philologist's techblog

Linux: limit CPU usage by running process

July 18th, 2016

Use cpulimit for this.

We have a 8-core CPU (it means the total CPU usage can be 800%, and 100% for 1 core respectively).
Our process is ‘raid-check’.

/usr/bin/cpulimit --exe /usr/sbin/raid-check --limit 600

I added this line to crontab config. The reason is that my Asterisk stops accepting calls when the CPU load is too high. Of course you can also use asterisk.conf settings to achieve the desired results.

[root@voip-ge ~]# cat /etc/cron.d/raid-check # Run system wide raid-check once a week on Sunday at 1am by default 0 1 * * Mon root /usr/sbin/raid-check

# limit the CPU usage by executable name 1 1 * * Mon root /usr/bin/cpulimit --exe /usr/sbin/raid-check --limit 600

Tags: cpulimit
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SSH port forwarding

July 16th, 2016

Assuming, MySQL is running on ‘remoteserver’ on 127.0.0.1:3306, and you have only SSH access to the remote server.

lexus@lexus:~$ ssh user@remote-server -L 3306:127.0.0.1:3306 -N
support@remote-server’s password: (press Ctrl-Z)
^Z
[1]+ Stopped ssh user@remote-server -L 3306:127.0.0.1:3306 -N
lexus@lexus:~$ bg
[1]+ ssh user@remote-server -L 3306:127.0.0.1:3306 -N &
lexus@lexus:~$ mysql -h 127.0.0.1 -p -u sqluser
Enter password:

Tags: port fowarding, ss
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Ubuntu: old releases repositories

July 8th, 2016

If your Ubuntu is too old and aptitude stopped working, showing 404 not found.

Add this to /etc/apt/sources.list, changing the CODENAME to your Ubuntu version.

## EOL upgrade sources.list # Required deb http://old-releases.ubuntu.com/ubuntu/ CODENAME main restricted universe multiverse deb http://old-releases.ubuntu.com/ubuntu/ CODENAME-updates main restricted universe multiverse deb http://old-releases.ubuntu.com/ubuntu/ CODENAME-security main restricted universe multiverse

# Optional #deb http://old-releases.ubuntu.com/ubuntu/ CODENAME-backports main restricted universe multiverse

That’s enough.
Read more if you’re interested in.
https://help.ubuntu.com/community/EOLUpgrades
http://old-releases.ubuntu.com/releases/

Tags: apt, aptitude, ubuntu, upgrade
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Asterisk: ODBC configuration files relations

June 6th, 2016

https://wiki.asterisk.org/wiki/display/AST/Getting+Asterisk+Connected+to+MySQL+via+ODBC
https://wiki.asterisk.org/wiki/display/AST/Configuring+res_odbc

odbcinst.ini
===================

[MySQL]
Description = ODBC for MySQL
Driver = /usr/lib/odbc/libmyodbc.so
Setup = /usr/lib/odbc/libodbcmyS.so
FileUsage = 1

odbc.ini
===============

[asterisk-connector]
Description	= MySQL connection to 'asterisk' database
Driver = MySQL
Database = asterisk
Server = localhost
Port = 3306
Socket = /var/lib/mysqld/mysqld.sock

res_odbc.conf
====================

[asterisk]
enabled => yes
dsn => asterisk-connector	// points to DB connection in odbc.ini
username => asterisk
password => welcome
pooling => no
limit => 1
pre-connect => yes

cdr_adaptive_odbc.conf
==============================

connection = asterisk // The database connection to be used. This is a reference 
                      // to the configured connection in res_odbc.conf. This field is required.
table = // The table name. This field is required.

Tags: asterisk, odbc
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AcmePacket: go on rejecting!

May 19th, 2016

One more post about INVITE rejecting.

The task: reject malicious SIP traffic coming from some country to our number. All INVITEs contain a From: header with 12-digits number starting with 666. The may also contain a plus sign at the beginning or 810, or +810.

It is also important to set a ‘new-value’ parameter, containing a status code and SIP description (in form of “Code:Description”), as some (or maybe most) PBXses/softswitches/proxies go on sending INVITEs if we just do ‘action reject’. After answering from AcmePacket with something like “403 Forbidden” the remote side stops sending endless INVITEs to AcmePacket.

