Copyright © 2007 1&1 Internet AG
db_url (string)db_table (string)id_column (string)carrier_column (string)scan_prefix_column (string)domain_column (string)prob_column (string)rewrite_host_column (string)strip_column (string)comment_column (string)carrier_table (string)rewrite_prefix_column (string)rewrite_suffix_column (string)carrier_id_col (string)carrier_name_col (string)subscriber_table (string)subscriber_user_col (string)subscriber_domain_col (string)subscriber_carrier_col (string)config_source (string)config_file (string)default_tree (string)use_domain (int)fallback_default (int)cr_rewrite_uri (string domain, int hash_source)cr_prime_balance_uri (string domain, int hash_source)cr_rewrite_by_to (string domain, int hash_source)cr_prime_balance_by_to (string domain, int hash_source)cr_prime_balance_by_from (string domain, int hash_source)cr_user_rewrite_uri (string uri, string domain)cr_tree_rewrite_uri (string tree, string domain)cr_reload_routescr_dump_routescr_replace_hostcr_deactivate_hostcr_activate_hostcr_add_hostcr_delete_hostdb_url parameterdb_table parameterid_column parametercarrier_column parameterscan_prefix_column parameterdomain_column parameterprob_column parameterrewrite_host_column parameterstrip_column parametercomment_column parametercarrier_table parameterrewrite_prefix_column parameterrewrite_suffix_column parameterid_col parametercarrier_name_col parametersubscriber_table parametersubscriber_user_col parametersubscriber_domain_col parametersubscriber_carrier_col parameterconfig_source parameterconfig_file parameterdefault_tree parameteruse_domain parameterfallback_default parametercr_replace_host usagecr_deactivate_host usagecr_activate_host usagecr_add_host usagecr_delete_host usageA module which provides routing, balancing and blacklisting capabilities.
The module provides routing, balancing and blacklisting capabilities. It reads routing entries from a database source or from a config file at OpenSER startup. It can uses one routing tree (for one carrier), or if needed for every user a different routing tree (unique for each carrier) for number prefix based routing. It supports several route tree domains, e.g. for failback routes or different routing rules for VoIP and PSTN targets.
Based on the tree, the module decides which number prefixes are forwarded to which gateway. It can also distribute the traffic by ratio parameters. Furthermore, the requests can be distributed by a hash funcion to predictable destinations. The hash source is configurable, two different hash functions are available.
This modules scales up to more than a few million users, and is able to handle more than several hundred thousand routing table entries. It should be able to handle more, but this is not that much tested at the moment. In load balancing scenarios the usage of the config file mode is recommended, to avoid the additional complexity that the database driven routing creates. Please note: although the routing tree is stored in shared memory, for the initial loading from the database on startup private memory is allocated. Thus you'll probably need to increase the private memory pool size. For 40.000 routing rules a "PKG_MEM_POOL_SIZE" of 10 MB is sufficient. This limitation is already fixed in the 1.4.1 release.
Routing tables can be reloaded and edited (in config file mode) with the MI interface, the config file is updated according the changes. This is not implemented for the db interface, because its easier to do the changes directly on the db. But the reload and dump functions works of course here too.
Some module functionality is not fully available in the config file mode, as it is not possible to specify all information that can be stored in the database tables in the config file. Further information about these limitations is given in later sections. For user based routing or LCR you should use the database mode.
Basically this module could be used as an replacement for the lcr and the dispatcher module, if you have certain performance, flexibility and/or integration requirements that these modules don't handle properly. But for small installations it probably make more sense to use the lcr and dispatcher module.
If you want to use this module in failure routes, then you need to call "append_branch()" after rewriting the request URI in order to relay the message to the new target.
The following module must be loaded before this module:
a database module, when a database is used as configuration data source. Only SQL based databases are supported, as this module needs the capability to issue raw queries. Its not possible to use the dbtext or db_berkeley module at the moment.
The following libraries or applications must be installed before running OpenSER with this module loaded:
libconfuse, a configuration file parser library.
db_url (string)Url to the database containing the routing data.
Default value is "mysql://openserro:openserro@localhost/openser".
db_table (string)Name of the table where the routing data is stored.
Default value is "carrierroute".
carrier_column (string)Name of the column containing the carrier id.
Default value is "carrier".
scan_prefix_column (string)Name of column containing the scan prefixes. Scan prexies define the matching portion of a phone number, e.g. we have the scan prefixes 49721 and 49, the called number is 49721913740, it matches 49721, because the longest match is taken. If no prefix matches, the number is not routed. To prevent this, an empty prefix value of NULL could be added.
Default value is "scan_prefix".
domain_column (string)Name of column containing the rule domain. You can define several routing domains to have different routing rules. Maybe you use domain 0 for normal routing and domain 1 if domain 0 failed.
