched, refresh_sched);
00198       refresh_sched = ast_sched_add_variable(sched, 100, refresh_list, &master_refresh_info, 1);
00199    }
00200 }

static void* do_refresh void *  data  )  [static]
 

Definition at line 146 of file dnsmgr.c.

References ast_sched_runq(), ast_sched_wait(), and sched.

Referenced by do_reload().

00147 {
00148    for (;;) {
00149       pthread_testcancel();
00150       usleep(ast_sched_wait(sched));
00151       pthread_testcancel();
00152       ast_sched_runq(sched);
00153    }
00154    return NULL;
00155 }

static int do_reload int  loading  )  [static]
 

Definition at line 303 of file dnsmgr.c.

References ast_cli_register(), ast_cli_unregister(), ast_config_destroy(), ast_config_load(), ast_log(), ast_mutex_lock(), ast_mutex_unlock(), ast_pthread_create, AST_PTHREADT_NULL, ast_sched_add_variable(), ast_sched_del(), ast_true(), ast_variable_retrieve(), cli_refresh, config, do_refresh(), enabled, LOG_ERROR, LOG_NOTICE, LOG_WARNING, master_refresh_info, REFRESH_DEFAULT, refresh_list(), and sched.

00304 {
00305    struct ast_config *config;
00306    const char *interval_value;
00307    const char *enabled_value;
00308    int interval;
00309    int was_enabled;
00310    int res = -1;
00311 
00312    /* ensure that no refresh cycles run while the reload is in progress */
00313    ast_mutex_lock(&refresh_lock);
00314 
00315    /* reset defaults in preparation for reading config file */
00316    refresh_interval = REFRESH_DEFAULT;
00317    was_enabled = enabled;
00318    enabled = 0;
00319 
00320    if (refresh_sched > -1)
00321       ast_sched_del(sched, refresh_sched);
00322 
00323    if ((config = ast_config_load("dnsmgr.conf"))) {
00324       if ((enabled_value = ast_variable_retrieve(config, "general", "enable"))) {
00325          enabled = ast_true(enabled_value);
00326       }
00327       if ((interval_value = ast_variable_retrieve(config, "general", "refreshinterval"))) {
00328          if (sscanf(interval_value, "%d", &interval) < 1)
00329             ast_log(LOG_WARNING, "Unable to convert '%s' to a numeric value.\n", interval_value);
00330          else if (interval < 0)
00331             ast_log(LOG_WARNING, "Invalid refresh interval '%d' specified, using default\n", interval);
00332          else
00333             refresh_interval = interval;
00334       }
00335       ast_config_destroy(config);
00336    }
00337 
00338    if (enabled && refresh_interval)
00339       ast_log(LOG_NOTICE, "Managed DNS entries will be refreshed every %d seconds.\n", refresh_interval);
00340 
00341    /* if this reload enabled the manager, create the background thread
00342       if it does not exist */
00343    if (enabled && !was_enabled && (refresh_thread == AST_PTHREADT_NULL)) {
00344       if (ast_pthread_create(&refresh_thread, NULL, do_refresh, NULL) < 0) {
00345          ast_log(LOG_ERROR, "Unable to start refresh thread.\n");
00346       }
00347       else {
00348          ast_cli_register(&cli_refresh);
00349          /* make a background refresh happen right away */
00350          refresh_sched = ast_sched_add_variable(sched, 100, refresh_list, &master_refresh_info, 1);
00351          res = 0;
00352       }
00353    }
00354    /* if this reload disabled the manager and there is a background thread,
00355       kill it */
00356    else if (!enabled && was_enabled && (refresh_thread != AST_PTHREADT_NULL)) {
00357       /* wake up the thread so it will exit */
00358       pthread_cancel(refresh_thread);
00359       pthread_kill(refresh_thread, SIGURG);
00360       pthread_join(refresh_thread, NULL);
00361       refresh_thread = AST_PTHREADT_NULL;
00362       ast_cli_unregister(&cli_refresh);
00363       res = 0;
00364    }
00365    else
00366       res = 0;
00367 
00368    ast_mutex_unlock(&refresh_lock);
00369 
00370    return res;
00371 }

static int handle_cli_refresh int  fd,
int  argc,
char *  argv[]
[static]
 

Definition at line 213 of file dnsmgr.c.

References refresh_list(), and RESULT_SHOWUSAGE.

