res_config_ldap.c

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/*
 * Asterisk -- A telephony toolkit for Linux.
 *
 * Copyright (C) 2005, Oxymium sarl
 * Manuel Guesdon <mguesdon@oxymium.net> - LDAP RealTime Driver Author/Adaptor
 *
 * Copyright (C) 2007, Digium, Inc.
 * Russell Bryant <russell@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 *
 */

/*! \file
 *
 * \brief ldap plugin for portable configuration engine (ARA)
 *
 * \author Mark Spencer <markster@digium.com>
 * \author Manuel Guesdon
 * \author Carl-Einar Thorner <cthorner@voicerd.com>
 * \author Russell Bryant <russell@digium.com>
 *
 * \extref OpenLDAP http://www.openldap.org
 */

/*** MODULEINFO
   <depend>ldap</depend>
   <support_level>extended</support_level>
 ***/

#include "asterisk.h"

#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdio.h>
#include <ldap.h>

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 332615 $")

#include "asterisk/channel.h"
#include "asterisk/logger.h"
#include "asterisk/config.h"
#include "asterisk/module.h"
#include "asterisk/lock.h"
#include "asterisk/options.h"
#include "asterisk/cli.h"
#include "asterisk/utils.h"
#include "asterisk/strings.h"
#include "asterisk/pbx.h"
#include "asterisk/linkedlists.h"

#define RES_CONFIG_LDAP_CONF "res_ldap.conf"
#define RES_CONFIG_LDAP_DEFAULT_BASEDN "asterisk"

AST_MUTEX_DEFINE_STATIC(ldap_lock);

static LDAP *ldapConn;
static char url[512];
static char user[512];
static char pass[512];
static char base_distinguished_name[512];
static int version;
static time_t connect_time;

static int parse_config(void);
static int ldap_reconnect(void);
static char *realtime_ldap_status(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a);

struct category_and_metric {
   const char *name;
   int metric;
   const char *variable_name;
   const char *variable_value;
   int var_metric; /*!< For organizing variables (particularly includes and switch statments) within a context */
};

/*! \brief Table configuration */
struct ldap_table_config {
   char *table_name;     /*!< table name */
   char *additional_filter;     /*!< additional filter   */
   struct ast_variable *attributes;  /*!< attribute names conversion */
   struct ast_variable *delimiters;  /*!< the current delimiter is semicolon, so we are not using this variable */
   AST_LIST_ENTRY(ldap_table_config) entry;
   /* TODO: Make proxies work */
};

/*! \brief Should be locked before using it */
static AST_LIST_HEAD_NOLOCK_STATIC(table_configs, ldap_table_config);
static struct ldap_table_config *base_table_config;
static struct ldap_table_config *static_table_config;

static struct ast_cli_entry ldap_cli[] = {
   AST_CLI_DEFINE(realtime_ldap_status, "Shows connection information for the LDAP RealTime driver"),
};

/*! \brief Create a new table_config */
static struct ldap_table_config *table_config_new(const char *table_name)
{
   struct ldap_table_config *p;

   if (!(p = ast_calloc(1, sizeof(*p))))
      return NULL;

   if (table_name) {
      if (!(p->table_name = ast_strdup(table_name))) {
         free(p);
         return NULL;
      }
   }

   return p;
}

/*! \brief Find a table_config - Should be locked before using it 
 *  \note This function assumes ldap_lock to be locked. */
static struct ldap_table_config *table_config_for_table_name(const char *table_name)
{
   struct ldap_table_config *c = NULL;

   AST_LIST_TRAVERSE(&table_configs, c, entry) {
      if (!strcmp(c->table_name, table_name))
         break;
   }

   return c;
}

/*! \brief Find variable by name */
static struct ast_variable *variable_named(struct ast_variable *var, const char *name)
{
   for (; var; var = var->next) {
      if (!strcasecmp(name, var->name))
         break;
   }

   return var;
}

/*! \brief for the semicolon delimiter
   \param somestr - pointer to a string

   \return number of occurances of the delimiter(semicolon)
 */
static int semicolon_count_str(const char *somestr)
{
   int count = 0;

   for (; *somestr; somestr++) {
      if (*somestr == ';')
         count++;
   }

   return count;
}

/* takes a linked list of \a ast_variable variables, finds the one with the name variable_value
 * and returns the number of semicolons in the value for that \a ast_variable
 */
static int semicolon_count_var(struct ast_variable *var)
{
   struct ast_variable *var_value = variable_named(var, "variable_value");

   if (!var_value) {
      return 0;
   }

   ast_debug(2, "LINE(%d) semicolon_count_var: %s\n", __LINE__, var_value->value);

   return semicolon_count_str(var_value->value);
}

/*! \brief add attribute to table config - Should be locked before using it */
static void ldap_table_config_add_attribute(struct ldap_table_config *table_config,
   const char *attribute_name, const char *attribute_value)
{
   struct ast_variable *var;

   if (ast_strlen_zero(attribute_name) || ast_strlen_zero(attribute_value)) {
      return;
   }

   if (!(var = ast_variable_new(attribute_name, attribute_value, table_config->table_name))) {
      return;
   }

   if (table_config->attributes) {
      var->next = table_config->attributes;
   }
   table_config->attributes = var;
}

/*! \brief Free table_config 
 *  \note assumes ldap_lock to be locked */
static void table_configs_free(void)
{
   struct ldap_table_config *c;

   while ((c = AST_LIST_REMOVE_HEAD(&table_configs, entry))) {
      if (c->table_name) {
         ast_free(c->table_name);
      }
      if (c->additional_filter) {
         ast_free(c->additional_filter);
      }
      if (c->attributes) {
         ast_variables_destroy(c->attributes);
      }
      free(c);
   }

   base_table_config = NULL;
   static_table_config = NULL;
}

/*! \brief Convert variable name to ldap attribute name - Should be locked before using it */
static const char *convert_attribute_name_to_ldap(struct ldap_table_config *table_config,
   const char *attribute_name)
{
   int i = 0;
   struct ldap_table_config *configs[] = { table_config, base_table_config };

   for (i = 0; i < ARRAY_LEN(configs); i++) {
      struct ast_variable *attribute;

      if (!configs[i]) {
         continue;
      }

      attribute = configs[i]->attributes;
      for (; attribute; attribute = attribute->next) {
         if (!strcasecmp(attribute_name, attribute->name)) {
            return attribute->value;
         }
      }
   }

   return attribute_name;
}

/*! \brief Convert ldap attribute name to variable name 
   \note Should be locked before using it */
static const char *convert_attribute_name_from_ldap(struct ldap_table_config *table_config,
                      const char *attribute_name)
{
   int i = 0;
   struct ldap_table_config *configs[] = { table_config, base_table_config };

   for (i = 0; i < ARRAY_LEN(configs); i++) {
      struct ast_variable *attribute;

      if (!configs[i]) {
         continue;
      }

      attribute = configs[i]->attributes;
      for (; attribute; attribute = attribute->next) {
         if (strcasecmp(attribute_name, attribute->value) == 0) {
            return attribute->name;
         }
      }
   }

   return attribute_name;
}

/*! \brief Get variables from ldap entry attributes 
   \note Should be locked before using it
   \return a linked list of ast_variable variables.
 */
static struct ast_variable *realtime_ldap_entry_to_var(struct ldap_table_config *table_config,
   LDAPMessage *ldap_entry)
{
   BerElement *ber = NULL;
   struct ast_variable *var = NULL;
   struct ast_variable *prev = NULL;
   int is_delimited = 0;
   int i = 0;
   char *ldap_attribute_name;
   struct berval *value;
   int pos = 0;

   ldap_attribute_name = ldap_first_attribute(ldapConn, ldap_entry, &ber);

   while (ldap_attribute_name) {
      struct berval **values = NULL;
      const char *attribute_name = convert_attribute_name_from_ldap(table_config, ldap_attribute_name);
      int is_realmed_password_attribute = strcasecmp(attribute_name, "md5secret") == 0;

