You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
kamailio/modules/htable/README

1019 lines
27 KiB

HTable Module
Elena-Ramona Modroiu
asipto.com
<ramona@rosdev.ro>
Edited by
Elena-Ramona Modroiu
<ramona@rosdev.ro>
Edited by
Alex Balashov
<abalashov@evaristesys.com>
Edited by
Ovidiu Sas
<osas@voipembedded.com>
Copyright © 2008-2011 http://www.asipto.com
__________________________________________________________________
Table of Contents
1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
2.3. Loading from database
3. Parameters
3.1. htable (str)
3.2. db_url (str)
3.3. key_name_column (str)
3.4. key_type_column (str)
3.5. value_type_column (str)
3.6. key_value_column (str)
3.7. expires_column (str)
3.8. array_size_suffix (str)
3.9. fetch_rows (integer)
3.10. timer_interval (integer)
3.11. db_expires (integer)
3.12. enable_dmq (integer)
3.13. timer_procs (integer)
4. Functions
4.1. sht_print()
4.2. sht_rm_name_re(htable=>regexp)
4.3. sht_rm_value_re(htable=>regexp)
4.4. sht_reset(htable)
4.5. sht_lock(htable=>key)
4.6. sht_unlock(htable=>key)
4.7. sht_iterator_start(iname, hname)
4.8. sht_iterator_end(iname)
4.9. sht_iterator_next(iname)
5. Exported pseudo-variables
6. MI Commands
6.1. sht_reload
6.2. sht_dump
6.3. sht_delete
7. Exported RPC Commands
7.1. htable.get htable key
7.2. htable.delete htable key
7.3. htable.sets htable key value
7.4. htable.seti htable key value
7.5. htable.dump htable
7.6. htable.reload htable
7.7. htable.listTables
7.8. htable.stats
8. Event routes
8.1. htable:mod-init
8.2. htable:expired:<table>
List of Examples
1.1. Accessing $sht(htname=>key)
1.2. Dictionary attack limitation
1.3. Storing array values
1.4. Set hash_size parameter
1.5. Set db_url parameter
1.6. Set key_name_column parameter
1.7. Set key_type_column parameter
1.8. Set value_type_column parameter
1.9. Set key_value_column parameter
1.10. Set expires_column parameter
1.11. Set array_size_suffix parameter
1.12. Set fetch_rows parameter
1.13. Set timer_interval parameter
1.14. Set db_expires parameter
1.15. Set enable_dmq parameter
1.16. Set timer_procs parameter
1.17. sht_print usage
1.18. sht_rm_name_re usage
1.19. sht_rm_value_re usage
1.20. sht_reset usage
1.21. sht_lock usage
1.22. sht_unlock usage
1.23. sht_iterator_start usage
1.24. sht_iterator_end usage
1.25. sht_iterator_next usage
Chapter 1. Admin Guide
Table of Contents
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
2.3. Loading from database
3. Parameters
3.1. htable (str)
3.2. db_url (str)
3.3. key_name_column (str)
3.4. key_type_column (str)
3.5. value_type_column (str)
3.6. key_value_column (str)
3.7. expires_column (str)
3.8. array_size_suffix (str)
3.9. fetch_rows (integer)
3.10. timer_interval (integer)
3.11. db_expires (integer)
3.12. enable_dmq (integer)
3.13. timer_procs (integer)
4. Functions
4.1. sht_print()
4.2. sht_rm_name_re(htable=>regexp)
4.3. sht_rm_value_re(htable=>regexp)
4.4. sht_reset(htable)
4.5. sht_lock(htable=>key)
4.6. sht_unlock(htable=>key)
4.7. sht_iterator_start(iname, hname)
4.8. sht_iterator_end(iname)
4.9. sht_iterator_next(iname)
5. Exported pseudo-variables
6. MI Commands
6.1. sht_reload
6.2. sht_dump
6.3. sht_delete
7. Exported RPC Commands
7.1. htable.get htable key
7.2. htable.delete htable key
7.3. htable.sets htable key value
7.4. htable.seti htable key value
7.5. htable.dump htable
7.6. htable.reload htable
7.7. htable.listTables
7.8. htable.stats
8. Event routes
8.1. htable:mod-init
8.2. htable:expired:<table>
1. Overview
The module adds a hash table container to the configuration language.