00214 {
00215    struct refresh_info info = {
00216       .entries = &entry_list,
00217       .verbose = 1,
00218    };
00219 
00220    if (argc > 3)
00221       return RESULT_SHOWUSAGE;
00222 
00223    if (argc == 3) {
00224       if (regcomp(&info.filter, argv[2], REG_EXTENDED | REG_NOSUB))
00225          return RESULT_SHOWUSAGE;
00226       else
00227          info.regex_present = 1;
00228    }
00229 
00230    refresh_list(&info);
00231 
00232    if (info.regex_present)
00233       regfree(&info.filter);
00234 
00235    return 0;
00236 }

static int handle_cli_reload int  fd,
int  argc,
char *  argv[]
[static]
 

Definition at line 204 of file dnsmgr.c.

References do_reload(), and RESULT_SHOWUSAGE.

00205 {
00206    if (argc > 2)
00207       return RESULT_SHOWUSAGE;
00208 
00209    do_reload(0);
00210    return 0;
00211 }

static int handle_cli_status int  fd,
int  argc,
char *  argv[]
[static]
 

Definition at line 238 of file dnsmgr.c.

References ast_cli(), AST_LIST_LOCK, AST_LIST_TRAVERSE, AST_LIST_UNLOCK, enabled, list, and RESULT_SHOWUSAGE.

00239 {
00240    int count = 0;
00241    struct ast_dnsmgr_entry *entry;
00242 
00243    if (argc > 2)
00244       return RESULT_SHOWUSAGE;
00245 
00246    ast_cli(fd, "DNS Manager: %s\n", enabled ? "enabled" : "disabled");
00247    ast_cli(fd, "Refresh Interval: %d seconds\n", refresh_interval);
00248    AST_LIST_LOCK(&entry_list);
00249    AST_LIST_TRAVERSE(&entry_list, entry, list)
00250       count++;
00251    AST_LIST_UNLOCK(&entry_list);
00252    ast_cli(fd, "Number of entries: %d\n", count);
00253 
00254    return 0;
00255 }

static int refresh_list void *  data  )  [static]
 

Definition at line 157 of file dnsmgr.c.

References ahp, ast_gethostbyname(), AST_LIST_LOCK, AST_LIST_TRAVERSE, AST_LIST_UNLOCK, ast_log(), ast_mutex_trylock(), ast_mutex_unlock(), ast_verbose(), hp, list, LOG_WARNING, option_verbose, ast_dnsmgr_entry::result, and VERBOSE_PREFIX_2.

Referenced by dnsmgr_start_refresh(), do_reload(), and handle_cli_refresh().

00158 {
00159    struct refresh_info *info = data;
00160    struct ast_dnsmgr_entry *entry;
00161    struct ast_hostent ahp;
00162    struct hostent *hp;
00163 
00164    /* if a refresh or reload is already in progress, exit now */
00165    if (ast_mutex_trylock(&refresh_lock)) {
00166       if (info->verbose)
00167          ast_log(LOG_WARNING, "DNS Manager refresh already in progress.\n");
00168       return -1;
00169    }
00170 
00171    if (option_verbose > 2)
00172       ast_verbose(VERBOSE_PREFIX_2 "Refreshing DNS lookups.\n");
00173    AST_LIST_LOCK(info->entries);
00174    AST_LIST_TRAVERSE(info->entries, entry, list) {
00175       if (info->regex_present && regexec(&info->filter, entry->name, 0, NULL, 0))
00176           continue;
00177 
00178       if (info->verbose && (option_verbose > 2))
00179          ast_verbose(VERBOSE_PREFIX_2 "refreshing '%s'\n", entry->name);
00180 
00181       if ((hp = ast_gethostbyname(entry->name, &ahp))) {
00182          /* check to see if it has changed, do callback if requested */
00183          memcpy(entry->result, hp->h_addr, sizeof(entry->result));
00184       }
00185    }
00186    AST_LIST_UNLOCK(info->entries);
00187 
00188    ast_mutex_unlock(&refresh_lock);
00189 
00190    /* automatically reschedule based on the interval */
00191    return refresh_interval * 1000;
00192 }


Variable Documentation

struct ast_cli_entry cli_refresh [static]
 

Definition at line 266 of file dnsmgr.c.

Referenced by do_reload().

struct ast_cli_entry cli_reload [static]
 

Definition at line 257 of file dnsmgr.c.

Referenced by dnsmgr_init(), load_module(), and unload_module().

struct ast_cli_entry cli_status [static]
 

Definition at line 276 of file dnsmgr.c.

struct refresh_info master_refresh_info [static]
 

Initial value:

 {
   .entries = &entry_list,
   .verbose = 0,
}

Definition at line 76 of file dnsmgr.c.

Referenced by dnsmgr_start_refresh(), and do_reload().

int refresh_sched = -1 [static]
 

Definition at line 51 of file dnsmgr.c.

pthread_t refresh_thread = AST_PTHREADT_NULL [static]
 

Definition at line 52 of file dnsmgr.c.

struct sched_context* sched [static]
 

Definition at line 50 of file dnsmgr.c.


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