      values = ldap_get_values_len(ldapConn, ldap_entry, ldap_attribute_name); /* these are freed at the end */
      if (values) {
         struct berval **v;
         char *valptr;

         for (v = values; *v; v++) {
            value = *v;
            valptr = value->bv_val;
            ast_debug(2, "LINE(%d) attribute_name: %s LDAP value: %s\n", __LINE__, attribute_name, valptr);
            if (is_realmed_password_attribute) {
               if (!strncasecmp(valptr, "{md5}", 5)) {
                  valptr += 5;
               }
               ast_debug(2, "md5: %s\n", valptr);
            }
            if (valptr) {
               /* ok, so looping through all delimited values except the last one (not, last character is not delimited...) */
               if (is_delimited) {
                  i = 0;
                  pos = 0;
                  while (!ast_strlen_zero(valptr + i)) {
                     if (valptr[i] == ';') {
                        valptr[i] = '\0';
                        if (prev) {
                           prev->next = ast_variable_new(attribute_name, &valptr[pos], table_config->table_name);
                           if (prev->next) {
                              prev = prev->next;
                           }
                        } else {
                           prev = var = ast_variable_new(attribute_name, &valptr[pos], table_config->table_name);
                        }
                        pos = i + 1;
                     }
                     i++;
                  }
               }
               /* for the last delimited value or if the value is not delimited: */
               if (prev) {
                  prev->next = ast_variable_new(attribute_name, &valptr[pos], table_config->table_name);
                  if (prev->next) {
                     prev = prev->next;
                  }
               } else {
                  prev = var = ast_variable_new(attribute_name, &valptr[pos], table_config->table_name);
               }
            }
         }
         ldap_value_free_len(values);
      }
      ldap_memfree(ldap_attribute_name);
      ldap_attribute_name = ldap_next_attribute(ldapConn, ldap_entry, ber);
   }
   ber_free(ber, 0);

   return var;
}

/*! \brief Get variables from ldap entry attributes - Should be locked before using it
 *
 * The results are freed outside this function so is the \a vars array.
 * 
 * \return \a vars - an array of ast_variable variables terminated with a null.
 **/
static struct ast_variable **realtime_ldap_result_to_vars(struct ldap_table_config *table_config,
   LDAPMessage *ldap_result_msg, unsigned int *entries_count_ptr)
{
   struct ast_variable **vars;
   int i = 0;
   int tot_count = 0;
   int entry_index = 0;
   LDAPMessage *ldap_entry = NULL;
   BerElement *ber = NULL;
   struct ast_variable *var = NULL;
   struct ast_variable *prev = NULL;
   int is_delimited = 0;
   char *delim_value = NULL;
   int delim_tot_count = 0;
   int delim_count = 0;

   /* First find the total count */
   ldap_entry = ldap_first_entry(ldapConn, ldap_result_msg);

   for (tot_count = 0; ldap_entry; tot_count++) { 
      struct ast_variable *tmp = realtime_ldap_entry_to_var(table_config, ldap_entry);
      tot_count += semicolon_count_var(tmp);
      ldap_entry = ldap_next_entry(ldapConn, ldap_entry);
      ast_variables_destroy(tmp);
   }

   if (entries_count_ptr) {
      *entries_count_ptr = tot_count;
   }

   /* Now that we have the total count we allocate space and create the variables
    * Remember that each element in vars is a linked list that points to realtime variable.
    * If the we are dealing with a static realtime variable we create a new element in the \a vars array for each delimited
    * value in \a variable_value; otherwise, we keep \a vars static and increase the length of the linked list of variables in the array element.
    * This memory must be freed outside of this function. */
   vars = ast_calloc(sizeof(struct ast_variable *), tot_count + 1);

   ldap_entry = ldap_first_entry(ldapConn, ldap_result_msg);

   i = 0;

   /* For each static realtime variable we may create several entries in the \a vars array if it's delimited */
   for (entry_index = 0; ldap_entry; ) {
      int pos = 0;
      delim_value = NULL;
      delim_tot_count = 0;
      delim_count = 0;

      do { /* while delim_count */

         /* Starting new static var */
         char *ldap_attribute_name = ldap_first_attribute(ldapConn, ldap_entry, &ber);
         struct berval *value;
         while (ldap_attribute_name) {
            const char *attribute_name = convert_attribute_name_from_ldap(table_config, ldap_attribute_name);
            int is_realmed_password_attribute = strcasecmp(attribute_name, "md5secret") == 0;
            struct berval **values = NULL;

            values = ldap_get_values_len(ldapConn, ldap_entry, ldap_attribute_name);
            if (values) {
               struct berval **v;
               char *valptr;

               for (v = values; *v; v++) {
                  value = *v;
                  valptr = value->bv_val;
                  if (is_realmed_password_attribute) {
                     if (strncasecmp(valptr, "{md5}", 5) == 0) {
                        valptr += 5;
                     }
                     ast_debug(2, "md5: %s\n", valptr);
                  }
                  if (valptr) {
                     if (delim_value == NULL && !is_realmed_password_attribute
                        && (static_table_config != table_config || strcmp(attribute_name, "variable_value") == 0)) {

                        delim_value = ast_strdup(valptr);

                        if ((delim_tot_count = semicolon_count_str(delim_value)) > 0) {
                           ast_debug(4, "LINE(%d) is delimited %d times: %s\n", __LINE__, delim_tot_count, delim_value);
                           is_delimited = 1;
                        }
                     }

                     if (is_delimited != 0 && !is_realmed_password_attribute
                        && (static_table_config != table_config || strcmp(attribute_name, "variable_value") == 0) ) {
                        /* for non-Static RealTime, first */

                        for (i = pos; !ast_strlen_zero(valptr + i); i++) {
                           ast_debug(4, "LINE(%d) DELIM pos: %d i: %d\n", __LINE__, pos, i);
                           if (delim_value[i] == ';') {
                              delim_value[i] = '\0';

                              ast_debug(2, "LINE(%d) DELIM - attribute_name: %s value: %s pos: %d\n", __LINE__, attribute_name, &delim_value[pos], pos);

                              if (prev) {
                                 prev->next = ast_variable_new(attribute_name, &delim_value[pos], table_config->table_name);
                                 if (prev->next) {
                                    prev = prev->next;
                                 }
                              } else {
                                 prev = var = ast_variable_new(attribute_name, &delim_value[pos], table_config->table_name);
                              }
                              pos = i + 1;

                              if (static_table_config == table_config) {
                                 break;
                              }
                           }
                        }
                        if (ast_strlen_zero(valptr + i)) {
                           ast_debug(4, "LINE(%d) DELIM pos: %d i: %d delim_count: %d\n", __LINE__, pos, i, delim_count);
                           /* Last delimited value */
                           ast_debug(4, "LINE(%d) DELIM - attribute_name: %s value: %s pos: %d\n", __LINE__, attribute_name, &delim_value[pos], pos);
                           if (prev) {
                              prev->next = ast_variable_new(attribute_name, &delim_value[pos], table_config->table_name);
                              if (prev->next) {
                                 prev = prev->next;
                              }
                           } else {
                              prev = var = ast_variable_new(attribute_name, &delim_value[pos], table_config->table_name);
                           }
                           /* Remembering to free memory */
                           is_delimited = 0;
                           pos = 0;
                        }
                        free(delim_value);
                        delim_value = NULL;

                        ast_debug(4, "LINE(%d) DELIM pos: %d i: %d\n", __LINE__, pos, i);
                     } else {
                        /* not delimited */
                        if (delim_value) {
                           free(delim_value);
                           delim_value = NULL;
                        }
                        ast_debug(2, "LINE(%d) attribute_name: %s value: %s\n", __LINE__, attribute_name, valptr);