The hash table is stored in shared memory and the access to it can be
done via pseudo-variables: $sht(htname=>name). The module supports
definition of many hash tables and can load values at startup from a
database table.
A typical use case for the SIP server is to implement a cache system in
configuration file - if a value is not found in hash table, load it
from database and store it in hash table so next time the access to it
is very fast. In the definition of the table you can define the default
expiration time of cached items. The expiration time can be adjusted
per item via assignment operation at runtime.
Replication between multiple servers is performed automatically (if
enabled) via the DMQ module.
You can read more about hash tables at:
http://en.wikipedia.org/wiki/Hash_table.
The “name” can be a static string or can include pseudo- variables that
will be replaced at runtime.
Example 1.1. Accessing $sht(htname=>key)
...
modparam("htable", "htable", "a=>size=8;")
...
$sht(a=>test) = 1;
$sht(a=>$ci::srcip) = $si;
...
Next example shows a way to protect against dictionary attacks. If
someone fails to authenticate 3 times, it is forbidden for 15min.
Authenticatiion against database is expensive as it does a select on
the “subscriberthe” table. By disabling the DB auth for 15min,
resources on the server are saved and time to discover the password is
increased substantially. Additional alerting can be done by writing a
message to syslog or sending email, etc.
To implement the logic, two hash table variables are used: one counting
the failed authentications per user and one for storing the time of
last authentication attempt. To ensure a unique name per user, the hash
table uses a combination of authentication username and text
“::auth_count” and “::last_auth”.
Example 1.2. Dictionary attack limitation
...
modparam("htable", "htable", "a=>size=8;")
...
if(is_present_hf("Authorization"))
{
if($sht(a=>$au::auth_count)==3)
{
$var(exp) = $Ts - 900;
if($sht(a=>$au::last_auth) > $var(exp))
{
sl_send_reply("403", "Try later");
exit;
} else {
$sht(a=>$au::auth_count) = 0;
}
}
if(!www_authenticate("$td", "subscriber"))
{
switch ($retcode) {
case -1:
sl_send_reply("403", "Forbidden");
exit;
case -2:
if($sht(a=>$au::auth_count) == $null)
$sht(a=>$au::auth_count) = 0;
$sht(a=>$au::auth_count) = $sht(a=>$au::auth_count) + 1;
if($sht(a=>$au::auth_count) == 3)
xlog("auth failed 3rd time - src ip: $si\n");
$sht(a=>$au::last_auth) = $Ts;
break;
}
www_challenge("$td"/*realm*/,"0"/*qop*/);
exit;
}
$sht(a=>$au::auth_count) = 0;
} else {
www_challenge("$td","0");
exit;
}
...
The module also provides a way to store multiple values for a single
key. This is emulated by storing individual keys as 'key_name[n]',
where n is incremented for each key. The total number of keys is stored
in a dedicated key, by default: 'key_name::size'.
The array is built when the table is loaded in memory and afterwards
all the keys are treated as individual keys. If a particular entry in
the array is deleted, it is the administrator's responsibility to
update the size of the array and any other elements (if required).
Example 1.3. Storing array values
# Example of dbtext with multiple keys
$ cat /usr/local/etc/kamailio/dbtext/htable
1:key:1:0:value3:0
2:key:1:0:value2:0
3:key:1:0:value1:0
# The array key will be loaded in memory in the following format:
$ kamcmd htable.dump htable
{
entry: 35
size: 1
slot: {
item: {
name: key[0]
value: value1
}
}
}
{
entry: 50
size: 1
slot: {
item: {
name: key::size
value: 3
}
}
}
{
entry: 67
size: 1
slot: {
item: {
name: key[1]
value: value2
}
}
}
{
entry: 227
size: 1
slot: {
item: {
name: key[2]
