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-- Gemeinschaft 5 module: cdr event handler class
-- (c) AMOOMA GmbH 2012-2013
--
module(...,package.seeall)
function handler_class()
return Perimeter
end
Perimeter = {}
MALICIOUS_CONTACT_COUNT = 20;
MALICIOUS_CONTACT_TIME_SPAN = 2;
BAN_FUTILE = 2;
function Perimeter.new(self, arg)
arg = arg or {}
object = arg.object or {}
setmetatable(object, self);
self.__index = self;
self.log = arg.log;
self.class = 'cdrsave'
self.database = arg.database;
self.domain = arg.domain;
self.ip_address_table = {}
self:init();
return object;
end
function Perimeter.event_handlers(self)
return { CUSTOM = { ['sofia::pre_register'] = self.sofia_pre_register } }
end
function Perimeter.init(self)
require 'common.configuration_table';
local config = common.configuration_table.get(self.database, 'perimeter');
if config and config.general then
self.malicious_contact_count = tonumber(config.general.malicious_contact_count) or MALICIOUS_CONTACT_COUNT;
self.malicious_contact_time_span = tonumber(config.general.malicious_contact_time_span) or MALICIOUS_CONTACT_TIME_SPAN;
self.ban_futile = tonumber(config.general.ban_futile) or BAN_FUTILE;
self.execute = config.general.execute;
end
self.log:info('[perimeter] PERIMETER - setup perimeter defense - config: ', self.malicious_contact_count, '/', self.malicious_contact_time_span, ', execute: ', self.execute);
end
function Perimeter.sofia_pre_register(self, event)
local ip_address = event:getHeader('network-ip');
self:check_ip(ip_address);
end
function Perimeter.check_ip(self, ip_address)
local event_time = os.time();
if not self.ip_address_table[ip_address] then
self.ip_address_table[ip_address] = { last_contact = event_time, contact_count = 0, start_stamp = event_time, banned = 0 }
end
local ip_record = self.ip_address_table[ip_address];
ip_record.last_contact = event_time;
ip_record.contact_count = ip_record.contact_count + 1;
if ip_record.contact_count > MALICIOUS_CONTACT_COUNT then
if (event_time - ip_record.start_stamp) <= MALICIOUS_CONTACT_TIME_SPAN then
self.log:warning('[', ip_address, '] PERIMETER - too many registration attempts');
ip_record.start_stamp = event_time;
ip_record.contact_count = 0;
if ip_record.banned < BAN_FUTILE then
ip_record.banned = ip_record.banned + 1;
self:ban_ip(ip_address);
else
self.log:error('[', ip_address, '] PERIMETER - ban futile');
end
end
end
end
function Perimeter.ban_ip(self, ip_address)
self.ip_address = ip_address;
if self.execute then
local command = self:expand_variables(self.execute);
self.log:debug('[', ip_address, '] PERIMETER - execute: ', command);
local result = os.execute(command);
if tostring(result) == '0' then
self.log:warning('[', ip_address, '] PERIMETER - IP banned');
end
end
end
function Perimeter.expand_variables(self, line)
return (line:gsub('{([%a%d_-]+)}', function(captured)
return self[captured];
end))
end
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