                        if (prev) {
                           prev->next = ast_variable_new(attribute_name, valptr, table_config->table_name);
                           if (prev->next) {
                              prev = prev->next;
                           }
                        } else {
                           prev = var = ast_variable_new(attribute_name, valptr, table_config->table_name);
                        }
                     }
                  }
               } /*!< for (v = values; *v; v++) */
               ldap_value_free_len(values);
            }/*!< if (values) */
            ldap_memfree(ldap_attribute_name);
            ldap_attribute_name = ldap_next_attribute(ldapConn, ldap_entry, ber);
         } /*!< while (ldap_attribute_name) */
         ber_free(ber, 0);
         if (static_table_config == table_config) {
            if (option_debug > 2) {
               const struct ast_variable *tmpdebug = variable_named(var, "variable_name");
               const struct ast_variable *tmpdebug2 = variable_named(var, "variable_value");
               if (tmpdebug && tmpdebug2) {
                  ast_debug(3, "LINE(%d) Added to vars - %s = %s\n", __LINE__, tmpdebug->value, tmpdebug2->value);
               }
            }
            vars[entry_index++] = var;
            prev = NULL;
         }

         delim_count++;
      } while (delim_count <= delim_tot_count && static_table_config == table_config);

      if (static_table_config != table_config) {
         ast_debug(3, "LINE(%d) Added to vars - non static\n", __LINE__);

         vars[entry_index++] = var;
         prev = NULL;
      }
      ldap_entry = ldap_next_entry(ldapConn, ldap_entry);
   } /*!< end for loop over ldap_entry */

   return vars;
}


/*! \brief Check if we have a connection error */
static int is_ldap_connect_error(int err)
{
   return (err == LDAP_SERVER_DOWN || err == LDAP_TIMEOUT || err == LDAP_CONNECT_ERROR);
}

/*! \brief Get LDAP entry by dn and return attributes as variables  - Should be locked before using it 
   This is used for setting the default values of an object(i.e., with accountBaseDN)
*/
static struct ast_variable *ldap_loadentry(struct ldap_table_config *table_config,
                  const char *dn)
{
   if (!table_config) {
      ast_log(LOG_ERROR, "No table config\n");
      return NULL;
   } else {
      struct ast_variable **vars = NULL;
      struct ast_variable *var = NULL;
      int result = -1;
      LDAPMessage *ldap_result_msg = NULL;
      int tries = 0;

      ast_debug(2, "ldap_loadentry dn=%s\n", dn);

      do {
         result = ldap_search_ext_s(ldapConn, dn, LDAP_SCOPE_BASE,
                  "(objectclass=*)", NULL, 0, NULL, NULL, NULL, LDAP_NO_LIMIT, &ldap_result_msg);
         if (result != LDAP_SUCCESS && is_ldap_connect_error(result)) {
            ast_log(LOG_WARNING, "Failed to query directory. Try %d/3\n", tries + 1);
            tries++;
            if (tries < 3) {
               usleep(500000L * tries);
               if (ldapConn) {
                  ldap_unbind_ext_s(ldapConn, NULL, NULL);
                  ldapConn = NULL;
               }
               if (!ldap_reconnect()) {
                  break;
               }
            }
         }
      } while (result != LDAP_SUCCESS && tries < 3 && is_ldap_connect_error(result));

      if (result != LDAP_SUCCESS) {
         ast_log(LOG_WARNING, "Failed to query directory. Error: %s.\n", ldap_err2string(result));
         ast_debug(2, "dn=%s\n", dn);
         ast_mutex_unlock(&ldap_lock);
         return NULL;
      } else {
         int num_entry = 0;
         unsigned int *entries_count_ptr = NULL; /*!< not using this */

         if ((num_entry = ldap_count_entries(ldapConn, ldap_result_msg)) > 0) {
            ast_debug(3, "num_entry: %d\n", num_entry);

            vars = realtime_ldap_result_to_vars(table_config, ldap_result_msg, entries_count_ptr);
            if (num_entry > 1) {
               ast_log(LOG_NOTICE, "More than one entry for dn=%s. Take only 1st one\n", dn);
            }
         } else {
            ast_debug(2, "Could not find any entry dn=%s.\n", dn);
         }
      }
      ldap_msgfree(ldap_result_msg);

      /* Chopping \a vars down to one variable */
      if (vars != NULL) {
         struct ast_variable **p = vars;

         /* Only take the first one. */
         var = *vars;

         /* Destroy the rest. */
         while (*++p) {
            ast_variables_destroy(*p);
         }
         ast_free(vars);
      }

      return var;
   }
}

/*! \note caller should free returned pointer */
static char *substituted(struct ast_channel *channel, const char *string)
{
#define MAXRESULT 2048
   char *ret_string = NULL;

   if (!ast_strlen_zero(string)) {
      ret_string = ast_calloc(1, MAXRESULT);
      pbx_substitute_variables_helper(channel, string, ret_string, MAXRESULT - 1);
   }
   ast_debug(2, "substituted: string: '%s' => '%s' \n", string, ret_string);
   return ret_string;
}

/*! \note caller should free returned pointer */
static char *cleaned_basedn(struct ast_channel *channel, const char *basedn)
{
   char *cbasedn = NULL;
   if (basedn) {
      char *p = NULL;
      cbasedn = substituted(channel, basedn);
      if (*cbasedn == '"') {
         cbasedn++;
         if (!ast_strlen_zero(cbasedn)) {
            int len = strlen(cbasedn);
            if (cbasedn[len - 1] == '"')
               cbasedn[len - 1] = '\0';

         }
      }
      p = cbasedn;
      while (*p) {
         if (*p == '|')
            *p = ',';
         p++;
      }
   }
   ast_debug(2, "basedn: '%s' => '%s' \n", basedn, cbasedn);
   return cbasedn;
}

/*! \brief Replace <search> by <by> in string. 
   \note No check is done on string allocated size ! */
static int replace_string_in_string(char *string, const char *search, const char *by)
{
   int search_len = strlen(search);
   int by_len = strlen(by);
   int replaced = 0;
   char *p = strstr(string, search);

   if (p) {
      replaced = 1;
      while (p) {
         if (by_len == search_len) {
            memcpy(p, by, by_len);
         } else {
            memmove(p + by_len, p + search_len, strlen(p + search_len) + 1);
            memcpy(p, by, by_len);
         }
         p = strstr(p + by_len, search);
      }
   }
   return replaced;
}

/*! \brief Append a name=value filter string. The filter string can grow. */
static void append_var_and_value_to_filter(struct ast_str **filter,
   struct ldap_table_config *table_config,
   const char *name, const char *value)
{
   char *new_name = NULL;
   char *new_value = NULL;
   char *like_pos = strstr(name, " LIKE");

   ast_debug(2, "name='%s' value='%s'\n", name, value);

   if (like_pos) {
      int len = like_pos - name;

      name = new_name = ast_strdupa(name);
      new_name[len] = '\0';
      value = new_value = ast_strdupa(value);
      replace_string_in_string(new_value, "\\_", "_");
      replace_string_in_string(new_value, "%", "*");
   }

   name = convert_attribute_name_to_ldap(table_config, name);

   ast_str_append(filter, 0, "(%s=%s)", name, value);
}

/*! \brief LDAP base function 
 * \return a null terminated array of ast_variable (one per entry) or NULL if no entry is found or if an error occured
 * caller should free the returned array and ast_variables
 * \param entries_count_ptr is a pointer to found entries count (can be NULL)
 * \param basedn is the base DN
 * \param table_name is the table_name (used dor attribute convertion and additional filter)
 * \param ap contains null terminated list of pairs name/value
*/
static struct ast_variable **realtime_ldap_base_ap(unsigned int *entries_count_ptr,
   const char *basedn, const char *table_name, va_list ap)
{
   struct ast_variable **vars = NULL;
   const char *newparam = NULL;
   const char *newval = NULL;
   struct ldap_table_config *table_config = NULL;
   char *clean_basedn = cleaned_basedn(NULL, basedn);
   struct ast_str *filter = NULL;
   int tries = 0;
   int result = 0;
   LDAPMessage *ldap_result_msg = NULL;

   if (!table_name) {
      ast_log(LOG_ERROR, "No table_name specified.\n");
      ast_free(clean_basedn);
      return NULL;
   } 

   if (!(filter = ast_str_create(80))) {
      ast_log(LOG_ERROR, "Can't initialize data structures.n");
      ast_free(clean_basedn);
      return NULL;
   }