value: value3
}
}
}
# Now let's delete a particular entry in the array: key[0].
$ kamcmd htable.delete htable key[0]
# The array key will look like this after a key was deleted:
$ kamcmd htable.dump htable
{
entry: 50
size: 1
slot: {
item: {
name: key::size
value: 3
}
}
}
{
entry: 67
size: 1
slot: {
item: {
name: key[1]
value: value2
}
}
}
{
entry: 227
size: 1
slot: {
item: {
name: key[2]
value: value3
}
}
}
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
2.3. Loading from database
2.1. Kamailio Modules
The following modules must be loaded before this module:
* If DMQ replication is enabled, the DMQ module must be loaded
first..
2.2. External Libraries or Applications
The following libraries or applications must be installed before
running Kamailio with this module loaded:
* None.
2.3. Loading from database
The module is able to load values in a hash table at startup upon
providing a DB URL and table name.
The structure of the table must contain:
* key name - string containing the name of the key.
* key type - the type of the key
+ 0 - simple key - the key is added as 'key_name'.
+ 1 - array key - the key is added as 'key_name[n]' - n is
incremented for each key with this name to build an array in
hash table. In addition, an additional key is built to hold
the total number of key in the array, by default
key_name::size (see array_size_suffix parameter).
* value type - the type of the key value
+ 0 - value is string.
+ 1 - value is integer.
* key value - string containing the value of the key.
3. Parameters
3.1. htable (str)
3.2. db_url (str)
3.3. key_name_column (str)
3.4. key_type_column (str)
3.5. value_type_column (str)
3.6. key_value_column (str)
3.7. expires_column (str)
3.8. array_size_suffix (str)
3.9. fetch_rows (integer)
3.10. timer_interval (integer)
3.11. db_expires (integer)
3.12. enable_dmq (integer)
3.13. timer_procs (integer)
3.1. htable (str)
The definition of a hash table. The value of the parameter may have the
following format:
* "htname=>size=_number_;autoexpire=_number_;dbtable=_string_"
The parameter can be set multiple times to get more hash tables in same
configuration file.
* htname - string specifying the name of the hash table. This string
is used by $sht(...) to refer to the hash table.
* size - number specifying the size of hash table. Larger value means
less collisions. The number of entries (aka slots or buckets) in
the table is 2^size. The possible range for this value is from 2 to
31, smaller or larger values will be increased to 3 (8 slots) or
decreased to 14 (16384 slots).
* autoexpire -time in seconds to delete an item from hash table if no
update was done to it. If is missing or set to 0, the items won't
expire.
* dbtable - name of database to be loaded at startup in hash table.
If empty or missing, no data will be loaded.
* cols - the column names of the database table. They must be
enclosed in quotes in order to form a valid SIP parameter value and
be separated by comma. The first column corresponds to key_name.
When specified, there must be at least two columns. If this
attribute is not specified, then the global module parameters for
column names are used. If more than one value columns are
specified, the hash table will pack the column values in a comma
separated string, which will be associated with the key (string
transformation {s.select,...} can be used in configuration file to
extract a specific column value). When cols attribute is present,
writing back to database table is disabled.
* dbmode - if set to 1, the content of hash table is written to
database table when the SIP server is stopped (i.e., ensure
persistency over restarts). Default value is 0 (no write back to db
table).
* initval - the integer value to be returned instead of $null when a
requested key is not set.
* updateexpire - if set to 1 (default), the time until expiration of
an item is reset when that item is updated. Certain uses of htable
may dictate that updates should not reset the expiration timeout,
however, in which case this attribute can be set to 0.
* dmqreplicate - if set to 1, any actions (set, update, delete etc.)
performed upon entries in this table will be replicated to other
nodes (htable peers). Please note, module parameter “enable_dmq”
must also be set in order for this to apply (see below). Default is
0 (no replication).
Default value is NULL.
