userblacklist.c

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/*
 * $Id: userblacklist.c 5227 2008-11-19 13:16:15Z henningw $
 *
 * Copyright (C) 2007 1&1 Internet AG
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*!
 * \file
 * \brief USERBLACKLIST :: module definitions
 * \ingroup userblacklist
 * - Module: \ref userblacklist
 */

/*!
 * \defgroup userblacklist USERBLACKLIST :: The Kamailio userblacklist Module
 *
 * The userblacklist module allows Kamailio to handle blacklists on a per user basis.
 * This information is stored in a database table, which is queried to decide if the
 * number (more exactly, the request URI user) is blacklisted or not.
 * An additional functionality that this module provides is the ability to handle
 * global blacklists. This lists are loaded on startup into memory, thus providing a
 * better performance then in the userblacklist case.
 */

#include <string.h>

#include "../../parser/parse_uri.h"
#include "../../mem/shm_mem.h"
#include "../../sr_module.h"
#include "../../mi/mi.h"
#include "../../mem/mem.h"
#include "../../usr_avp.h"
#include "../../locking.h"
#include "../../error.h"
#include "../../ut.h"
#include "../../mod_fix.h"

#include "../../trie/dtrie.h"
#include "db.h"
#include "db_userblacklist.h"

MODULE_VERSION


#define MAXNUMBERLEN 31


typedef struct _avp_check
{
   int avp_flags;
   int_str avp_name;
} avp_check_t;


struct check_blacklist_fs_t {
  struct dtrie_node_t *dtrie_root;
};

str userblacklist_db_url = str_init(DEFAULT_RODB_URL);
static int use_domain   = 0;

/* ---- fixup functions: */
static int check_blacklist_fixup(void** param, int param_no);
static int check_user_blacklist_fixup(void** param, int param_no);

/* ---- exported commands: */
static int check_user_blacklist(struct sip_msg *msg, char* str1, char* str2, char* str3, char* str4);
static int check_blacklist(struct sip_msg *msg, struct check_blacklist_fs_t *arg1);

/* ---- module init functions: */
static int mod_init(void);
static int child_init(int rank);
static int mi_child_init(void);
static void mod_destroy(void);

/* --- fifo functions */
struct mi_root * mi_reload_blacklist(struct mi_root* cmd, void* param);  /* usage: kamctl fifo reload_blacklist */


static cmd_export_t cmds[]={
   { "check_user_blacklist", (cmd_function)check_user_blacklist, 2, check_user_blacklist_fixup, 0, REQUEST_ROUTE | FAILURE_ROUTE },
   { "check_user_blacklist", (cmd_function)check_user_blacklist, 3, check_user_blacklist_fixup, 0, REQUEST_ROUTE | FAILURE_ROUTE },
   { "check_user_blacklist", (cmd_function)check_user_blacklist, 4, check_user_blacklist_fixup, 0, REQUEST_ROUTE | FAILURE_ROUTE },
   { "check_blacklist", (cmd_function)check_blacklist, 1, check_blacklist_fixup, 0, REQUEST_ROUTE | FAILURE_ROUTE },
   { 0, 0, 0, 0, 0, 0}
};


static param_export_t params[] = {
   userblacklist_DB_URL
   userblacklist_DB_TABLE
   globalblacklist_DB_TABLE
   userblacklist_DB_COLS
   globalblacklist_DB_COLS
   { "use_domain",      INT_PARAM, &use_domain },
   { 0, 0, 0}
};


/* Exported MI functions */
static mi_export_t mi_cmds[] = {
   { "reload_blacklist", mi_reload_blacklist, MI_NO_INPUT_FLAG, 0, mi_child_init },
   { 0, 0, 0, 0, 0}
};


struct module_exports exports= {
   "userblacklist",
   DEFAULT_DLFLAGS,
   cmds,
   params,
   0,
   mi_cmds,
   0,
   0,
   mod_init,
   0,
   mod_destroy,
   child_init
};


struct source_t {
   struct source_t *next;
   /** prefixes to be used are stored in this table */
   char *table;
   /** d-tree structure: will be built from data in database */
   struct dtrie_node_t *dtrie_root;
};


struct source_list_t {
  struct source_t *head;
};


static gen_lock_t *lock = NULL;
static struct source_list_t *sources = NULL;
static struct dtrie_node_t *dtrie_root;


static int check_user_blacklist_fixup(void** param, int param_no)
{
   pv_elem_t *model=NULL;
   str s;