   /* Get the first parameter and first value in our list of passed paramater/value pairs  */
   newparam = va_arg(ap, const char *);
   newval = va_arg(ap, const char *);

   if (!newparam || !newval) {
      ast_log(LOG_ERROR, "Realtime retrieval requires at least 1 parameter"
         " and 1 value to search on.\n");
      ast_free(filter);
      ast_free(clean_basedn);
      return NULL;
   }

   ast_mutex_lock(&ldap_lock);

   /* We now have our complete statement; Lets connect to the server and execute it.  */
   if (!ldap_reconnect()) {
      ast_mutex_unlock(&ldap_lock);
      ast_free(filter);
      ast_free(clean_basedn);
      return NULL;
   }

   table_config = table_config_for_table_name(table_name);
   if (!table_config) {
      ast_log(LOG_WARNING, "No table named '%s'.\n", table_name);
      ast_mutex_unlock(&ldap_lock);
      ast_free(filter);
      ast_free(clean_basedn);
      return NULL;
   }

   ast_str_append(&filter, 0, "(&");

   if (table_config && table_config->additional_filter) {
      ast_str_append(&filter, 0, "%s", table_config->additional_filter);
   }
   if (table_config != base_table_config && base_table_config && 
      base_table_config->additional_filter) {
      ast_str_append(&filter, 0, "%s", base_table_config->additional_filter);
   }

   /* Create the first part of the query using the first parameter/value pairs we just extracted */
   /*   If there is only 1 set, then we have our query. Otherwise, loop thru the list and concat */

   append_var_and_value_to_filter(&filter, table_config, newparam, newval);
   while ((newparam = va_arg(ap, const char *))) {
      newval = va_arg(ap, const char *);
      append_var_and_value_to_filter(&filter, table_config, newparam, newval);
   }
   ast_str_append(&filter, 0, ")");

   do {
      /* freeing ldap_result further down */
      result = ldap_search_ext_s(ldapConn, clean_basedn,
              LDAP_SCOPE_SUBTREE, ast_str_buffer(filter), NULL, 0, NULL, NULL, NULL, LDAP_NO_LIMIT,
              &ldap_result_msg);
      if (result != LDAP_SUCCESS && is_ldap_connect_error(result)) {
         ast_debug(1, "Failed to query directory. Try %d/10\n", tries + 1);
         if (++tries < 10) {
            usleep(1);
            if (ldapConn) {
               ldap_unbind_ext_s(ldapConn, NULL, NULL);
               ldapConn = NULL;
            }
            if (!ldap_reconnect()) {
               break;
            }
         }
      }
   } while (result != LDAP_SUCCESS && tries < 10 && is_ldap_connect_error(result));

   if (result != LDAP_SUCCESS) {
      ast_log(LOG_WARNING, "Failed to query directory. Error: %s.\n", ldap_err2string(result));
      ast_log(LOG_WARNING, "Query: %s\n", ast_str_buffer(filter));
   } else {
      /* this is where we create the variables from the search result 
       * freeing this \a vars outside this function */
      if (ldap_count_entries(ldapConn, ldap_result_msg) > 0) {
         /* is this a static var or some other? they are handled different for delimited values */
         vars = realtime_ldap_result_to_vars(table_config, ldap_result_msg, entries_count_ptr);
      } else {
         ast_debug(1, "Could not find any entry matching %s in base dn %s.\n", ast_str_buffer(filter), clean_basedn);
      }

      ldap_msgfree(ldap_result_msg);

      /* TODO: get the default variables from the accountBaseDN, not implemented with delimited values */
      if (vars) {
         struct ast_variable **p = vars;
         while (*p) {
            struct ast_variable *append_var = NULL;
            struct ast_variable *tmp = *p;
            while (tmp) {
               if (strcasecmp(tmp->name, "accountBaseDN") == 0) {
                  /* Get the variable to compare with for the defaults */
                  struct ast_variable *base_var = ldap_loadentry(table_config, tmp->value);
                  
                  while (base_var) {
                     struct ast_variable *next = base_var->next;
                     struct ast_variable *test_var = *p;
                     int base_var_found = 0;

                     /* run throught the default values and fill it inn if it is missing */
                     while (test_var) {
                        if (strcasecmp(test_var->name, base_var->name) == 0) {
                           base_var_found = 1;
                           break;
                        } else {
                           test_var = test_var->next;
                        }
                     }
                     if (base_var_found) {
                        base_var->next = NULL;
                        ast_variables_destroy(base_var);
                        base_var = next;
                     } else {
                        /*!
                         * \todo XXX The interactions with base_var and append_var may
                         * cause a memory leak of base_var nodes.  Also the append_var
                         * list and base_var list may get cross linked.
                         */
                        if (append_var) {
                           base_var->next = append_var;
                        } else {
                           base_var->next = NULL;
                        }
                        append_var = base_var;
                        base_var = next;
                     }
                  }
               }
               if (!tmp->next && append_var) {
                  tmp->next = append_var;
                  tmp = NULL;
               } else {
                  tmp = tmp->next;
               }
            }
            p++;
         }
      }
   }

   if (filter) {
      ast_free(filter);
   }

   if (clean_basedn) {
      ast_free(clean_basedn);
   }

   ast_mutex_unlock(&ldap_lock);

   return vars;
}

/*! \brief same as realtime_ldap_base_ap but take variable arguments count list */
static struct ast_variable **realtime_ldap_base(unsigned int *entries_count_ptr,
   const char *basedn, const char *table_name, ...)
{
   struct ast_variable **vars = NULL;
   va_list ap;

   va_start(ap, table_name);
   vars = realtime_ldap_base_ap(entries_count_ptr, basedn, table_name, ap);
   va_end(ap);

   return vars;
}

/*! \brief See Asterisk doc
*
* For Realtime Dynamic(i.e., switch, queues, and directory) -- I think
*/
static struct ast_variable *realtime_ldap(const char *basedn,
                 const char *table_name, va_list ap)
{
   struct ast_variable **vars = realtime_ldap_base_ap(NULL, basedn, table_name, ap);
   struct ast_variable *var = NULL;

   if (vars) {
      struct ast_variable *last_var = NULL;
      struct ast_variable **p = vars;

      /* Chain the vars array of lists into one list to return. */
      while (*p) {
         if (last_var) {
            while (last_var->next) {
               last_var = last_var->next;
            }
            last_var->next = *p;
         } else {
            var = *p;
            last_var = var;
         }
         p++;
      }
      free(vars);
   }
   return var;
}

/*! \brief See Asterisk doc
*
* this function will be called for the switch statment if no match is found with the realtime_ldap function(i.e. it is a failover);
* however, the ast_load_realtime wil match on wildcharacters also depending on what the mode is set to
* this is an area of asterisk that could do with a lot of modification
* I think this function returns Realtime dynamic objects
*/
static struct ast_config *realtime_multi_ldap(const char *basedn,
      const char *table_name, va_list ap)
{
   char *op;
   const char *initfield = NULL;
   const char *newparam, *newval;
   struct ast_variable **vars =
      realtime_ldap_base_ap(NULL, basedn, table_name, ap);
   struct ast_config *cfg = NULL;

   newparam = va_arg(ap, const char *);
   newval = va_arg(ap, const char *);
   if (!newparam || !newval) {
       ast_log(LOG_WARNING, "realtime retrieval requires at least 1 parameter and 1 value to search on.\n");
       return NULL;
   }
   initfield = ast_strdupa(newparam);
   if ((op = strchr(initfield, ' '))) {
      *op = '\0';
   }

   if (vars) {
      cfg = ast_config_new();
      if (!cfg) {
         ast_log(LOG_ERROR, "Unable to create a config!\n");
      } else {
         struct ast_variable **p = vars;

         while (*p) {
            struct ast_category *cat = NULL;
            cat = ast_category_new("", table_name, -1);
            if (!cat) {
               ast_log(LOG_ERROR, "Unable to create a new category!\n");
               break;
            } else {
               struct ast_variable *var = *p;
               while (var) {
                  struct ast_variable *next = var->next;
                  if (initfield && !strcmp(initfield, var->name)) {
                     ast_category_rename(cat, var->value);
                  }
                  var->next = NULL;
                  ast_variable_append(cat, var);
                  var = next;
               }
            }
            ast_category_append(cfg, cat);
            p++;
         }
      }
      free(vars);
   }
   return cfg;