Example 1.4. Set hash_size parameter
...
modparam("htable", "htable", "a=>size=4;autoexpire=7200;dbtable=htable_a;")
modparam("htable", "htable", "b=>size=5;")
modparam("htable", "htable", "c=>size=4;autoexpire=7200;initval=1;dmqreplicate=1
;")
...
3.2. db_url (str)
The URL to connect to database for loading values in hash table at
start up.
Default value is NULL (do not connect).
Example 1.5. Set db_url parameter
...
modparam("htable", "db_url", "mysql://kamailio:kamailiorw@localhost/kamailio")
...
3.3. key_name_column (str)
The name of the column containing the hash table key name.
Default value is 'key_name'.
Example 1.6. Set key_name_column parameter
...
modparam("htable", "key_name_column", "kname")
...
3.4. key_type_column (str)
The name of the column containing the hash table key type.
Default value is 'key_type'.
Example 1.7. Set key_type_column parameter
...
modparam("htable", "key_type_column", "ktype")
...
3.5. value_type_column (str)
The name of the column containing the hash table value type.
Default value is 'value_type'.
Example 1.8. Set value_type_column parameter
...
modparam("htable", "value_type_column", "vtype")
...
3.6. key_value_column (str)
The name of the column containing hash table key value.
Default value is 'key_value'.
Example 1.9. Set key_value_column parameter
...
modparam("htable", "key_value_column", "kvalue")
...
3.7. expires_column (str)
The name of the column containing the expires value.
Default value is 'expires'.
Example 1.10. Set expires_column parameter
...
modparam("htable", "expires", "expiry")
...
3.8. array_size_suffix (str)
The suffix to be added to store the number of items in an array (see
key type).
Default value is '::size'.
Example 1.11. Set array_size_suffix parameter
...
modparam("htable", "array_size_suffix", "-count")
...
3.9. fetch_rows (integer)
How many rows to fetch at once from database.
Default value is 100.
Example 1.12. Set fetch_rows parameter
...
modparam("htable", "fetch_rows", 1000)
...
3.10. timer_interval (integer)
Interval in seconds to check for expired htable values.
Default value is 20.
Example 1.13. Set timer_interval parameter
...
modparam("htable", "timer_interval", 10)
...
3.11. db_expires (integer)
If set to 1, the module will load/save the expires values of the items
in hash table from/to database. It applies only to hash tables that
have the auto-expires attribute defined.
Default value is 0.
Example 1.14. Set db_expires parameter
...
modparam("htable", "db_expires", 1)
...
3.12. enable_dmq (integer)
If set to 1, will enable DMQ replication of actions performed upon
entries in all tables having "dmqreplicate" parameter set. Any update
action performed via pseudo-variables, MI and RPC commands will be
repeated on all other nodes. Therefore, it is important to ensure the
table definition (size, autoexpire etc.) is identical across all
instances.
Important: If this parameter is enabled, the DMQ module must be loaded
first - otherwise, startup will fail.
Currently, values are not replicated on load from DB as it is expected
that in these cases, all servers will load their values from the same
DB.
Default value is 0.
Example 1.15. Set enable_dmq parameter
...
modparam("htable", "enable_dmq", 1)
...
3.13. timer_procs (integer)
If set to 1 or greater, the module will create its own timer processes
to scan for expired items in hash tables. If set to zero, it will use
the core timer for this task. Set it to 1 if you store a lot of items
with autoexpire property.
Default value is 0.
Example 1.16. Set timer_procs parameter
...
modparam("htable", "timer_procs", 4)
...
4. Functions
4.1. sht_print()
4.2. sht_rm_name_re(htable=>regexp)
4.3. sht_rm_value_re(htable=>regexp)
4.4. sht_reset(htable)
4.5. sht_lock(htable=>key)
4.6. sht_unlock(htable=>key)
4.7. sht_iterator_start(iname, hname)
4.8. sht_iterator_end(iname)
4.9. sht_iterator_next(iname)
4.1. sht_print()
Dump content of hash table to L_ERR log level. Intended for debug
purposes.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
ONREPLY_ROUTE, BRANCH_ROUTE.
