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kamailio/modules/lcr/README

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LCR (Least Cost Routing) Module
Juha Heinanen
<jh@tutpro.com>
Edited by
Juha Heinanen
<jh@tutpro.com>
Copyright © 2005-2010 Juha Heinanen
__________________________________________________________________
Table of Contents
1. Admin Guide
1. Overview
2. Dependencies
2.1. SIP Router modules
2.2. External libraries or applications
3. Parameters
3.1. db_url (string)
3.2. lcr_gw_table (string)
3.3. id_column (string)
3.4. lcr_id_column (string)
3.5. gw_name_column (string)
3.6. ip_addr_column (string)
3.7. hostname_column (string)
3.8. port_column (string)
3.9. params_column (string)
3.10. uri_scheme_column (string)
3.11. transport_column (string)
3.12. strip_column (string)
3.13. tag_column (string)
3.14. flags_column (string)
3.15. defunct_column (string)
3.16. lcr_rule_table (string)
3.17. prefix_column (string)
3.18. from_uri_column (string)
3.19. request_uri_column (string)
3.20. stopper_column (string)
3.21. enabled_column (string)
3.22. lcr_rule_target_table (string)
3.23. rule_id_column (string)
3.24. gw_id_column (string)
3.25. priority_column (string)
3.26. weight_column (string)
3.27. lcr_count (integer)
3.28. gw_uri_avp (AVP string)
3.29. ruri_user_avp (AVP string)
3.30. tag_avp (AVP string)
3.31. flags_avp (AVP string)
3.32. defunct_capability (integer)
3.33. lcr_id_avp (AVP string)
3.34. defunct_gw_avp (AVP string)
3.35. lcr_rule_hash_size (integer)
3.36. lcr_gw_count (integer)
3.37. dont_strip_or_tag_flag (integer)
3.38. fetch_rows (integer)
4. Functions
4.1. load_gws(lcr_id[, uri_user[, caller_uri]])
4.2. next_gw()
4.3. defunct_gw(period)
4.4. from_gw(lcr_id[, ip_addr, proto])
4.5. from_any_gw([ip_addr, proto])
4.6. to_gw(lcr_id[, ip_addr, proto])
4.7. to_any_gw([ip_addr, proto])
5. Exported RPC Commands
5.1. lcr.reload
5.2. lcr.dump_gws
5.3. lcr.dump_rules
5.4. lcr.defunct_gw
6. Known Limitations
List of Examples
1.1. Setting db_url module parameter
1.2. Setting gw_table module parameter
1.3. Setting id_column module parameter
1.4. Setting lcr_id_column module parameter
1.5. Setting gw_name_column module parameter
1.6. Setting ip_addr_column module parameter
1.7. Setting hostname_column module parameter
1.8. Setting port_column module parameter
1.9. Setting params_column module parameter
1.10. Setting uri_scheme_column module parameter
1.11. Setting transport_column module parameter
1.12. Setting strip_column module parameter
1.13. Setting tag_column module parameter
1.14. Setting flags_column module parameter
1.15. Setting defunct_column module parameter
1.16. Setting lcr_rule_table module parameter
1.17. Setting prefix_column module parameter
1.18. Setting from_uri_column module parameter
1.19. Setting request_uri_column module parameter
1.20. Setting stopper_column module parameter
1.21. Setting enabled_column module parameter
1.22. Setting lcr_rule_target_table module parameter
1.23. Setting rule_id_column module parameter
1.24. Setting gw_id_column module parameter
1.25. Setting priority_column module parameter
1.26. Setting weight_column module parameter
1.27. Setting lcr_count module parameter
1.28. Setting gw_uri_avp module parameter
1.29. Setting ruri_user_avp module parameter
1.30. Setting tag_avp module parameter
1.31. Setting flags_avp module parameter
1.32. Setting defunct_capability module parameter
1.33. Setting lcr_id_avp module parameter
1.34. Setting defunct_gw_avp module parameter
1.35. Setting lcr_rule_hash_size module parameter
1.36. Setting lcr_gw_count module parameter
1.37. Setting dont_strip_or_tag_flag module parameter
1.38. Set fetch_rows parameter
1.39. load_gws usage
1.40. next_gw usage from a route block
1.41. next_gw usage from a failure route block
1.42. defunct_gw usage
1.43. from_gw usage
1.44. from_gw usage
1.45. to_gw usage
1.46. to_gw usage
1.47. lcr.reload RPC example
1.48. lcr.dump_gws RPC example