}

/*! 
 * \brief Sorting alogrithm for qsort to find the order of the variables \a a and \a b
 * \param a pointer to category_and_metric struct
 * \param b pointer to category_and_metric struct
 *
 * \retval -1 for if b is greater
 * \retval 0 zero for equal
 * \retval 1 if a is greater
 */
static int compare_categories(const void *a, const void *b)
{
   const struct category_and_metric *as = a;
   const struct category_and_metric *bs = b;

   if (as->metric < bs->metric) {
      return -1;
   } else if (as->metric > bs->metric) {
      return 1;
   } else if (as->metric == bs->metric && strcmp(as->name, bs->name) != 0) {
      return strcmp(as->name, bs->name);
   } 
   /* if the metric and the category name is the same, we check the variable metric */
   if (as->var_metric < bs->var_metric) {
      return -1;
   } else if (as->var_metric > bs->var_metric) {
      return 1;
   }

   return 0;
}

/*! \brief See Asterisk doc
 *
*  This is for Static Realtime (again: I think...)
*  
*  load the configuration stuff for the .conf files
*  called on a reload
*/
static struct ast_config *config_ldap(const char *basedn, const char *table_name,
   const char *file, struct ast_config *cfg, struct ast_flags config_flags, const char *sugg_incl, const char *who_asked)
{
   unsigned int vars_count = 0;
   struct ast_variable **vars;
   int i = 0;
   struct ast_variable *new_v = NULL;
   struct ast_category *cur_cat = NULL;
   const char *last_category = NULL;
   int last_category_metric = 0;
   struct category_and_metric *categories;
   struct ast_variable **p;

   if (ast_strlen_zero(file) || !strcasecmp(file, RES_CONFIG_LDAP_CONF)) {
      ast_log(LOG_ERROR, "Missing configuration file: %s. Can't configure myself.\n", RES_CONFIG_LDAP_CONF);
      return NULL;
   }

   vars = realtime_ldap_base(&vars_count, basedn, table_name, "filename", file, "commented", "FALSE", NULL);

   if (!vars) {
      ast_log(LOG_WARNING, "Could not find config '%s' in directory.\n", file);
      return NULL;
   }

   /*!\note Since the items come back in random order, they need to be sorted
    * first, and since the data could easily exceed stack size, this is
    * allocated from the heap.
    */
   if (!(categories = ast_calloc(sizeof(*categories), vars_count))) {
      return NULL;
   }

   for (vars_count = 0, p = vars; *p; p++) {
      struct ast_variable *category = variable_named(*p, "category");
      struct ast_variable *cat_metric = variable_named(*p, "cat_metric");
      struct ast_variable *var_name = variable_named(*p, "variable_name");
      struct ast_variable *var_val = variable_named(*p, "variable_value");
      struct ast_variable *var_metric = variable_named(*p, "var_metric");
      struct ast_variable *dn = variable_named(*p, "dn");

      ast_debug(3, "category: %s\n", category->value);
      ast_debug(3, "var_name: %s\n", var_name->value);
      ast_debug(3, "var_val: %s\n", var_val->value);
      ast_debug(3, "cat_metric: %s\n", cat_metric->value);

      if (!category) {
         ast_log(LOG_ERROR, "No category name in entry '%s'  for file '%s'.\n",
               (dn ? dn->value : "?"), file);
      } else if (!cat_metric) {
         ast_log(LOG_ERROR, "No category metric in entry '%s'(category: %s) for file '%s'.\n",
               (dn ? dn->value : "?"), category->value, file);
      } else if (!var_metric) {
         ast_log(LOG_ERROR, "No variable metric in entry '%s'(category: %s) for file '%s'.\n",
               (dn ? dn->value : "?"), category->value, file);
      } else if (!var_name) {
         ast_log(LOG_ERROR, "No variable name in entry '%s' (category: %s metric: %s) for file '%s'.\n",
               (dn ? dn->value : "?"), category->value,
               cat_metric->value, file);
      } else if (!var_val) {
         ast_log(LOG_ERROR, "No variable value in entry '%s' (category: %s metric: %s variable: %s) for file '%s'.\n",
               (dn ? dn->value : "?"), category->value,
               cat_metric->value, var_name->value, file);
      } else {
         categories[vars_count].name = category->value;
         categories[vars_count].metric = atoi(cat_metric->value);
         categories[vars_count].variable_name = var_name->value;
         categories[vars_count].variable_value = var_val->value;
         categories[vars_count].var_metric = atoi(var_metric->value);
         vars_count++;
      }
   }

   qsort(categories, vars_count, sizeof(*categories), compare_categories);

   for (i = 0; i < vars_count; i++) {
      if (!strcmp(categories[i].variable_name, "#include")) {
         struct ast_flags flags = { 0 };
         if (!ast_config_internal_load(categories[i].variable_value, cfg, flags, "", who_asked)) {
            break;
         }
         continue;
      }

      if (!last_category || strcmp(last_category, categories[i].name) ||
         last_category_metric != categories[i].metric) {

         cur_cat = ast_category_new(categories[i].name, table_name, -1);
         if (!cur_cat) {
            break;
         }
         last_category = categories[i].name;
         last_category_metric = categories[i].metric;
         ast_category_append(cfg, cur_cat);
      }

      if (!(new_v = ast_variable_new(categories[i].variable_name, categories[i].variable_value, table_name))) {
         break;
      }

      ast_variable_append(cur_cat, new_v);
   }

   ast_free(vars);
   ast_free(categories);

   return cfg;
}

/* \brief Function to update a set of values in ldap static mode
*/
static int update_ldap(const char *basedn, const char *table_name, const char *attribute,
   const char *lookup, va_list ap)
{
   int error = 0;
   LDAPMessage *ldap_entry = NULL;
   LDAPMod **ldap_mods;
   const char *newparam = NULL;
   const char *newval = NULL;
   char *dn;
   int num_entries = 0;
   int i = 0;
   int mods_size = 0;
   int mod_exists = 0;
   struct ldap_table_config *table_config = NULL;
   char *clean_basedn = NULL;
   struct ast_str *filter = NULL;
   int tries = 0;
   int result = 0;
   LDAPMessage *ldap_result_msg = NULL;

   if (!table_name) {
      ast_log(LOG_ERROR, "No table_name specified.\n");
      return -1;
   } 

   if (!(filter = ast_str_create(80))) {
      return -1;
   }

   if (!attribute || !lookup) {
      ast_log(LOG_WARNING, "LINE(%d): search parameters are empty.\n", __LINE__);
      return -1;
   }
   ast_mutex_lock(&ldap_lock);

   /* We now have our complete statement; Lets connect to the server and execute it.  */
   if (!ldap_reconnect()) {
      ast_mutex_unlock(&ldap_lock);
      return -1;
   }

   table_config = table_config_for_table_name(table_name);
   if (!table_config) {
      ast_log(LOG_ERROR, "No table named '%s'.\n", table_name);
      ast_mutex_unlock(&ldap_lock);
      return -1;
   }

   clean_basedn = cleaned_basedn(NULL, basedn);

   /* Create the filter with the table additional filter and the parameter/value pairs we were given */
   ast_str_append(&filter, 0, "(&");
   if (table_config && table_config->additional_filter) {
      ast_str_append(&filter, 0, "%s", table_config->additional_filter);
   }
   if (table_config != base_table_config && base_table_config && base_table_config->additional_filter) {
      ast_str_append(&filter, 0, "%s", base_table_config->additional_filter);
   }
   append_var_and_value_to_filter(&filter, table_config, attribute, lookup);
   ast_str_append(&filter, 0, ")");