Example 1.17. sht_print usage
...
sht_print();
...
4.2. sht_rm_name_re(htable=>regexp)
Delete all entries in the htable that match the name against regular
expression.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
ONREPLY_ROUTE, BRANCH_ROUTE.
Example 1.18. sht_rm_name_re usage
...
sht_rm_name_re("ha=>.*");
...
4.3. sht_rm_value_re(htable=>regexp)
Delete all entries in the htable that match the value against regular
expression.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
ONREPLY_ROUTE, BRANCH_ROUTE.
Example 1.19. sht_rm_value_re usage
...
sht_rm_value_re("ha=>.*");
...
4.4. sht_reset(htable)
Delete all entries in the htable. The name of the hash table can be a
dynamic string with variables.
This function can be used from ANY_ROUTE.
Example 1.20. sht_reset usage
...
sht_reset("ha$var(x)");
...
4.5. sht_lock(htable=>key)
Lock the slot in htable corespoding to the key item. Note that the
locking is re-entrant for the process, therefore the lock and unlock
should be done by the same process.
This function can be used from ANY_ROUTE.
Example 1.21. sht_lock usage
...
sht_lock("ha=>test");
...
4.6. sht_unlock(htable=>key)
Unlock the slot in htable corespoding to the key item. Note that the
locking is re-entrant for the process, therefore the lock and unlock
should be done by the same process.
This function can be used from ANY_ROUTE.
Example 1.22. sht_unlock usage
...
sht_lock("ha=>test");
$sht(ha=>test) = $sht(ha=>test) + 10;
sht_unlock("ha=>test");
...
4.7. sht_iterator_start(iname, hname)
Start an iterator for hash table named by the value of parameter hname.
The parameter iname is used to identify the iterator. There can be up
to 4 iterators at the same time, with different name.
Both parameters can be dynamic strings with variables.
IMPORTANT: the slot of the hash table is left locked when retrieving in
item. Therefore be sure you do not update the content of the hash table
in between sht_iterator_start() and sht_iterator_end(), because it may
end up in dead lock.
This function can be used from ANY_ROUTE.
Example 1.23. sht_iterator_start usage
...
sht_iterator_start("i1", "h1");
...
4.8. sht_iterator_end(iname)
Close the iterator identified by iname parameter and release the hash
table slot aquired by the iterator. The iname value must be the same
used for sht_iterator_start().
The parameter can be dynamic string with variables.
This function can be used from ANY_ROUTE.
Example 1.24. sht_iterator_end usage
...
sht_iterator_end("i1");
...
4.9. sht_iterator_next(iname)
Move the iterator to the next item in hash table. It must be called
also after sht_iterator_start() to get the first item in the hash
table. Items are returned as they are found in the hash table slot,
starting with the first slot.
The return code is false when there is no (more) item in the hash
table.
The item name and value are accessible via variables: $shtitkey(iname)
and $shtitval(iname).
The parameter can be dynamic string with variables.
This function can be used from ANY_ROUTE.
Example 1.25. sht_iterator_next usage
...
sht_iterator_start("i1", "h1");
while(sht_iterator_next("i1")) {
xlog("h1[$shtitkey(i1)] is: $shtitval(i1)\n");
}
sht_iterator_end("i1");
...
5. Exported pseudo-variables
* $sht(htable=>key)
* $shtex(htable=>key)
* $shtcn(htable=>key)
* $shtcv(htable=>key)
* $shtinc(htable=>key)
* $shtitkey(iname)
* $shtitval(iname)
* $shtrecord(attribute)
Exported pseudo-variables are documented at
http://www.kamailio.org/wiki/.
6. MI Commands
6.1. sht_reload
6.2. sht_dump
6.3. sht_delete
6.1. sht_reload
Reload a hash table from database.
Name: sht_reload
Parameters: _hash_table_name_ - the name of hash table to reload.
MI FIFO Command Format:
:sht_reload:_reply_fifo_file_
_hash_table_name_
_empty_line_
6.2. sht_dump
Dump content of a hash table via MI.