1.49. lcr.dump_rules RPC example
1.50. lcr.defunct_gw RPC example
Chapter 1. Admin Guide
Table of Contents
1. Overview
2. Dependencies
2.1. SIP Router modules
2.2. External libraries or applications
3. Parameters
3.1. db_url (string)
3.2. lcr_gw_table (string)
3.3. id_column (string)
3.4. lcr_id_column (string)
3.5. gw_name_column (string)
3.6. ip_addr_column (string)
3.7. hostname_column (string)
3.8. port_column (string)
3.9. params_column (string)
3.10. uri_scheme_column (string)
3.11. transport_column (string)
3.12. strip_column (string)
3.13. tag_column (string)
3.14. flags_column (string)
3.15. defunct_column (string)
3.16. lcr_rule_table (string)
3.17. prefix_column (string)
3.18. from_uri_column (string)
3.19. request_uri_column (string)
3.20. stopper_column (string)
3.21. enabled_column (string)
3.22. lcr_rule_target_table (string)
3.23. rule_id_column (string)
3.24. gw_id_column (string)
3.25. priority_column (string)
3.26. weight_column (string)
3.27. lcr_count (integer)
3.28. gw_uri_avp (AVP string)
3.29. ruri_user_avp (AVP string)
3.30. tag_avp (AVP string)
3.31. flags_avp (AVP string)
3.32. defunct_capability (integer)
3.33. lcr_id_avp (AVP string)
3.34. defunct_gw_avp (AVP string)
3.35. lcr_rule_hash_size (integer)
3.36. lcr_gw_count (integer)
3.37. dont_strip_or_tag_flag (integer)
3.38. fetch_rows (integer)
4. Functions
4.1. load_gws(lcr_id[, uri_user[, caller_uri]])
4.2. next_gw()
4.3. defunct_gw(period)
4.4. from_gw(lcr_id[, ip_addr, proto])
4.5. from_any_gw([ip_addr, proto])
4.6. to_gw(lcr_id[, ip_addr, proto])
4.7. to_any_gw([ip_addr, proto])
5. Exported RPC Commands
5.1. lcr.reload
5.2. lcr.dump_gws
5.3. lcr.dump_rules
5.4. lcr.defunct_gw
6. Known Limitations
1. Overview
The Least Cost Routing (LCR) module implements capability to serially
forward a request to one or more gateways so that the order in which
the gateways is tried is based on admin defined "least cost" rules.
The LCR module supports many independent LCR instances (gateways and
least cost rules). Each such instance has its own LCR instance
identifier. Identifiers of normal LCR instances are positive integers.
Gateways may belong to special LCR instance with identifier 0 meaning
that such gateways belong to all normal LCR instances.
For the purpose of facilitating least cost routing of requests, each
gateway of an LCR instance is associated with one or more <prefix, from
uri pattern, request uri pattern, priority, weight> tuples. A gateway
matches a request if user part of the Request-URI matches a "prefix",
the caller's URI matches a "From-URI" pattern and the callee's URI
matches a "Request-URI" pattern in a tuple that is associated with the
gateway.
When the function load_gws() is called, matching gateways (that are not
currently designated as defunct) are ordered for forwarding purposes as
follows:
* (1) according to longest Request-URI user part match
* (2) according to tuple's priority
* (3) according to tuple's randomized weight
A tuple can be marked as a "stopper" tuple. If a "stopper" tuple
matches, then matching stops at it and all other tuples with shorter
prefixes are not considered.
Prefix is a string of characters or NULL. From-URI pattern and
Request-URI pattern are regular expressions (see 'man pcresyntax' for
syntax), an empty string, or NULL. An empty or NULL From-URI pattern,
Request-URI pattern or prefix matches anything. Smaller priority value
means higher priority (highest priority value being 0 and lowest being
255).
Weight is an integer value from 1 to 254. Weight implementation is
fast, but unfair favoring larger weight values at the expense smaller
ones. For example, if two gateways have weights 1 and 2, probability
that the gateway with weight 1 is tried first is 1/4, not 1/3. Two
scripts are provided in lcr/utils directory that can be used to check
the probabilities resulting from a given set of weight values. Same can
be done with command 'kamctl eval_weights'.