   /* convert to str */
   s.s = (char*)*param;
   s.len = strlen(s.s);

   if (param_no > 0 && param_no <= 4) {
      if(s.len == 0 && param_no != 4) {
         LM_ERR("no parameter %d\n", param_no);
         return E_UNSPEC;
      }

      if(pv_parse_format(&s, &model) < 0 || !model) {
         LM_ERR("wrong format [%.*s] for parameter %d\n", s.len, s.s, param_no);
         return E_UNSPEC;
      }

      if(!model->spec.getf) {
         if(param_no == 1) {
            if(str2int(&s, (unsigned int*)&model->spec.pvp.pvn.u.isname.name.n) != 0) {
               LM_ERR("wrong value [%.*s] for parameter %d\n", s.len, s.s, param_no);
               return E_UNSPEC;
            }
         } else {
            if(param_no == 2 || param_no == 3) {
               LM_ERR("wrong value [%.*s] for parameter %d\n", s.len, s.s, param_no);
               return E_UNSPEC;
            } else {
               // only a string
               return 0;
            }
         }
      }
      *param = (void*)model;
   } else {
      LM_ERR("wrong number of parameters\n");
   }

   return 0;
}


static int check_user_blacklist(struct sip_msg *msg, char* str1, char* str2, char* str3, char* str4)
{
   str user = { .len = 0, .s = NULL };
   str domain = { .len = 0, .s = NULL};
   str table = { .len = 0, .s = NULL};
   str number = { .len = 0, .s = NULL};

   void **nodeflags;
   char *ptr;
   char req_number[MAXNUMBERLEN+1];

   /* user */
   if(((pv_elem_p)str1)->spec.getf) {
      if(pv_printf_s(msg, (pv_elem_p)str1, &user) != 0) {
         LM_ERR("cannot print user pseudo-variable\n");
         return -1;
      }
   }
   /* domain */
   if(((pv_elem_p)str2)->spec.getf) {
      if(pv_printf_s(msg, (pv_elem_p)str2, &domain) != 0) {
         LM_ERR("cannot print domain pseudo-variable\n");
         return -1;
      }
   }
   /* source number */
   if(str3 != NULL && ((pv_elem_p)str3)->spec.getf) {
      if(pv_printf_s(msg, (pv_elem_p)str3, &number) != 0) {
         LM_ERR("cannot print number pseudo-variable\n");
         return -1;
      }
   }
   /* table name */
   if(str4 != NULL && strlen(str4) > 0) {
      /* string */
      table.s=str4;
      table.len=strlen(str4);
   } else {
      /* use default table name */
      table.len=userblacklist_table.len;
      table.s=userblacklist_table.s;
   }

   if (msg->first_line.type != SIP_REQUEST) {
      LM_ERR("SIP msg is not a request\n");
      return -1;
   }

   if(number.s == NULL) {
      /* use R-URI */
      if ((parse_sip_msg_uri(msg) < 0) || (!msg->parsed_uri.user.s) || (msg->parsed_uri.user.len > MAXNUMBERLEN)) {
         LM_ERR("cannot parse msg URI\n");
         return -1;
      }
      strncpy(req_number, msg->parsed_uri.user.s, msg->parsed_uri.user.len);
      req_number[msg->parsed_uri.user.len] = '\0';
   } else {
      if (number.len > MAXNUMBERLEN) {
         LM_ERR("number to long\n");
         return -1;
      }
      strncpy(req_number, number.s, number.len);
      req_number[number.len] = '\0';
   }