Name: sht_dump
Parameters: _hash_table_name_ - the name of hash table to dump.
MI FIFO Command Format:
:sht_dump:_reply_fifo_file_
_hash_table_name_
_empty_line_
6.3. sht_delete
Delete a key from a hash table via MI.
Name: sht_delete
Parameters:
* _hash_table_name: The table name to delete the key from
* _key_name: The key to delete from the htable
MI FIFO Command Format:
:sht_delete:_reply_fifo_file_
_hash_table_name_
_key_name_
_empty_line_
Example (note the quoting when executing it via FIFO):
kamctl fifo sht_delete auth '"user@example.org::last_auth"'
7. Exported RPC Commands
7.1. htable.get htable key
7.2. htable.delete htable key
7.3. htable.sets htable key value
7.4. htable.seti htable key value
7.5. htable.dump htable
7.6. htable.reload htable
7.7. htable.listTables
7.8. htable.stats
7.1. htable.get htable key
Lists one value in a hash table
Name: htable.get
Parameters:
* htable : Name of the hash table to dump
* key : Key name of the hash table value to dump
Example:
...
# Dump $sht(students=>daniel)
kamcmd htable.get students daniel
# Dump first entry in array key course $sht(students=>course[0])
kamcmd htable.get students course[0]
...
7.2. htable.delete htable key
Delete one value in a hash table
Name: htable.delete
Parameters:
* htable : Name of the hash table to delete
* key : Key name of the hash table value to delete
Example:
...
# Delete $sht(students=>anna)
kamcmd htable.delete students anna
# Delete first entry in array key course $sht(students=>course[0])
kamcmd htable.delete students course[0]
...
7.3. htable.sets htable key value
Set an item in hash table to string value.
Name: htable.sets
Parameters:
* htable : Name of the hash table
* key : Key name in the hash table
* Value : String value for the item
Example:
...
# Set $sht(test=>x) as string
kamcmd htable.sets test x abc
# Set firsti entry in array key x $sht(test=>x[0]) as string
kamcmd htable.sets test x[0] abc
...
7.4. htable.seti htable key value
Set an item in hash table to integer value.
Name: htable.seti
Parameters:
* htable : Name of the hash table
* key : Key name in the hash table
* Value : Integer value for the item
Example:
...
# Set $sht(test=>x) as integer
kamcmd htable.seti test x 123
# Set firsti entry in array key x $sht(test=>x[0]) as integer
kamcmd htable.sets test x[0] 123
...
7.5. htable.dump htable
Lists all the values in a hash table
Name: dhtable.dump
Parameters:
* htable : Name of the hash table to dump
Example:
...
kamcmd htable.dump ipban
...
7.6. htable.reload htable
Reload hash table from database.
Name: dhtable.reload
Parameters:
* htable : Name of the hash table to reload
Example:
...
kamcmd htable.reload ipban
...
7.7. htable.listTables
Lists all defined tables
Name: htable.listTables
Parameters:
* None
Example:
...
kamcmd htable.listTables
...
7.8. htable.stats
Get statistics for hash tables - name, number of slots, number of
items, max number of items per slot, min number of items per slot.
Name: htable.stats
Parameters:
* None
Example:
...
kamcmd htable.stats
...
8. Event routes
8.1. htable:mod-init
8.2. htable:expired:<table>
8.1. htable:mod-init
When defined, the module calls event_route[htable:mod-init] after all
modules have been initialized. A typical use case is to initialise
items in hash tables. The event route is executed only once, after core
and module initialization, but before Kamailio forks any child
processes.
...
event_route[htable:mod-init] {
$sht(a=>x) = 1;
}
...
8.2. htable:expired:<table>
When defined, the module calls event_route[htable:expired:<table>] when
an entry in the given table expires. In this event route, the key and
value of the expired record are available with the $shtrecord(key) and
$shtrecord(value) pseudo-variables.
...
event_route[htable:expired:mytable] {
xlog("mytable record expired $shtrecord(key) => $shtrecord(value)\n");
}
...