philologist's techblog

AcmePacket: reject redirected calls

February 20th, 2015

What to do if somebody set up call redirect from his number to yours one, but you do not want to accept such calls?

According to RFC5806 – Diversion Indication in SIP,

The Diversion header SHOULD be added when a SIP proxy server, SIP
redirect server, or SIP user agent changes the ultimate endpoint that
will receive the call.

So, you have to reject INVITEs with Diversion header. This is how it looks like on the AcmePacket. One more header-rule (if you already have any) in sip-manipulation rule:

header-rule
	name                           reject_diversion
	header-name                    Diversion
	action                         manipulate
	comparison-type                case-sensitive
	msg-type                       request
	methods                        INVITE
	match-value                    
	new-value                      
	element-rule
		name                           rej_diversion
		parameter-name                 
		type                           header-value
		action                         reject
		match-val-type                 any
		comparison-type                pattern-rule
		match-value                    ^.*$
		new-value

You may also add something like “603:Decline” to “new-value” parameter.

Or even like this, without any responce codes and element-rules:

header-rule
                name                                    rejectDiversion
                header-name                             Diversion
                action                                  reject
                comparison-type                         boolean
                msg-type                                request
                methods                                 INVITE
                match-value                             
                new-value

Tags: acmepacket, diversion, hmr, sbc
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tmux

February 19th, 2015

tmux – start tmux
Ctrl-b and then c – create new virtual screen
Ctrl-b and then w – list created virtual screens (windows), select with arrow keys
Ctrl-b and then [ – start scrolling mode. Scroll with PageUp and PageDown, ‘q’ to leave scrolling mode.
exit or Ctrl-d – close virtual screen

A nice article from my hotly favourite OpenBSD project.

Tags: tmux
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Small console utils

January 24th, 2015

ee – easy to use text editor
le – text editor inspired by Norton Commander
lookat – user-friendly text pager
moe – powerful and user-friendly console text editor
ne – nice console editor
ranger – minimalistic console file manager

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MySQL: myisamchk

January 12th, 2015

Decided to get better knowledge of MySQL with crawling on http://dev.mysql.com/doc/refman/YOUR_VERSION/en/ , for example http://dev.mysql.com/doc/refman/5.7/en/ .

Before MySQL 5.5.5, MyISAM was the default storage engine. (The default was changed to InnoDB in MySQL 5.5.5.)
One of my deployments uses MySQL version prior to 5.5.5. While reading the documentation I found a nice utility, ‘myisamchk‘ and instantly decided to check with it one of *.MYI files. I was a little bit astonished when the utilite showed me some problems with one of files, while everything worked fine. This is the silent mode, only errors (if found) are showed:

root@zenwalk:~# myisamchk -s /var/lib/mysql/webapp/doityourself.MYI
myisamchk: MyISAM file /var/lib/mysql/webapp/doityourself.MYI
myisamchk: warning: 12 clients are using or haven't closed the table properly
MyISAM-table '/var/lib/mysql/webapp/doityourself.MYI' is usable but should be fixed

Normal mode:

root@zenwalk:~# myisamchk /var/lib/mysql/webapp/doityourself.MYI
Checking MyISAM file: /var/lib/mysql/webapp/doityourself.MYI
Data records:     170   Deleted blocks:       2
myisamchk: warning: 12 clients are using or haven't closed the table properly
- check file-size
- check record delete-chain
- check key delete-chain
- check index reference
- check data record references index: 1
- check data record references index: 2
- check record links
MyISAM-table '/var/lib/mysql/webapp/doityourself.MYI' is usable but should be fixed

So, let’s recover the .MYI file. Fire!

root@zenwalk:~# myisamchk --recover /var/lib/mysql/webapp/doityourself.MYI
- recovering (with sort) MyISAM-table '/var/lib/mysql/webapp/doityourself.MYI'
Data records: 170
- Fixing index 1
- Fixing index 2

Tags: myisam, myisamchk, mysql, sql
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AcmePacket: session constraints

December 31st, 2014

# show sessions or # monitor session gives you a whole statistics of active sessions on your session director.

What to do if you want to see the number of sessions on each session-agent? Use # show sipd agents

This extremely useful command can help you to destinguish the suspiciously high (for your network) connections count on a concrete session-agent. And you will see the problem agent while being DDoSed or under real high load. Or just see sessions per session-agent.

# show sessions
The left column shows the number of active sessions on your Session Director. The right one demonstrates the highest number of sessions ever been on SD:

This is how # show sipd agents looks like:

The letter I in the second column means that the session agent is ‘in service’.
The letter O means that it’s ‘out of service’, unused.
The letter C means that constraints are configured and are used right now: the number of sessions is higher than allowed. The ‘Active’ column shows the number of sessions. The column ‘ConEx’ is ‘Constraints exceeded’ – the number of ignored due to the limitations sessions for the last 100 seconds.
As you can see, session-agents may be inbound and outbound. In this example we see only inbound, they are peers with SIP providers. The outbound are peers with Asterisk nodes in the core of the network, they also have such statistics.

It is possible to see a detailed statistics for any of the configured session-agents:
# show sipd agents %ip address% or # show sipd agents %session-agent name%
Have a look at session-agent which is marked with I letter (in service):

And one more example for the session-agent with ConEx – constraints exceeded:

Constraints can be configured either in # configure terminal -> session-router -> session-constraints and then applying them variant_1) on the sip-interface (# configure terminal -> session-router -> sip-interface -> constraint-name), variant_2) on a realm (# conf t -> media-manager -> realm-config), or for the session-agent directly.