The function next_gw() can then be used to select one gateway at a time
for forwarding. Upon each call, unless "dont_strip_or_tag_flag" flag is
set, user part of the original Request-URI is first stripped by the
number of characters as specified by the gateway's strip count and then
prefixed by the gateway's prefix. Upon each call, if a gateway's
hostname is NULL, Request-URI will be rewritten based on gateway's URI
scheme, IP address, port, parameters, and transport protocol. If
hostname is not NULL and IP address is NULL, Request-URI will be
rewritten based on the gateway's URI scheme, hostname, port, parameters
and transport protocol. If both hostname and IP address are not NULL,
Request-URI will be rewritten based on gateway's URI scheme, hostname,
and parameters, and destination URI is set based on gateway's URI
scheme, IP address, port, and transport protocol.
Valid URI scheme values are NULL = sip, 1 = sip and 2 = sips. Currently
valid transport protocol values are NULL and 0 = none, 1 = udp, 2 =
tcp, 3 = tls, and 4 = sctp.
As a side effect of gateway selection, selected gateway's tag and flags
(that may contain information about the gateway and its capabilities)
are stored to tag_avp and flags_avp, respectively, if the corresponding
module parameter has been defined.
2. Dependencies
2.1. SIP Router modules
2.2. External libraries or applications
2.1. SIP Router modules
The following modules must be loaded before this module:
* A database module like mysql, postgres or dbtext.
2.2. External libraries or applications
The following libraries or applications must be installed before
running SIP Router with this module:
* libpcre
3. Parameters
3.1. db_url (string)
3.2. lcr_gw_table (string)
3.3. id_column (string)
3.4. lcr_id_column (string)
3.5. gw_name_column (string)
3.6. ip_addr_column (string)
3.7. hostname_column (string)
3.8. port_column (string)
3.9. params_column (string)
3.10. uri_scheme_column (string)
3.11. transport_column (string)
3.12. strip_column (string)
3.13. tag_column (string)
3.14. flags_column (string)
3.15. defunct_column (string)
3.16. lcr_rule_table (string)
3.17. prefix_column (string)
3.18. from_uri_column (string)
3.19. request_uri_column (string)
3.20. stopper_column (string)
3.21. enabled_column (string)
3.22. lcr_rule_target_table (string)
3.23. rule_id_column (string)
3.24. gw_id_column (string)
3.25. priority_column (string)
3.26. weight_column (string)
3.27. lcr_count (integer)
3.28. gw_uri_avp (AVP string)
3.29. ruri_user_avp (AVP string)
3.30. tag_avp (AVP string)
3.31. flags_avp (AVP string)
3.32. defunct_capability (integer)
3.33. lcr_id_avp (AVP string)
3.34. defunct_gw_avp (AVP string)
3.35. lcr_rule_hash_size (integer)
3.36. lcr_gw_count (integer)
3.37. dont_strip_or_tag_flag (integer)
3.38. fetch_rows (integer)
3.1. db_url (string)
URL of the database table to be used.
Default value is "mysql://kamailioro:kamailioro@localhost/kamailio".
Example 1.1. Setting db_url module parameter
...
modparam("lcr","db_url","dbdriver://username:password@dbhost/dbname")
...
3.2. lcr_gw_table (string)
Name of the table holding gateways definitions.
Default value is "lcr_gw".
Example 1.2. Setting gw_table module parameter
...
modparam("lcr", "lcr_gw_table","gw")
...
3.3. id_column (string)
Name of the auto-increment, primary key column. Common to all lcr
module tables.
Default value is "id".
Example 1.3. Setting id_column module parameter
...
modparam("lcr", "id_column", "row_id")
...
3.4. lcr_id_column (string)
Name of the column holding the identifier of an LCR instance. Common to
all lcr module tables. In lcr_rule and lcr_rule_target tables, value of
the column is integer from 1 to lcr_count. In lcr_gw table, value of
the column is from 0 to lcr_count.
Default value is "lcr_id".
Example 1.4. Setting lcr_id_column module parameter
...
modparam("lcr", "lcr_id_column", "lcr_identifier")
...