   LM_DBG("check entry %s for user %.*s on domain %.*s in table %.*s\n", req_number,
      user.len, user.s, domain.len, domain.s, table.len, table.s);
   if (db_build_userbl_tree(&user, &domain, &table, dtrie_root, use_domain) < 0) {
      LM_ERR("cannot build d-tree\n");
      return -1;
   }

   ptr = req_number;
   /* Skip over non-digits.  */
   while (strlen(ptr) > 0 && !isdigit(*ptr)) {
      ptr = ptr + 1;
   }

   nodeflags = dtrie_longest_match(dtrie_root, ptr, strlen(ptr), NULL, 10);
   if (nodeflags) {
      if (*nodeflags == (void *)MARK_WHITELIST) {
         /* LM_ERR("whitelisted"); */
         return 1; /* found, but is whitelisted */
      }
   } else {
      /* LM_ERR("not found"); */
      return 1; /* not found is ok */
   }

   LM_DBG("entry %s is blacklisted\n", req_number);
   return -1;
}


/**
 * Finds d-tree root for given table.
 * \return pointer to d-tree root on success, NULL otherwise
 */
static struct dtrie_node_t *table2dt(const char *table)
{
   struct source_t *src = sources->head;
   while (src) {
      if (strcmp(table, src->table) == 0) return src->dtrie_root;
      src = src->next;
   }

   LM_ERR("invalid table '%s'.\n", table);
   return NULL;
}


/**
 * Adds a new table to the list, if the table is
 * already present, nothing will be done.
 * \return zero on success, negative on errors
 */
static int add_source(const char *table)
{
   /* check if the table is already present */
   struct source_t *src = sources->head;
   while (src) {
      if (strcmp(table, src->table) == 0) return 0;
      src = src->next;
   }

   src = shm_malloc(sizeof(struct source_t));
   if (!src) {
      SHM_MEM_ERROR;
      return -1;
   }
   memset(src, 0, sizeof(struct source_t));

   src->next = sources->head;
   sources->head = src;

   src->table = shm_malloc(strlen(table)+1);
   if (!src->table) {
      SHM_MEM_ERROR;
      shm_free(src);
      return -1;
   }
   strcpy(src->table, table);
   LM_DBG("add table %s", table);

   src->dtrie_root = dtrie_init(10);

   if (src->dtrie_root == NULL) {
      LM_ERR("could not initialize data");
      return -1;
   }

   return 0;
}


static int check_blacklist_fixup(void **arg, int arg_no)
{
   char *table = (char *)(*arg);
   struct dtrie_node_t *node = NULL;
   if (arg_no != 1) {
      LM_ERR("wrong number of parameters\n");
      return -1;
   }

   if (!table) {
      LM_ERR("no table name\n");
      return -1;
   }
   /* try to add the table */
   if (add_source(table) != 0) {
      LM_ERR("could not add table");
      return -1;
   }  

   /* get the node that belongs to the table */
   node = table2dt(table);
   if (!node) {
      LM_ERR("invalid table '%s'\n", table);
      return -1;
   }

   struct check_blacklist_fs_t *new_arg = (struct check_blacklist_fs_t*)pkg_malloc(sizeof(struct check_blacklist_fs_t));
   if (!new_arg) {
      PKG_MEM_ERROR;
      return -1;
   }
   memset(new_arg, 0, sizeof(struct check_blacklist_fs_t));
   new_arg->dtrie_root = node;
   *arg=(void*)new_arg;

   return 0;
}


static int check_blacklist(struct sip_msg *msg, struct check_blacklist_fs_t *arg1)
{
   void **nodeflags;
   char *ptr;
   char req_number[MAXNUMBERLEN+1];
   int ret = -1;

   if (msg->first_line.type != SIP_REQUEST) {
      LM_ERR("SIP msg is not a request\n");
      return -1;
   }

   if (parse_sip_msg_uri(msg) < 0) {
      LM_ERR("cannot parse msg URI\n");
      return -1;
   }

   if ((parse_sip_msg_uri(msg) < 0) || (!msg->parsed_uri.user.s) || (msg->parsed_uri.user.len > MAXNUMBERLEN)) {
      LM_ERR("cannot parse msg URI\n");
      return -1;
   }
   strncpy(req_number, msg->parsed_uri.user.s, msg->parsed_uri.user.len);
   req_number[msg->parsed_uri.user.len] = '\0';

   ptr = req_number;
   /* Skip over non-digits.  */
   while (strlen(ptr) > 0 && !isdigit(*ptr)) {
      ptr = ptr + 1;
   }

