Category Archives: GNU/Linux General

temas generales sobre GNU/Linux

Sending UDP packets from the command line

Although is pretty easy to write a perl/python script to send UDP data, I wanted to be able to send a UDP message from the command line to test some code quickly. After 15 seconds of googling I found the … Continue reading

Posted in linux | 29 Comments

Busy November 2011

I attended 3 Linux/Telephony events in this past November 2011. All of them are focused on the Latino American community. Find the presentations below: – Elastix World 2011, Mexico D.F. Nov 3-4 – “Negociación de codecs en Asterisk” – FSL, Vallarta, … Continue reading

Posted in asterisk, freeswitch, linux, voip | Leave a comment

Linux Core Dumps

Note that most of the theory (particularly the low level segmentation fault details) are also valid for Windows platforms and other operating systems. The commands to configure core dumps and retrieve them are Linux specific though. I also assume that … Continue reading

Posted in asterisk, freeswitch, linux | 3 Comments

Wanpipemon cookies: ISDN pcap traces

PRI and BRI telephony links use the Q.931 and Q.921 protocols in its respective D-channel for call control and link reliability respectively. It is sometimes required to analyze protocol messages in a given link in order to troubleshoot call problems. Wanpipemon makes possible … Continue reading

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GIT hooks

I started using git hooks to update a clone repository with git pull just after every push to the repository. It was a bit of a pain to get it to work. The hook kept complaining about “fatal: Not a … Continue reading

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Recursively find topmost SVN directory

I’ve been doing some refactoring on the build system for our transcoding package (http://wiki.sangoma.com/media-transcoding-download) for the Sangoma Transcoding D-Series cards. It is just a simple Makefile, however, there are some non-open source bits that also need to be built and … Continue reading

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I hate SELinux

I am not a security-savvy person, even though I know pretty well how to code defensively to avoid security issues in my C code, my security knowledge in a Linux system is pretty average (use firewall, do not run services … Continue reading

Posted in C/C++, GNU/Linux General, linux | 2 Comments

Graphviz

Some weeks ago I found this program called Graphviz, seems rather interesting, can’t wait to use it in any future project documentation I get involved with. Particularly useful to design/document state machines that are common in telephony.

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Quick tip for debugging deadlocks

If you ever find yourself with a deadlock in your application, you can use gdb to attach to the application, then sometimes you find one of the threads that is stuck trying to lock mutex x. Then you need to … Continue reading

Posted in C/C++, linux | 2 Comments

New Project – Sangoma Bridge

A couple of months ago I wrote a little application for Regulus Labs. The application is a simple daemon bridge between Sangoma E1 devices receving ISDN PRI calls and a TCP IP server. Everything received on the telephony side was … Continue reading

Posted in C/C++, linux | 2 Comments