3.5. gw_name_column (string)
Name of the column holding gateway's name for documentation purpose.
Default value is "gw_name".
Example 1.5. Setting gw_name_column module parameter
...
modparam("lcr", "gw_name_column", "name")
...
3.6. ip_addr_column (string)
Name of the column holding the IPv4 or IPv6 address of the gateway.
Default value is "ip_addr".
Example 1.6. Setting ip_addr_column module parameter
...
modparam("lcr", "ip_addr_column", "ip")
...
3.7. hostname_column (string)
Name of the column holding gateway's hostname that is used in
Request-URI hostpart, when request is sent to the gateway.
Default value is "hostname".
Example 1.7. Setting hostname_column module parameter
...
modparam("lcr", "hostname_column", "host")
...
3.8. port_column (string)
Name of the column holding the port number of the gateway.
Default value is "port".
Example 1.8. Setting port_column module parameter
...
modparam("lcr", "port_column", "port")
...
3.9. params_column (string)
Name of the column holding gateway's parameters that is used in
Request-URI, when request is sent to the gateway.
Default value is "params".
Example 1.9. Setting params_column module parameter
...
modparam("lcr", "params_column", "parameters")
...
3.10. uri_scheme_column (string)
Name of the column holding the uri scheme of the gateway.
Default value is "uri_scheme".
Example 1.10. Setting uri_scheme_column module parameter
...
modparam("lcr", "uri_scheme_column", "uri_scheme")
...
3.11. transport_column (string)
Name of the column holding the transport protocol to be used for the
gateway.
Default value is "transport".
Example 1.11. Setting transport_column module parameter
...
modparam("lcr", "transport_column", "trans")
...
3.12. strip_column (string)
Name of the column holding the number of characters to be stripped from
the front of Request-URI user part before inserting tag.
Default value is "strip".
Example 1.12. Setting strip_column module parameter
...
modparam("lcr", "strip_column", "strip_count")
...
3.13. tag_column (string)
Name of the column holding gateway specific tag string that is added to
Request URI userpart after stripping.
Default value is "tag".
Example 1.13. Setting tag_column module parameter
...
modparam("lcr", "tag_column", "gw_tag")
...
3.14. flags_column (string)
Name of the column holding gateway specific flag values.
Default value is "flags".
Example 1.14. Setting flags_column module parameter
...
modparam("lcr", "flags_column", "gw_flags")
...
3.15. defunct_column (string)
Name of the column holding UNIX timestamp telling the time until which
the gw is considered as defunct. If timestamp value is 4294967295 (=
max UNIX timestamp value) or greater, gw is considered currently unused
and is not loaded into memory at all.
Default value is "defunct".
Example 1.15. Setting defunct_column module parameter
...
modparam("lcr", "defunct_column", "defunct_until")
...
3.16. lcr_rule_table (string)
Name of the table holding the LCR rules.
Default value is "lcr_rule".
Example 1.16. Setting lcr_rule_table module parameter
...
modparam("lcr", "lcr_rule_table", "rules")
...
3.17. prefix_column (string)
Name of the column holding prefix of Request-URI user part and prefix
of gateway.
Default value is "prefix".
Example 1.17. Setting prefix_column module parameter
...
modparam("lcr", "prefix_column", "number_prefix")
...
3.18. from_uri_column (string)
Name of the column holding the From (caller's) URI.
Default value is "from_uri".
Example 1.18. Setting from_uri_column module parameter
...
modparam("lcr", "from_uri_column", "caller_uri")
...
3.19. request_uri_column (string)
Name of the column holding the regular expression to match against the
complete request URI (including the "sip:" prefix).
Default value is "request_uri".
Example 1.19. Setting request_uri_column module parameter
...
modparam("lcr", "request_uri_column", "callee_uri")
...
3.20. stopper_column (string)
Name of the column holding rule's stopper attribute.
Default value is "stopper".
Example 1.20. Setting stopper_column module parameter
...
modparam("lcr", "stopper_column", "stop")
...
3.21. enabled_column (string)
Name of the column telling is the rule is currently enabled or
disabled.
Default value is "enabled".
Example 1.21. Setting enabled_column module parameter
...
modparam("lcr", "enabled_column", "in_use")
...