   /* Create the modification array with the parameter/value pairs we were given, 
    * if there are several parameters with the same name, we collect them into 
    * one parameter/value pair and delimit them with a semicolon */
   newparam = va_arg(ap, const char *);
   newparam = convert_attribute_name_to_ldap(table_config, newparam);
   newval = va_arg(ap, const char *);
   if (!newparam || !newval) {
      ast_log(LOG_WARNING, "LINE(%d): need at least one parameter to modify.\n", __LINE__);
      return -1;
   }

   mods_size = 2; /* one for the first param/value pair and one for the the terminating NULL */
   ldap_mods = ast_calloc(sizeof(LDAPMod *), mods_size);
   ldap_mods[0] = ast_calloc(1, sizeof(LDAPMod));

   ldap_mods[0]->mod_op = LDAP_MOD_REPLACE;
   ldap_mods[0]->mod_type = ast_strdup(newparam);

   ldap_mods[0]->mod_values = ast_calloc(sizeof(char *), 2);
   ldap_mods[0]->mod_values[0] = ast_strdup(newval);

   while ((newparam = va_arg(ap, const char *))) {
      newparam = convert_attribute_name_to_ldap(table_config, newparam);
      newval = va_arg(ap, const char *);
      mod_exists = 0;

      for (i = 0; i < mods_size - 1; i++) {
         if (ldap_mods[i]&& !strcmp(ldap_mods[i]->mod_type, newparam)) {
            /* We have the parameter allready, adding the value as a semicolon delimited value */
            ldap_mods[i]->mod_values[0] = ast_realloc(ldap_mods[i]->mod_values[0], sizeof(char) * (strlen(ldap_mods[i]->mod_values[0]) + strlen(newval) + 2));
            strcat(ldap_mods[i]->mod_values[0], ";");
            strcat(ldap_mods[i]->mod_values[0], newval);
            mod_exists = 1;   
            break;
         }
      }

      /* create new mod */
      if (!mod_exists) {
         mods_size++;
         ldap_mods = ast_realloc(ldap_mods, sizeof(LDAPMod *) * mods_size);
         ldap_mods[mods_size - 1] = NULL;
         
         ldap_mods[mods_size - 2] = ast_calloc(1, sizeof(LDAPMod));

         ldap_mods[mods_size - 2]->mod_type = ast_calloc(sizeof(char), strlen(newparam) + 1);
         strcpy(ldap_mods[mods_size - 2]->mod_type, newparam);

         if (strlen(newval) == 0) {
            ldap_mods[mods_size - 2]->mod_op = LDAP_MOD_DELETE;
         } else {
            ldap_mods[mods_size - 2]->mod_op = LDAP_MOD_REPLACE;

            ldap_mods[mods_size - 2]->mod_values = ast_calloc(sizeof(char *), 2);
            ldap_mods[mods_size - 2]->mod_values[0] = ast_calloc(sizeof(char), strlen(newval) + 1);
            strcpy(ldap_mods[mods_size - 2]->mod_values[0], newval);
         }
      }
   }
   /* freeing ldap_mods further down */

   do {
      /* freeing ldap_result further down */
      result = ldap_search_ext_s(ldapConn, clean_basedn,
              LDAP_SCOPE_SUBTREE, ast_str_buffer(filter), NULL, 0, NULL, NULL, NULL, LDAP_NO_LIMIT,
              &ldap_result_msg);
      if (result != LDAP_SUCCESS && is_ldap_connect_error(result)) {
         ast_log(LOG_WARNING, "Failed to query directory. Try %d/3\n", tries + 1);
         tries++;
         if (tries < 3) {
            usleep(500000L * tries);
            if (ldapConn) {
               ldap_unbind_ext_s(ldapConn, NULL, NULL);
               ldapConn = NULL;
            }
            if (!ldap_reconnect())
               break;
         }
      }
   } while (result != LDAP_SUCCESS && tries < 3 && is_ldap_connect_error(result));

   if (result != LDAP_SUCCESS) {
      ast_log(LOG_WARNING, "Failed to query directory. Error: %s.\n", ldap_err2string(result));
      ast_log(LOG_WARNING, "Query: %s\n", ast_str_buffer(filter));

      ast_mutex_unlock(&ldap_lock);
      free(filter);
      free(clean_basedn);
      ldap_msgfree(ldap_result_msg);
      ldap_mods_free(ldap_mods, 0);
      return -1;
   }
   /* Ready to update */
   if ((num_entries = ldap_count_entries(ldapConn, ldap_result_msg)) > 0) {
      ast_debug(3, "LINE(%d) Modifying %s=%s hits: %d\n", __LINE__, attribute, lookup, num_entries);
      for (i = 0; option_debug > 2 && i < mods_size - 1; i++) {
         if (ldap_mods[i]->mod_op != LDAP_MOD_DELETE) {
            ast_debug(3, "LINE(%d) %s=%s \n", __LINE__, ldap_mods[i]->mod_type, ldap_mods[i]->mod_values[0]);
         } else {
            ast_debug(3, "LINE(%d) deleting %s \n", __LINE__, ldap_mods[i]->mod_type);
         }
      }
      ldap_entry = ldap_first_entry(ldapConn, ldap_result_msg);

      for (i = 0; ldap_entry; i++) { 
         dn = ldap_get_dn(ldapConn, ldap_entry);
         if ((error = ldap_modify_ext_s(ldapConn, dn, ldap_mods, NULL, NULL)) != LDAP_SUCCESS)  {
            ast_log(LOG_ERROR, "Couldn't modify '%s'='%s', dn:%s because %s\n",
                  attribute, lookup, dn, ldap_err2string(error));
         }
         ldap_memfree(dn);
         ldap_entry = ldap_next_entry(ldapConn, ldap_entry);
      }
   }

   ast_mutex_unlock(&ldap_lock);
   ast_free(filter);
   ast_free(clean_basedn);
   ldap_msgfree(ldap_result_msg);
   ldap_mods_free(ldap_mods, 0);
   return num_entries;
}

static int update2_ldap(const char *basedn, const char *table_name, va_list ap)
{
   int error = 0;
   LDAPMessage *ldap_entry = NULL;
   LDAPMod **ldap_mods;
   const char *newparam = NULL;
   const char *newval = NULL;
   char *dn;
   int num_entries = 0;
   int i = 0;
   int mods_size = 0;
   int mod_exists = 0;
   struct ldap_table_config *table_config = NULL;
   char *clean_basedn = NULL;
   struct ast_str *filter = NULL;
   int tries = 0;
   int result = 0;
   LDAPMessage *ldap_result_msg = NULL;

   if (!table_name) {
      ast_log(LOG_ERROR, "No table_name specified.\n");
      return -1;
   } 

   if (!(filter = ast_str_create(80))) {
      return -1;
   }

   ast_mutex_lock(&ldap_lock);

   /* We now have our complete statement; Lets connect to the server and execute it.  */
   if (!ldap_reconnect()) {
      ast_mutex_unlock(&ldap_lock);
      ast_free(filter);
      return -1;
   }

   table_config = table_config_for_table_name(table_name);
   if (!table_config) {
      ast_log(LOG_ERROR, "No table named '%s'.\n", table_name);
      ast_mutex_unlock(&ldap_lock);
      ast_free(filter);
      return -1;
   }

   clean_basedn = cleaned_basedn(NULL, basedn);

   /* Create the filter with the table additional filter and the parameter/value pairs we were given */
   ast_str_append(&filter, 0, "(&");
   if (table_config && table_config->additional_filter) {
      ast_str_append(&filter, 0, "%s", table_config->additional_filter);
   }
   if (table_config != base_table_config && base_table_config
      && base_table_config->additional_filter) {
      ast_str_append(&filter, 0, "%s", base_table_config->additional_filter);
   }

   /* Get multiple lookup keyfields and values */
   while ((newparam = va_arg(ap, const char *))) {
      newval = va_arg(ap, const char *);
      append_var_and_value_to_filter(&filter, table_config, newparam, newval);
   }
   ast_str_append(&filter, 0, ")");