Part of sip-manipulation:

        header-rule
                name                                    dropHACKERS
                header-name                             From
                action                                  manipulate
                comparison-type                         pattern-rule
                msg-type                                any
                methods                                 INVITE
                match-value                             
                new-value                               
                element-rule
                        name                                    dropHACKERS1
                        parameter-name                          From
                        type                                    uri-phone-number-only
                        action                                  reject
                        match-val-type                          any
                        comparison-type                         pattern-rule
                        match-value                             666[0-9]{9}$
                        new-value                               403:Forbidden

This is how it looks like after rejecting malicious INVITE with “403 Forbidden”:

Tags: acme, acme packet, acmepacket
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SQL: get the database size

March 25th, 2016

I’m going on writing primitive posts about the fascinating world of relational database management systems. :)

MySQL, size of all databases:

mysql> SELECT table_schema \
       "Database name", \
       sum( data_length + index_length ) / 1024 / 1024 \
       "Data Base Size in MB" FROM \
       information_schema.TABLES GROUP BY table_schema;
+--------------------+----------------------+
| Database name      | Data Base Size in MB |
+--------------------+----------------------+
| fluxbb             |           0.04585648 |
| information_schema |           0.00781250 |
| mysql              |           0.60614872 |
| wordpress          |           2.22493362 |
+--------------------+----------------------+
4 rows in set (0.13 sec)

PostgreSQL, size of all databases:

cdr=> SELECT pg_database.datname,pg_size_pretty(pg_database_size(pg_database.datname)) \
      AS size FROM pg_database;
  datname  |  size   
-----------+---------
 template1 | 6705 kB
 template0 | 6697 kB
 postgres  | 6820 kB
 cdr       | 28 GB

Size of ‘acme_cdr’ table:

cdr=> SELECT pg_size_pretty(pg_total_relation_size('acme_cdr'));
 pg_size_pretty 
----------------
 28 GB

Tags: mysql, postgresql, sql
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ngrep: SIP traffic analyze

March 1st, 2016

tcpdump is a nice tool, but some filters seem to be too complicated for usage.

It’s quite simple to look at SIP traffic between our server and remote server with tcpdump:
tcpdump -pni eth0 udp and port 5060 and host 1.2.3.4

… or a little bit more verbose:
tcpdump -pni eth0 -v udp and port 5060 and host 1.2.3.4

… or even:
tcpdump -pni eth0 -v -As0 udp and port 5060 and host 1.2.3.4

But how to capture only INVITE messages?
This is the case to use ngrep:

root@voip-ge:~# ngrep -W byline "INVITE sip" port 5060 and host zz.nn.159.114
interface: eth0 (10.219.3.0/255.255.255.0)
filter: (ip or ip6) and ( port 5060 and host zz.nn.159.114 )
match: INVITE sip
#
U xx.yy.94.130:5060 -> zz.nn.159.114:5060
INVITE sip:412753@zz.nn.159.114 SIP/2.0.
v: SIP/2.0/UDP xx.yy.94.130:5060;branch=z9hG4bK51d42193.
Max-Forwards: 70.
f: "SomeCallerID" sip:0606@xx.yy.94.130;tag=as07e569d2.
t: sip:412753@zz.nn.159.114.
m: sip:0606@xx.yy.94.130:5060.
i: 795031de44fe066e3751fdc6218368e7@xx.yy.94.130:5060.
CSeq: 102 INVITE.
User-Agent: Cisco-SIPGateway/IOS-12.x.
Date: Tue, 01 Mar 2016 07:05:13 GMT.
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE.
k: replaces.
c: application/sdp.
l: 299.
.
v=0.
o=CiscoSystemsSIP-GW-UserAgent 886157825 886157825 IN IP4 xx.yy.94.130.
s=SIP Call.
c=IN IP4 xx.yy.94.130.
t=0 0.
m=audio 19504 RTP/AVP 8 0 101.
a=rtpmap:8 PCMA/8000.
a=rtpmap:0 PCMU/8000.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-16.
a=silenceSupp:off - - - -.
a=ptime:20.
a=sendrecv.