3.22. lcr_rule_target_table (string)
Name of the table holding information about the LCR rule targets
(gateways).
Default value is "lcr_rule_target".
Example 1.22. Setting lcr_rule_target_table module parameter
...
modparam("lcr", "lcr_rule_target_table", "rules")
...
3.23. rule_id_column (string)
Name of lcr_rule_target_table column containing an id of lcr_rule
table.
Default value is "rule_id".
Example 1.23. Setting rule_id_column module parameter
...
modparam("lcr", "rule_id_column", "rule")
...
3.24. gw_id_column (string)
Name of lcr_rule_target_table column containing an id of lcr_gw table.
Default value is "gw_id".
Example 1.24. Setting gw_id_column module parameter
...
modparam("lcr", "gw_id_column", "gw")
...
3.25. priority_column (string)
Name of the column holding the priority of the rule target.
Default value is "priority".
Example 1.25. Setting priority_column module parameter
...
modparam("lcr", "priority_column", "priority")
...
3.26. weight_column (string)
Name of the column holding weight of rule target.
Default value is "weight".
Example 1.26. Setting weight_column module parameter
...
modparam("lcr","weight_column", "target_weight")
...
3.27. lcr_count (integer)
Maximun value of lcr_id.
Default value is 1.
Example 1.27. Setting lcr_count module parameter
...
modparam("lcr", "lcr_count", 10)
...
3.28. gw_uri_avp (AVP string)
Internal AVP that load_gws() function uses to store information of
matching gateways.
There is NO default value, thus this variable must be defined in
sip-router.cfg.
Example 1.28. Setting gw_uri_avp module parameter
...
modparam("lcr", "gw_uri_avp", "$avp(i:709)")
...
3.29. ruri_user_avp (AVP string)
Internal AVP that next_gw function uses to store Request-URI user for
subsequent next_gw calls.
There is NO default value, thus this variable must be defined in
sip-router.cfg.
Example 1.29. Setting ruri_user_avp module parameter
...
modparam("lcr", "ruri_user_avp", "$avp(i:500)")
...
3.30. tag_avp (AVP string)
If defined, an AVP where successful next_gw and from_gw functions store
gateway's tag.
There is NO default value, i.e, if not defined, gateway's tag is not
stored anywhere.
Example 1.30. Setting tag_avp module parameter
...
modparam("lcr", "tag_avp", "$avp(lcr_tag)")
...
3.31. flags_avp (AVP string)
If defined, an AVP where successful next_gw and from_gw functions store
gateway's flags.
There is NO default value, i.e, if not defined, gateway's flags are not
stored anywhere.
Example 1.31. Setting flags_avp module parameter
...
modparam("lcr", "flags_avp", "$avp(i:712)")
...
3.32. defunct_capability (integer)
Tells if defunct capability of (non-responsive) gateways is supported.
Non-zero value turns on defunct capability.
Default value is 0.
Example 1.32. Setting defunct_capability module parameter
...
modparam("lcr", "defunct_capability", 1)
...
3.33. lcr_id_avp (AVP string)
Internal AVP that load_gws() function uses to store LCR instance
identifier of loaded gateways. Only needed if gateway defunct
capability has been activated.
There is NO default value.
Example 1.33. Setting lcr_id_avp module parameter
...
modparam("lcr", "lcr_id_avp", "$avp(s:lcr_id_avp)")
...
3.34. defunct_gw_avp (AVP string)
Internal AVP that next_gw() function uses to store internal index of
the selected gateway for later use by defunct_gw() function. Only
needed if gateway defunct capability has been activated.
There is NO default value.
Example 1.34. Setting defunct_gw_avp module parameter
...
modparam("lcr", "defunct_gw_avp", "$avp(s:defunct_gw_avp)")
...
3.35. lcr_rule_hash_size (integer)
Defines the size of hash table used to store LCR rules. Hashing is done
based on rule's prefix. Larger value means less collisions with other
prefixes. Hash size value should be a power of 2.
Default value is 128.
Example 1.35. Setting lcr_rule_hash_size module parameter
...
modparam("lcr", "lcr_rule_hash_size", 1024)
...
3.36. lcr_gw_count (integer)
Defines the maximum number of gateways in lcr_gw table.