   LM_DBG("check entry %s\n", req_number);

   /* avoids dirty reads when updating d-tree */
   lock_get(lock);
   nodeflags = dtrie_longest_match(arg1->dtrie_root, ptr, strlen(ptr), NULL, 10);
   if (nodeflags) {
      if (*nodeflags == (void *)MARK_WHITELIST) {
         /* LM_DBG("whitelisted"); */
         ret = 1; /* found, but is whitelisted */
      }
   }
   else {
      /* LM_ERR("not found"); */
      ret = 1; /* not found is ok */
   }
   lock_release(lock);

   LM_DBG("entry %s is blacklisted\n", req_number);
   return ret;
}


/**
 * Fills the d-tree for all configured and prepared sources.
 * \return 0 on success, -1 otherwise
 */
static int reload_sources(void)
{
   int result = 0;
   str tmp;

   /* critical section start: avoids dirty reads when updating d-tree */
   lock_get(lock);

   struct source_t *src = sources->head;
   while (src) {
      tmp.s = src->table;
      tmp.len = strlen(src->table);
      int n = db_reload_source(&tmp, src->dtrie_root);
      if (n < 0) {
         LM_ERR("cannot reload source from '%.*s'\n", tmp.len, tmp.s);
         result = -1;
         break;
      }
      LM_INFO("got %d entries from '%.*s'\n", n, tmp.len, tmp.s);
      src = src->next;
   }

   /* critical section end */
   lock_release(lock);

   return result;
}


static int init_source_list(void)
{
   sources = shm_malloc(sizeof(struct source_list_t));
   if (!sources) {
      SHM_MEM_ERROR;
      return -1;
   }
   sources->head = NULL;
   return 0;
}


static void destroy_source_list(void)
{
   if (sources) {
      while (sources->head) {
         struct source_t *src = sources->head;
         sources->head = src->next;

         if (src->table) shm_free(src->table);
         dtrie_destroy(&(src->dtrie_root), NULL, 10);
         shm_free(src);
      }

      shm_free(sources);
      sources = NULL;
   }
}


static int init_shmlock(void)
{
   lock = lock_alloc();
   if (!lock) {
      LM_CRIT("cannot allocate memory for lock.\n");
      return -1;
   }
   if (lock_init(lock) == 0) {
      LM_CRIT("cannot initialize lock.\n");
      return -1;
   }

   return 0;
}


static void destroy_shmlock(void)
{
   if (lock) {
      lock_destroy(lock);
      lock_dealloc((void *)lock);
      lock = NULL;
   }
}


struct mi_root * mi_reload_blacklist(struct mi_root* cmd, void* param)
{
   struct mi_root * tmp = NULL;
   if(reload_sources() == 0) {
      tmp = init_mi_tree( 200, MI_OK_S, MI_OK_LEN);
   } else {
      tmp = init_mi_tree( 500, "cannot reload blacklist", 21);
   }

   return tmp;
}


static int mod_init(void)
{
   userblacklist_db_vars();

   if (userblacklist_db_init() != 0) return -1;
   if (init_shmlock() != 0) return -1;
   if (init_source_list() != 0) return -1;
   return 0;
}


static int child_init(int rank)
{
   if (userblacklist_db_open() != 0) return -1;
   dtrie_root=dtrie_init(10);
   if (dtrie_root == NULL) {
      LM_ERR("could not initialize data");
      return -1;
   }
   /* because we've added new sources during the fixup */
   if (reload_sources() != 0) return -1;

   return 0;
}


static int mi_child_init(void)
{
   if (userblacklist_db_open() != 0) return -1;
   dtrie_root=dtrie_init(10);
   if (dtrie_root == NULL) {
      LM_ERR("could not initialize data");
      return -1;
   }
   /* because we've added new sources during the fixup */
   if (reload_sources() != 0) return -1;

   return 0;
}


static void mod_destroy(void)
{
   destroy_source_list();
   destroy_shmlock();
   userblacklist_db_close();
   dtrie_destroy(&dtrie_root, NULL, 10);
}