Tags: ngrep, tcpdump
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acmepacket: import/export HMR

February 9th, 2016

conf t -> session-router -> sip-manipulation

Select some HMR and then do:

export %filename%

After that a %filename%.gz will appear under /code/imports/ directory. And you can download it via FTP/SFTP.

It is also possible to import sip-manipulation rules. Put your .gz file with the same structure to /code/imports/ , then go to conf t -> session-router -> sip-manipulation and do:

import %filename%.gz

Tags: acme, acme packet, acmepacket, hmr, oracle, oracle sbc, sbc, voip
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sed: add line starting with 2 tabs before another matching line

February 5th, 2016

Add a line Sipaddheader(X-DSTPHONE:${E}); before lines containing zabbix.

sed '/zabbix/a Sipaddheader(X-DSTPHONE:${E});' extensions.ael > extensions2.ael

Add the same but starting with 2 tabs seems to be not hard. But the problem is that not all sed versions support \t parameter.

So, neither of these worked for me:

sed '/zabbix/a \t\tSipaddheader(X-DSTPHONE:${E});' extensions.ael > extensions2.ael

sed '/zabbix/a \t\t Sipaddheader(X-DSTPHONE:${E});' extensions.ael > extensions2.ael

sed '/zabbix/a\t\t Sipaddheader(X-DSTPHONE:${E});' extensions.ael > extensions2.ael

The solution is as follows: insert a literal tab pressing Ctrl-V and then Tab (not shown in the listing).

Tags: sed
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Asterisk: Queue statistics

January 29th, 2016

As it’s said in queues.conf:

  ; If set to yes, the following variables will be set
  ; just prior to the caller being bridged with a queue member
  ; and just prior to the caller leaving the queue
  ; QUEUENAME name of the queue
  ; QUEUEMAX maxmimum number of calls allowed
  ; QUEUESTRATEGY the strategy of the queue;
  ; QUEUECALLS number of calls currently in the queue
  ; QUEUEHOLDTIME current average hold time
  ; QUEUECOMPLETED number of completed calls for the queue
  ; QUEUEABANDONED number of abandoned calls
  ; QUEUESRVLEVEL queue service level
  ; QUEUESRVLEVELPERF current service level performance
  ;
  ;setqueuevar=no

So, add ‘setqueuevar=yes’ to each queue definition in queues.conf and then modify your dialplan after execution of the Queue application:

  Queue(${EXTEN},t,,,25);

  // to enable Queue statistics
  NoOp(${QUEUE_VARIABLES(${EXTEN})});

  NoOp(QUEUESTRATEGY is ${QUEUESTRATEGY});
  NoOp(QUEUECALLS is ${QUEUECALLS});
  NoOp(QUEUEHOLDTIME is ${QUEUEHOLDTIME});
  NoOp(QUEUECOMPLETED is ${QUEUECOMPLETED});
  NoOp(QUEUEABANDONED is ${QUEUEABANDONED});
  NoOp(QUEUESRVLEVEL is ${QUEUESRVLEVEL});
  NoOp(QUEUESRVLEVELPERF is ${QUEUESRVLEVELPERF})

Console output:

  Executing [007@inc:33] NoOp("007@inc-1658;2", "0") in new stack
  Executing [007@inc:34] NoOp("007@inc-1658;2", "QUEUESTRATEGY is ringall") in new stack
  Executing [007@inc:35] NoOp("007@inc-1658;2", "QUEUECALLS is 0") in new stack
  Executing [007@inc:36] NoOp("007@inc-1658;2", "QUEUEHOLDTIME is 6") in new stack
  Executing [007@inc:37] NoOp("007@inc-1658;2", "QUEUECOMPLETED is 12778") in new stack
  Executing [007@inc:38] NoOp("007@inc-1658;2", "QUEUEABANDONED is 34844") in new stack
  Executing [007@inc:39] NoOp("007@inc-1658;2", "QUEUESRVLEVEL is 10") in new stack
  Executing [007@inc:40] NoOp("007@inc-1658;2", "QUEUESRVLEVELPERF is 54.6") in new stack

Tags: asterisk, queue, queues, queues.conf
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