Default value is 128.
Example 1.36. Setting lcr_gw_count module parameter
...
modparam("lcr", "lcr_gw_count", 1024)
...
3.37. dont_strip_or_tag_flag (integer)
Defines the flag number used to tell if stripping and tagging is done
for the selected gateway.
Default value is -1 meaning that the flag is not defined.
Example 1.37. Setting dont_strip_or_tag_flag module parameter
...
modparam("lcr", "dont_strip_or_tag_flag", 10)
...
3.38. fetch_rows (integer)
The number of the rows to be fetched at once from database when loading
data from lcr_rule table. This value can be used to tune the load time
at startup. For 1MB of private memory (default) it should be below
3750. In order for this parameter to have effect, the database driver
must support fetch_result() capability.
Default value is "1024".
Example 1.38. Set fetch_rows parameter
...
modparam("lcr", "fetch_rows", 3000)
...
4. Functions
4.1. load_gws(lcr_id[, uri_user[, caller_uri]])
4.2. next_gw()
4.3. defunct_gw(period)
4.4. from_gw(lcr_id[, ip_addr, proto])
4.5. from_any_gw([ip_addr, proto])
4.6. to_gw(lcr_id[, ip_addr, proto])
4.7. to_any_gw([ip_addr, proto])
4.1. load_gws(lcr_id[, uri_user[, caller_uri]])
Loads attributes of matching gateways to gw_uri_avp (see Overview
section). Argument lcr_id specifies the used LCR instance. It can be a
positive integer or a pseudo variable containing an integer value. If
uri_user is given, it is used, instead of Request-URI user part, to
look for matching gateways. Caller's URI may be given by caller_uri
argument. If caller_uri argument is omitted, it defaults to empty
string. Both uri_user and caller_uri argument may be a string or a
pseudo variable containing a sting value.
Returns 1 if at least one matching gateway was found, 2 if no matching
gateways was found, and -1 on error.
Execution time of load_gws() function is O(N) * O(M), where N is number
of different prefix lengths and M is number of collisions for matching
prefix(es) in lcr rules hash table of the LCR instance.
This function can be used from REQUEST_ROUTE.
Example 1.39. load_gws usage
...
if (!load_gws(1, $rU, $var(caller_uri))) {
sl_send_reply("500", "Server Internal Error - Cannot load gateways");
exit;
};
...
4.2. next_gw()
Upon first call, fetches attribute values stored in first gw_uri_avp,
destroys that AVP, and rewrites Request-URI and possibly also
destination URI as described in the Overview section. Saves user part
of Request-URI into ruri_user_avp for use in subsequent next_gw()
calls.
Upon subsequent calls, does the same as in above, but takes user part
of Request-URI from ruri_user_avp.
As a side effect, stores gateway's tag and flags to tag_avp and
flags_avp, respectively, if the corresponding module parameter has been
defined.
Returns 1 on success and -1 if there were no gateways left or if an
error occurred (see syslog).
Must be preceded by successful load_gws() call.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
Example 1.40. next_gw usage from a route block
...
if (!next_gw()) {
sl_send_reply("503", "Service not available - No gateways");
exit;
};
...
Example 1.41. next_gw usage from a failure route block
...
if (!next_gw()) {
t_reply("503", "Service not available - No more gateways");
exit;
};
...
4.3. defunct_gw(period)
Defuncts gateway denoted by lcr_id_avp and defunct_gw_avp (which were
set by previuos next_gw() call) for a period of seconds given as
argument. Argument must be a positive integer constant or a pseudo
variable with positive integer value. Value of defunct column in
database is not updated.
Returns 1 on success and -1 in case of error (see syslog).
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
Example 1.42. defunct_gw usage
...
defunct_gw(60);
...
4.4. from_gw(lcr_id[, ip_addr, proto])
Checks if request comes from IP address and transport protocol
specified for a gateway in LCR instance lcr_id. Fails if the LCR
instance includes one or more gateways without IP address. IP address
and transport protocol to be checked are either taken from source IP
address of the request or (if present) from ip_addr and proto
arguments.
lcr_id can be an integer constant or a pseudo variable holding an
integer value. ip_addr can be a string or a pseudo variable holding a
string value. proto can be an integer constant (0 = ANY, 1 = UDP, 2 =
TCP, 3 = TLS, 4 = SCTP) or a pseudo variable holding such an integer
value.