Default value is "domain".
prob_column (string)Name of column containing probability. The probability value is used to distribute the traffic between several gateways. Let's say 70 % of the traffic shall be routed to gateway A, the other 30 % shall be routed to gateway B, we define a rule for gateway A with a prob value of 0.7 and a rule for gateway B with a prob value of 0.3.
If all probabilities for a given prefix, tree and domain don't add to 100%, the prefix values will be adjusted according the given prob values. E.g. if three hosts with prob values of 0.5, 0.5 and 0.4 are defined, the resulting probabilities are 35.714, 35.714 and 28.571%. But its better to choose meaningful values in the first place because of clarity.
Default value is "prob".
rewrite_host_column (string)Name of column containing rewrite host value. An empty field represents a blacklist entry, anything else is put as domain part into the Request URI of the SIP message.
Default value is "rewrite_host".
strip_column (string)Name of the column containing the number of digits to be stripped of the userpart of an URI before prepending rewrite_prefix.
Default value is "strip".
comment_column (string)Name of the column containing an optional comment (useful in large routing tables) The comment is also displayed by the fifo cmd "cr_dump_routes".
Default value is "comment".
carrier_table (string)The name of the table containing the existing carriers, consisting of the ids and corresponding names.
Default value is "route_tree".
rewrite_prefix_column (string)Name of column containing rewrite prefixes. Here you can define a rewrite prefix for the localpart of the SIP URI.
Default value is "rewrite_prefix".
rewrite_suffix_column (string)Name of column containing rewrite suffixes. Here you can define a rewrite suffix for the localpart of the SIP URI.
Default value is "rewrite_suffix".
carrier_id_col (string)The name of the column in the carrier table containing the carrier id.
Default value is "id".
carrier_name_col (string)The name of the column in the carrier table containing the carrier name.
Default value is "carrier".
subscriber_table (string)The name of the table containing the subscribers
Default value is "subscriber".
subscriber_user_col (string)The name of the column in the subscriber table containing the usernames.
Default value is "username".
subscriber_domain_col (string)The name of the column in the subscriber table containing the domain of the subscriber.
Default value is "domain".
subscriber_carrier_col (string)The name of the column in the subscriber table containing the carrier id of the subscriber.
Default value is "cr_preferred_carrier".
config_source (string)Specifies whether the module loads its config data from a file or from a database. Possible values are file or db.
Default value is "file".
config_file (string)Specifies the path to the config file.
Default value is "/etc/openser/carrierroute.conf".
default_tree (string)The name of the carrier tree used per default (if the current subscriber has no preferred tree)
Default value is "default".
use_domain (int)When using tree lookup per user, this parameter specifies whether to use the domain part for user matching or not.
Default value is "0".
fallback_default (int)This parameter defines the behaviour when using user-based tree lookup. If the user has a non-existing tree set and fallback_default is set to 1, the default tree is used. Otherwise, cr_user_rewrite_uri returns an error.
Default value is "1".
All functions needs a string value to specify a certain tree domain or tree. Its further necessary to specify source of the hashing algorithm. If this parameter is ommited like in the cr_user_rewrite_uri and cr_tree_rewrite_uri functions, a default hash source, the call id, is choosen.
cr_rewrite_uri (string domain, int hash_source)This function searches for the longest match for the Request URI at the given domain in the default tree and rewrites the Request URI. Returns -1 if there is no data found or an empty rewrite host on the longest match is found. This function is only usable with requests that contains a valid numerical request URI, e.g. INVITEs.
Meaning of the parameters is as follows:
domain - Name of the routing domain to be used.
hash_source - The hash values of the destination set must be a contiguous range starting at 1, limited by the configuration parameter max_targets. Possible values for hash_source are: call_id, from_uri, from_user, to_uri and to_user.
cr_prime_balance_uri (string domain, int hash_source)Balances the request URI to the desination set given by domain in the default tree. The hash_source defines the parameter which is passed to the hash function. Return codes are the same as for cr_rewrite_uri. This function is only usable with requests that contains a valid numerical request URI, e.g. INVITEs.
It uses the prime hash algorithm to calculate the hash values. This means that the fuction behaves different then the normal routing function. If you don't know what this prime functionality is, you should just use the cr_rewrite_uri function. The prime routing algorithm not use the configured probabilities in order to route requests, it just uses a fixed hash distribution. If one of the hash targets is not available, and no backup rule is configured, the function will return -1.