   /* Create the modification array with the parameter/value pairs we were given, 
    * if there are several parameters with the same name, we collect them into 
    * one parameter/value pair and delimit them with a semicolon */
   newparam = va_arg(ap, const char *);
   newparam = convert_attribute_name_to_ldap(table_config, newparam);
   newval = va_arg(ap, const char *);
   if (!newparam || !newval) {
      ast_log(LOG_WARNING, "LINE(%d): need at least one parameter to modify.\n", __LINE__);
      ast_free(filter);
      ast_free(clean_basedn);
      return -1;
   }

   mods_size = 2; /* one for the first param/value pair and one for the the terminating NULL */
   ldap_mods = ast_calloc(sizeof(LDAPMod *), mods_size);
   ldap_mods[0] = ast_calloc(1, sizeof(LDAPMod));

   ldap_mods[0]->mod_op = LDAP_MOD_REPLACE;
   ldap_mods[0]->mod_type = ast_calloc(sizeof(char), strlen(newparam) + 1);
   strcpy(ldap_mods[0]->mod_type, newparam);

   ldap_mods[0]->mod_values = ast_calloc(sizeof(char), 2);
   ldap_mods[0]->mod_values[0] = ast_calloc(sizeof(char), strlen(newval) + 1);
   strcpy(ldap_mods[0]->mod_values[0], newval);

   while ((newparam = va_arg(ap, const char *))) {
      newparam = convert_attribute_name_to_ldap(table_config, newparam);
      newval = va_arg(ap, const char *);
      mod_exists = 0;

      for (i = 0; i < mods_size - 1; i++) {
         if (ldap_mods[i]&& !strcmp(ldap_mods[i]->mod_type, newparam)) {
            /* We have the parameter allready, adding the value as a semicolon delimited value */
            ldap_mods[i]->mod_values[0] = ast_realloc(ldap_mods[i]->mod_values[0], sizeof(char) * (strlen(ldap_mods[i]->mod_values[0]) + strlen(newval) + 2));
            strcat(ldap_mods[i]->mod_values[0], ";");
            strcat(ldap_mods[i]->mod_values[0], newval);
            mod_exists = 1;   
            break;
         }
      }

      /* create new mod */
      if (!mod_exists) {
         mods_size++;
         ldap_mods = ast_realloc(ldap_mods, sizeof(LDAPMod *) * mods_size);
         ldap_mods[mods_size - 1] = NULL;
         ldap_mods[mods_size - 2] = ast_calloc(1, sizeof(LDAPMod));

         ldap_mods[mods_size - 2]->mod_op = LDAP_MOD_REPLACE;

         ldap_mods[mods_size - 2]->mod_type = ast_calloc(sizeof(char), strlen(newparam) + 1);
         strcpy(ldap_mods[mods_size - 2]->mod_type, newparam);

         ldap_mods[mods_size - 2]->mod_values = ast_calloc(sizeof(char *), 2);
         ldap_mods[mods_size - 2]->mod_values[0] = ast_calloc(sizeof(char), strlen(newval) + 1);
         strcpy(ldap_mods[mods_size - 2]->mod_values[0], newval);
      }
   }
   /* freeing ldap_mods further down */

   do {
      /* freeing ldap_result further down */
      result = ldap_search_ext_s(ldapConn, clean_basedn,
              LDAP_SCOPE_SUBTREE, ast_str_buffer(filter), NULL, 0, NULL, NULL, NULL, LDAP_NO_LIMIT,
              &ldap_result_msg);
      if (result != LDAP_SUCCESS && is_ldap_connect_error(result)) {
         ast_log(LOG_WARNING, "Failed to query directory. Try %d/3\n", tries + 1);
         tries++;
         if (tries < 3) {
            usleep(500000L * tries);
            if (ldapConn) {
               ldap_unbind_ext_s(ldapConn, NULL, NULL);
               ldapConn = NULL;
            }
            if (!ldap_reconnect()) {
               break;
            }
         }
      }
   } while (result != LDAP_SUCCESS && tries < 3 && is_ldap_connect_error(result));

   if (result != LDAP_SUCCESS) {
      ast_log(LOG_WARNING, "Failed to query directory. Error: %s.\n", ldap_err2string(result));
      ast_log(LOG_WARNING, "Query: %s\n", ast_str_buffer(filter));

      ast_mutex_unlock(&ldap_lock);
      ast_free(filter);
      ast_free(clean_basedn);
      ldap_msgfree(ldap_result_msg);
      ldap_mods_free(ldap_mods, 0);
      return -1;
   }
   /* Ready to update */
   if ((num_entries = ldap_count_entries(ldapConn, ldap_result_msg)) > 0) {
      for (i = 0; option_debug > 2 && i < mods_size - 1; i++) {
         ast_debug(3, "LINE(%d) %s=%s \n", __LINE__, ldap_mods[i]->mod_type, ldap_mods[i]->mod_values[0]);
      }

      ldap_entry = ldap_first_entry(ldapConn, ldap_result_msg);

      for (i = 0; ldap_entry; i++) {
         dn = ldap_get_dn(ldapConn, ldap_entry);
         if ((error = ldap_modify_ext_s(ldapConn, dn, ldap_mods, NULL, NULL)) != LDAP_SUCCESS)  {
            ast_log(LOG_ERROR, "Couldn't modify dn:%s because %s", dn, ldap_err2string(error));
         }
         ldap_memfree(dn);
         ldap_entry = ldap_next_entry(ldapConn, ldap_entry);
      }
   }

   ast_mutex_unlock(&ldap_lock);
   if (filter) {
      ast_free(filter);
   }
   if (clean_basedn) {
      ast_free(clean_basedn);
   }
   ldap_msgfree(ldap_result_msg);
   ldap_mods_free(ldap_mods, 0);
   return num_entries;
}

static struct ast_config_engine ldap_engine = {
   .name = "ldap",
   .load_func = config_ldap,
   .realtime_func = realtime_ldap,
   .realtime_multi_func = realtime_multi_ldap,
   .update_func = update_ldap,
   .update2_func = update2_ldap,
};

static int load_module(void)
{
   if (parse_config() < 0) {
      ast_log(LOG_ERROR, "Cannot load LDAP RealTime driver.\n");
      return 0;
   }

   ast_mutex_lock(&ldap_lock);

   if (!ldap_reconnect())  {
      ast_log(LOG_WARNING, "Couldn't establish connection to LDAP directory. Check debug.\n");
   }

   ast_config_engine_register(&ldap_engine);
   ast_verb(1, "LDAP RealTime driver loaded.\n");
   ast_cli_register_multiple(ldap_cli, ARRAY_LEN(ldap_cli));

   ast_mutex_unlock(&ldap_lock);

   return 0;
}

static int unload_module(void)
{
   /* Aquire control before doing anything to the module itself. */
   ast_mutex_lock(&ldap_lock);

   table_configs_free();

   if (ldapConn) {
      ldap_unbind_ext_s(ldapConn, NULL, NULL);
      ldapConn = NULL;
   }
   ast_cli_unregister_multiple(ldap_cli, ARRAY_LEN(ldap_cli));
   ast_config_engine_deregister(&ldap_engine);
   ast_verb(1, "LDAP RealTime driver unloaded.\n");

   /* Unlock so something else can destroy the lock. */
   ast_mutex_unlock(&ldap_lock);

   return 0;
}

static int reload(void)
{
   /* Aquire control before doing anything to the module itself. */
   ast_mutex_lock(&ldap_lock);

   if (ldapConn) {
      ldap_unbind_ext_s(ldapConn, NULL, NULL);
      ldapConn = NULL;
   }

   if (parse_config() < 0) {
      ast_log(LOG_NOTICE, "Cannot reload LDAP RealTime driver.\n");
      ast_mutex_unlock(&ldap_lock);
      return 0;
   }     

   if (!ldap_reconnect())  {
      ast_log(LOG_WARNING, "Couldn't establish connection to your directory server. Check debug.\n");
   }

   ast_verb(2, "LDAP RealTime driver reloaded.\n");

   /* Done reloading. Release lock so others can now use driver. */
   ast_mutex_unlock(&ldap_lock);

   return 0;
}

/*! \brief parse the configuration file */
static int parse_config(void)
{
   struct ast_config *config;
   struct ast_flags config_flags = {0};
   const char *s, *host;
   int port;
   char *category_name = NULL;