If request comes from a gateway, gateway's tag and flags are stored as
a side effect to tag_avp and flags_avp, respectively, if the
corresponding module parameter has been defined.
Returns 1 on success and -1 on failure or on error.
Execution time of from_gw() function is O(log N), where N is number of
gateways in the LCR instance.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
ONREPLY_ROUTE.
Example 1.43. from_gw usage
...
if (from_gw(1, $avp(s:real_source_addr), 2) {
...
};
...
4.5. from_any_gw([ip_addr, proto])
Checks if request comes from IP address and transport protocol
specified for any gateway. Only LCR instances, where all gateways have
IP address, are included in the test. IP address and transport protocol
to be checked are either taken from source IP address and transport
protocol of the request or (if present) from ip_addr and proto
arguments. See from_gw() function for more info about the arguments.
If any gateway has the IP address and transport protocol, function
returns LCR identifier of the gateway. Returns -1 on error or if the
request does not come from a gateway.
If request comes from a gateway, gateway's tag and flags are stored as
a side effect to tag_avp and flags_avp, respectively, if the
corresponding module parameter has been defined.
Execution time of from_gw() function is M * O(log N), where M is number
of LCR instances and N is average number of gateways in LCR instances.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
ONREPLY_ROUTE.
Example 1.44. from_gw usage
...
$var(lcr_id) = from_any_gw("192.168.1.1", 3);
...
4.6. to_gw(lcr_id[, ip_addr, proto])
Checks if in-dialog request goes to IP address and transport protocol
specified for a gateway in LCR instance lcr_id. Fails if LCR instance
includes one or more gateways without IP address. IP address and
transport protocol to be checked are either taken from Request-URI or
(if present) from ip_addr and proto arguments. See from_gw() for more
info regarding the arguments.
Returns 1 on success and -1 on failure and error.
Execution time of to_gw() function is O(log N), where N is number of
gateways in the LCR instance.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
Example 1.45. to_gw usage
...
if (to_gw("1")) {
...
exit;
};
...
4.7. to_any_gw([ip_addr, proto])
Checks if in-dialog request goes to IP address and transport protocol
of any gateway. Only LCR instances, where all gateways have IP address,
are included in the test. IP address and transport protocol to be
checked are either taken from Request-URI or (if present) from ip_addr
and proto arguments. See from_gw() for more info regarding the
arguments.
Execution time of to_any_gw() function is M * O(log N), where M is
number of LCR instances and N is average number of gateways in LCR
instances.
If any gateway has the IP address, returns LCR identifier of the
gateway. Returns -1 if request does not go to a gateway and on error.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
Example 1.46. to_gw usage
...
if (to_any_gw("192.55.66.2", 1)) {
...
exit;
};
...
5. Exported RPC Commands
5.1. lcr.reload
5.2. lcr.dump_gws
5.3. lcr.dump_rules
5.4. lcr.defunct_gw
5.1. lcr.reload
Causes lcr module to re-read the contents of LCR tables into memory.
Name: lcr.reload
Parameters: none
Example 1.47. lcr.reload RPC example
$ kamcmd lcr.reload
5.2. lcr.dump_gws
Causes lcr module to dump the contents of its in-memory gw table.
Parameters: none
Example 1.48. lcr.dump_gws RPC example
$ kamcmd lcr.dump_gws
5.3. lcr.dump_rules
Causes lcr module to dump the contents of its in-memory lcr_rule and
lcr_rule_target tables.
Parameters: none
Example 1.49. lcr.dump_rules RPC example
$ kamcmd lcr.dump_rules
5.4. lcr.defunct_gw
Defuncts gateway loaded into memory for a period of time (seconds)
without a need to store gateway's defunct value into database and
reload the tables.
Name: lcr.defunct_gw
Parameters: lcr_id gw_id period
Example 1.50. lcr.defunct_gw RPC example
$ kamcmd lcr.defunct_gw 1 4 120
6. Known Limitations
In-memory LCR rules and gw tables are switched by two consecutive
machine instructions. If lcr reload process is interrupted after the
first one, in-memory gateway table does not match in-memory rule table
until execution of lcr reload process is resumed.
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