Meaning of the parameters is as follows:
domain - Name of the routing domain to be used.
hash_source - The hash values of the destination set must be a contiguous range starting at 1, limited by the configuration parameter max_targets. Possible values for hash_source are: from_user and to_user.
cr_rewrite_by_to (string domain, int hash_source)Like cr_rewrite_uri, except that the to URI is used for prefix matching instead the request URI. Return codes are the same as for cr_rewrite_uri. This function is usable on requests that don't contain a valid request URI, like REGISTERs.
Meaning of the parameters is as follows:
domain - Name of the routing domain to be used.
hash_source - The hash values of the destination set must be a contiguous range starting at 1, limited by the configuration parameter max_targets. Possible values for hash_source are: call_id, from_uri, from_user, to_uri and to_user.
cr_prime_balance_by_to (string domain, int hash_source)Like cr_prime_balance_uri, except that the to URI is used for prefix matching instead the request URI. Return codes are the same as for cr_rewrite_uri. This function is usable on requests that don't contain a valid request URI, like REGISTERs.
Meaning of the parameters is as follows:
domain - Name of the routing domain to be used.
hash_source - The hash values of the destination set must be a contiguous range starting at 1, limited by the configuration parameter max_targets. Possible values for hash_source are: from_user and to_user.
cr_prime_balance_by_from (string domain, int hash_source)Like cr_prime_balance_uri, except that the from URI is used for prefix matching instead the request URI. Return codes are the same as for cr_rewrite_uri. This function is usable on requests that don't contain a valid request URI, like REGISTERs.
Meaning of the parameters is as follows:
domain - Name of the routing domain to be used.
hash_source - The hash values of the destination set must be a contiguous range starting at 1, limited by the configuration parameter max_targets. Possible values for hash_source are: from_user and to_user.
cr_user_rewrite_uri (string uri, string domain)Rewrites the request URI, the given URI is used to determine the carrier tree to be used. The carrier is derived from a database entry belonging to the user part of the URI. The domain identifies the routing domain inside the carrier tree. This function cannot be used in the config file mode, as it needs a mapping of the given user to a certain carrier.
Meaning of the parameters is as follows:
uri - Name of the user for the carrier tree lookup. Additional to a string variable any pseudo-variable could be used as input.
domain - Name of the routing domain to be used.
cr_tree_rewrite_uri (string tree, string domain)Rewrites the request URI, using the carrier tree specified by the tree parameter with the given domain. The call id is used as hash source.
Meaning of the parameters is as follows:
tree - The routing tree to be used. Additional to a string variable any pseudo-variable could be used as input.
domain - Name of the routing domain to be used.
All commands understand the "-?" parameter to print a short help message. The options have to be quoted as one string to be passed to MI interface. Each option except host and new host can be wildcarded by * (but only * and not things like "-d prox*").
cr_reload_routesThis command reloads the routing data from the data source.
Important: When new domains have been added, a restart of the server must be done, because the mapping of the ids used in the config script cannot be updated at runtime at the moment. So a reload could result in a wrong routing behaviour, because the ids used in the script could differ from the one used internally from the server. Modifying of already existing domains is no problem. Also when changing carrier mapping, a restart of the server is required.
cr_replace_hostThis command can replace the rewrite_host of a route rule, it is only usable in file mode. Following options are possible:
-d - the domain containing the host
-p - the prefix containing the host
-h - the host to be replaced
-t - the new host
Use the "null" prefix to specify an empty prefix.
cr_deactivate_hostThis command deactivates the specified host, i.e. it sets its status to 0. It is only usable in file mode. Following options are possible:
-d - the domain containing the host
-p - the prefix containing the host
-h - the host to be deactivated
-t - the new host used as backup
When -t (new_host) is specified, the portion of traffic for the deactivated host is routed to the host given by -t. This is indicated in the output of dump_routes. The backup route is deactivated if the host is activated again.
Use the "null" prefix to specify an empty prefix.
cr_activate_hostThis command activates the specified host, i.e. it sets its status to 1. It is only usable in file mode. Following options are possible:
-d - the domain containing the host
-p - the prefix containing the host
-h - the host to be activated
Use the "null" prefix to specify an empty prefix.
cr_add_hostThis command adds a route rule, it is only usable in file mode. Following options are possible:
-d - the domain containing the host
-p - the prefix containing the host
-h - the host to be added
-w - the weight of the rule
-P - an optional rewrite prefix
-S - an optional rewrite suffix
-i - an optional hash index
-s - an optional strip value
Use the "null" prefix to specify an empty prefix.
cr_delete_hostThis command delete the specified hosts or rules, i.e. remove them from the route tree. It is only usable in file mode. Following options are possible:
-d - the domain containing the host
-p - the prefix containing the host
-h - the host to be added
-w - the weight of the rule
-P - an optional rewrite prefix
-S - an optional rewrite suffix
-i - an optional hash index
-s - an optional strip value
Use the "null" prefix to specify an empty prefix.