   /* Make sure that global variables are reset */
   url[0] = '\0';
   user[0] = '\0';
   pass[0] = '\0';
   base_distinguished_name[0] = '\0';
   version = 3;

   config = ast_config_load(RES_CONFIG_LDAP_CONF, config_flags);
   if (config == CONFIG_STATUS_FILEMISSING || config == CONFIG_STATUS_FILEINVALID) {
      ast_log(LOG_ERROR, "Cannot load configuration file: %s\n", RES_CONFIG_LDAP_CONF);
      return -1;
   }

   if (!(s = ast_variable_retrieve(config, "_general", "user"))) {
      ast_log(LOG_NOTICE, "No directory user found, anonymous binding as default.\n");
      user[0] = '\0';
   } else {
      ast_copy_string(user, s, sizeof(user));
   }

   if (!ast_strlen_zero(user)) {
      if (!(s = ast_variable_retrieve(config, "_general", "pass"))) {
         ast_log(LOG_WARNING, "No directory password found, using 'asterisk' as default.\n");
         ast_copy_string(pass, "asterisk", sizeof(pass));
      } else {
         ast_copy_string(pass, s, sizeof(pass));
      }
   }

   /* URL is preferred, use host and port if not found */
   if ((s = ast_variable_retrieve(config, "_general", "url"))) {
      ast_copy_string(url, s, sizeof(url));
   } else if ((host = ast_variable_retrieve(config, "_general", "host"))) {
      if (!(s = ast_variable_retrieve(config, "_general", "port")) || sscanf(s, "%5d", &port) != 1 || port > 65535) {
         ast_log(LOG_NOTICE, "No directory port found, using 389 as default.\n");
         port = 389;
      }

      snprintf(url, sizeof(url), "ldap://%s:%d", host, port);
   } else {
      ast_log(LOG_ERROR, "No directory URL or host found.\n");
      ast_config_destroy(config);
      return -1;
   }

   if (!(s = ast_variable_retrieve(config, "_general", "basedn"))) {
      ast_log(LOG_ERROR, "No LDAP base dn found, using '%s' as default.\n", RES_CONFIG_LDAP_DEFAULT_BASEDN);
      ast_copy_string(base_distinguished_name, RES_CONFIG_LDAP_DEFAULT_BASEDN, sizeof(base_distinguished_name));
   } else 
      ast_copy_string(base_distinguished_name, s, sizeof(base_distinguished_name));

   if (!(s = ast_variable_retrieve(config, "_general", "version")) && !(s = ast_variable_retrieve(config, "_general", "protocol"))) {
      ast_log(LOG_NOTICE, "No explicit LDAP version found, using 3 as default.\n");
   } else if (sscanf(s, "%30d", &version) != 1 || version < 1 || version > 6) {
      ast_log(LOG_WARNING, "Invalid LDAP version '%s', using 3 as default.\n", s);
      version = 3;
   }

   table_configs_free();

   while ((category_name = ast_category_browse(config, category_name))) {
      int is_general = (strcasecmp(category_name, "_general") == 0);
      int is_config = (strcasecmp(category_name, "config") == 0); /*!< using the [config] context for Static RealTime */
      struct ast_variable *var = ast_variable_browse(config, category_name);
      
      if (var) {
         struct ldap_table_config *table_config =
            table_config_for_table_name(category_name);
         if (!table_config) {
            table_config = table_config_new(category_name);
            AST_LIST_INSERT_HEAD(&table_configs, table_config, entry);
            if (is_general)
               base_table_config = table_config;
            if (is_config)
               static_table_config = table_config;
         }
         for (; var; var = var->next) {
            if (!strcasecmp(var->name, "additionalFilter")) {
               table_config->additional_filter = ast_strdup(var->value);
            } else {
               ldap_table_config_add_attribute(table_config, var->name, var->value);
            }
         }
      }
   }

   ast_config_destroy(config);

   return 1;
}

/*! \note ldap_lock should have been locked before calling this function. */
static int ldap_reconnect(void)
{
   int bind_result = 0;
   struct berval cred;

   if (ldapConn) {
      ast_debug(2, "Everything seems fine.\n");
      return 1;
   }

   if (ast_strlen_zero(url)) {
      ast_log(LOG_ERROR, "Not enough parameters to connect to ldap directory\n");
      return 0;
   }

   if (LDAP_SUCCESS != ldap_initialize(&ldapConn, url)) {
      ast_log(LOG_ERROR, "Failed to init ldap connection to '%s'. Check debug for more info.\n", url);
      return 0;
   }

   if (LDAP_OPT_SUCCESS != ldap_set_option(ldapConn, LDAP_OPT_PROTOCOL_VERSION, &version)) {
      ast_log(LOG_WARNING, "Unable to set LDAP protocol version to %d, falling back to default.\n", version);
   }

   if (!ast_strlen_zero(user)) {
      ast_debug(2, "bind to '%s' as user '%s'\n", url, user);
      cred.bv_val = (char *) pass;
      cred.bv_len = strlen(pass);
      bind_result = ldap_sasl_bind_s(ldapConn, user, LDAP_SASL_SIMPLE, &cred, NULL, NULL, NULL);
   } else {
      ast_debug(2, "bind %s anonymously\n", url);
      cred.bv_val = NULL;
      cred.bv_len = 0;
      bind_result = ldap_sasl_bind_s(ldapConn, NULL, LDAP_SASL_SIMPLE, &cred, NULL, NULL, NULL);
   }
   if (bind_result == LDAP_SUCCESS) {
      ast_debug(2, "Successfully connected to directory.\n");
      connect_time = time(NULL);
      return 1;
   } else {
      ast_log(LOG_WARNING, "bind failed: %s\n", ldap_err2string(bind_result));
      ldap_unbind_ext_s(ldapConn, NULL, NULL);
      ldapConn = NULL;
      return 0;
   }
}

static char *realtime_ldap_status(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   char status[256], credentials[100] = "";
   int ctimesec = time(NULL) - connect_time;

   switch (cmd) {
   case CLI_INIT:
      e->command = "realtime show ldap status";
      e->usage =
         "Usage: realtime show ldap status\n"
         "         Shows connection information for the LDAP RealTime driver\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (!ldapConn)
      return CLI_FAILURE;

   if (!ast_strlen_zero(url)) 
      snprintf(status, sizeof(status), "Connected to '%s', baseDN %s", url, base_distinguished_name);

   if (!ast_strlen_zero(user))
      snprintf(credentials, sizeof(credentials), " with username %s", user);

   if (ctimesec > 31536000) {
      ast_cli(a->fd, "%s%s for %d years, %d days, %d hours, %d minutes, %d seconds.\n",
            status, credentials, ctimesec / 31536000,
            (ctimesec % 31536000) / 86400, (ctimesec % 86400) / 3600,
            (ctimesec % 3600) / 60, ctimesec % 60);
   } else if (ctimesec > 86400) {
      ast_cli(a->fd, "%s%s for %d days, %d hours, %d minutes, %d seconds.\n",
            status, credentials, ctimesec / 86400, (ctimesec % 86400) / 3600,
            (ctimesec % 3600) / 60, ctimesec % 60);
   } else if (ctimesec > 3600) {
      ast_cli(a->fd, "%s%s for %d hours, %d minutes, %d seconds.\n",
            status, credentials, ctimesec / 3600, (ctimesec % 3600) / 60,
            ctimesec % 60);
   } else if (ctimesec > 60) {
      ast_cli(a->fd, "%s%s for %d minutes, %d seconds.\n", status, credentials,
               ctimesec / 60, ctimesec % 60);
   } else {
      ast_cli(a->fd, "%s%s for %d seconds.\n", status, credentials, ctimesec);
   }

   return CLI_SUCCESS;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "LDAP realtime interface",
   .load = load_module,
   .unload = unload_module,
   .reload = reload,
   .load_pri = AST_MODPRI_REALTIME_DRIVER,
);