Here’s an example of a directly applied (but disabled) constraint on a session-agent:

Just be sure to set ‘constraints enabled‘ in your session-agent, not only the value, otherwise they will not be applied.

Tags: acme packet, acmepacket, constraints
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Asterisk: asterisk dead but subsys locked

September 23rd, 2014

Problem: After successful installation from source (CentOS 6.5 x86_64, Asterisk 11.12.1) you get:

root@twt [~]# service asterisk status asterisk is stopped root@twt [~]# service asterisk start Starting asterisk: root@twt [~]# service asterisk status asterisk dead but subsys locked root@twt [~]# asterisk -rv asterisk: error while loading shared libraries: libasteriskssl.so.1: cannot open shared object file: No such file or directory

Solution:
ln -s /usr/lib/libasteriskssl.so.1 /usr/lib64/libasteriskssl.so.1

Tags: asterisk, asterisk errors, errors
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Unix shell: list directories only

June 27th, 2014

A simple question with the answer not so simple to find.
For a current directory:

lexus@lexus:~$ ls -dl */
drwxr-xr-x 16 lexus lexus 4096 Apr  1 16:16 KAZANTSEV/
drwxrwxr-x  3 lexus lexus 4096 Aug  5  2013 Storage/
drwxrwxr-x  2 lexus lexus 4096 Feb  9  2012 Ubuntu One/
drwxr-xr-x 11 lexus lexus 4096 Jan  3 17:14 VirtualBox VMs/
drwxrwxr-x  2 lexus lexus 4096 Jun 10 17:09 dbn/
drwxr-xr-x  2 lexus lexus 4096 Jan 10 10:41 dwhelper/
drwxr-xr-x  3 lexus lexus 4096 May  2  2012 fluxmenu/
drwxr-xr-x  2 lexus lexus 4096 Feb  5 15:28 fontconfig/
drwxrwxr-x  2 lexus lexus 4096 Apr 18 17:24 images/
drwxr-xr-x  6 lexus lexus 4096 Oct 31  2013 sipvicious-0.2.8/
lexus@lexus:~$

For some other directory:

lexus@lexus:~$ ls -dl /tmp/*/
drwx------ 2 lexus lexus 4096 May 30 07:08 /tmp/CRX_75DAF8CB7768/
drwx------ 2 lexus lexus 4096 Jun 26 12:23 /tmp/acroread_1000_1000/
drwxr-xr-x 2 lexus lexus 4096 Jun 18 16:52 /tmp/hsperfdata_lexus/
drwx------ 2 lexus lexus 4096 Jun 25 18:36 /tmp/libgksu-lBNuPo/
drwx------ 2 lexus lexus 4096 Jun  6 14:57 /tmp/mc-lexus/
drwx------ 2 lexus lexus 4096 Jan  1  1970 /tmp/orbit-lexus/
drwx------ 2 root  root  4096 Jan  1  1970 /tmp/orbit-root/
drwx------ 2 lexus lexus 4096 Jun 11 16:48 /tmp/plugtmp/
drwx------ 2 lexus lexus 4096 May 26 17:59 /tmp/ssh-ftcIDV2jxXYG/
drwx------ 2 lexus lexus 4096 May 26 17:59 /tmp/ssh-tzuelndrwY3i/
lexus@lexus:~$

Tags: ls
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Brute your trunks, dial out

June 27th, 2014

A small snippet of dialplan how to dial if some trunk is not reachable.

Imagine, we have two SIP-trunks to dial out – [trunk1] and [trunk2]. You have to set ‘qualify=yes’ for both, otherwise this method will not work.
We’ll use the SIPPEER function with the ‘status’ argument:

; Func SIPPEER
exten => 401040,NoOp
    same => n,NoOp( [trunk1] SIPPEER info: ${SIPPEER(trunk1,status)})
    same => n,NoOp( ;===================================== )
    same => n,NoOp( [trunk2] SIPPEER info: ${SIPPEER(trunk2,status)})
    same => n,NoOp( ;===================================== )
    same => n,GotoIf($[${SIPPEER(trunk1,status)}= "OK"]?t1dial:t2)
    same => n(t1dial),Dial(SIP/trunk1/${EXTEN},5)
    same => n,Hangup
    same => n(t2),NoOp( [trunk1] is UNREACHABLE, trying [trunk2] in 1 second ... )
    same => n,Wait(1)
    same => n,GotoIf($[${SIPPEER(trunk2,status)}= "OK"]?t2dial:hang)
    same => n(t2dial),Dial(SIP/trunk2/${EXTEN},5)
    same => n,Hangup
    same => n(hang),Playback(have-a-rest)
    same => n,Hangup

Tags: asterisk, sippeer, trunk
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FreeSWITCH: listen on UDP only

April 18th, 2014

As a default behavior, FreeSWITCH SIP profiles listen both on TCP and UDP. To disable any of them, use bind-params in /conf/sip_profiles/some_profile.xml

https://wiki.freeswitch.org/wiki/Sofia.conf.xml#bind-params

Tags: freeswitch, fs, sofia, tcp, udp
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top

March 29th, 2014

You may select the columns shown by the ‘top’ command with the ‘f’ key. Just run top and press ‘f’. Columns marked with * are shown, others are not.

In some versions of ‘top’ you have to select the [un]displayed item with arrows and activate/deactivate them with ‘d’ or space.

Tags: linux, top, unix
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