Example 1-30. Configuration example - OpenSER script
...
route {
# do something with the message, for example..
if (loose_route()) { t_relay(); return; };
# do more stuff..
# route calls based on hash over callid
# choose route domain 0 of the default carrier
if(!cr_rewrite_uri("0", "call_id")){
sl_send_reply("403", "Not allowed");
} else {
# In case of failure, re-route the request
t_on_failure("1");
# Relay the request to the gateway
t_relay();
}
}
failure_route[1] {
# In case of failure, send it to an alternative route:
if (t_check_status("408|5[0-9][0-9]")) {
#choose route domain 1 of the default carrier
if(!cr_rewrite_uri("1", "call_id")){
t_reply("403", "Not allowed");
} else {
t_on_failure("2");
t_relay();
}
}
}
failure_route[2] {
# further processing
}
...
Example 1-31. Configuration example - module configuration
The following config file specifies within the default carrier two domains, each with an prefix that contains two hosts. It is not possible to specify another carrier if you use the config file as data source.
All traffic will be equally distributed between the hosts, both are active. The hash algorithm will working over the [1,2] set, messages hashed to one will go to the first host, the other to the second one. Don't use a hash index value of zero. If you ommit the hash completly, the module gives them a autogenerated value, starting from one.
Use the "null" prefix to specify an empty prefix in the config file. Please note that the prefix is matched against the request URI (or to URI), if they did not contain a valid numerical URI, no match is possible. So for loadbalancing purposes e.g. for your registrars, you should use an empty prefix.
...
domain proxy {
prefix 49 {
max_targets = 2
target proxy1.localdomain {
prob = 0.500000
hash_index = 1
status = 1
comment = "test target 1"
}
target proxy2.localdomain {
prob = 0.500000
hash_index = 2
status = 1
comment = "test target 2"
}
}
}
domain register {
prefix NULL {
max_targets = 2
target register1.localdomain {
prob = 0.500000
hash_index = 1
status = 1
comment = "test target 1"
}
target register2.localdomain {
prob = 0.500000
hash_index = 2
status = 1
comment = "test target 2"
}
}
}
...
Before running OpenSER with carrierroute, you have to setup the database table where the module will store the routing data. For that, if the table was not created by the installation script or you choose to install everything by yourself you can use the carrierroute-create.sql SQL script in the database directories in the openser/scripts folder as template. Database and table name can be set with module parameters so they can be changed, but the name of the columns must be as they are in the SQL script. You can also find the complete database documentation on the project webpage, http://www.openser-project.org/docs/db-tables/openser-db-devel.html.
For a minimal configuration either use the config file given above, or insert some data into the tables of the module.
Example 1-32. Example database content - carrierroute table
... +----+---------+-------------+--------+------+-------+---------------+ | id | carrier | scan_prefix | domain | prob | strip | rewrite_host | +----+---------+-------------+--------+------+-------+---------------+ | 1 | 1 | 49 | 0 | 0.5 | 0 | de-1.carrier1 | | 2 | 1 | 49 | 0 | 0.5 | 0 | de-2.carrier1 | | 3 | 1 | | 0 | 1 | 0 | gw.carrier1 | | 5 | 1 | 49 | 1 | 1 | 0 | gw.carrier1 | | 6 | 2 | 49 | 0 | 0.5 | 0 | de-1.carrier2 | | 7 | 2 | 49 | 0 | 0.5 | 0 | de-2.carrier2 | | 8 | 2 | | 0 | 1 | 0 | gw.carrier2 | | 9 | 2 | 49 | 1 | 1 | 0 | gw.carrier2 | | 10 | 3 | 49 | 0 | 1 | 0 | de-gw.default | | 11 | 3 | | 0 | 1 | 0 | gw.default | +----+---------+-------------+--------+------+-------+---------------+ ...
This table contains two routes to two gateways for the "49" prefix, and a default route for other prefixes over carrier 2 and carrier 1. The gateways for the default carrier will be used for functions that don't support the user specific carrier lookup. The routing rules for carrier 1 and carrier 2 for the "49" prefix contains a additional rule with the domain 1, that can be used for example as fallback if the gateways in domain 0 are not reachable.
Example 1-33. Example database content - route_tree table
... +----+----------+ | id | carrier | +----+----------+ | 1 | carrier1 | | 2 | carrier2 | | 3 | default | +----+----------+ ...
This table contains the mapping of the carrier id to actual names.
For a functional routing with the "cr_user_rewrite_uri" function the "cr_preferred_carrier" column must be added to the subscriber table (or to the table and column that you specified as modul parameter) to choose the actual carrier for the users.
Take a look at http://www.openser-project.org/.
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