UPnP is a set of protocols that allow the automatic configuration of devices. One of those protocols, the Internet Gateway Device (IGD) protocol, allows software to configure routers for NAT traversal without user-intervention. In other words, with UPnP/IGD, the long and error-prone manual configuration for port-forwarding can be done automatically.
When tasks are done automatically, they are less visible to the user, and users are not comfortable that they are in charge of the process.
For the case of UPnP/IGD, we look into the open-source (LGPL) GUPnP library and the companion tool gupnp-universal-cp. You can install these from source (pick the packages gssdp, gupnp, gupnp-tools, and install in this order), or just install the package gupnp-tools from your package manager (for Debian and Ubuntu, these packages reside in Debian unstable).
Once you have installed the tool, you can start it from Application→Programming→UPnP Universal Control Point. This tool can be used for all things UPnP, however we focus on IGD here.
Once we start the UPnP Universal Control Point, we get the above screen. The tool sends discovery requests to the local network for UPnP-capable devices, and automatically the list gets populated. In the screenshot you can see that a router has been detected, and general information is shown.
If your router does not appear in the list and you are sure that UPnP is enabled on the device, then you might have hit on a known bug, Bug 1078 - Some devices may not work due to User-Agent field in requests. In this case, you need to make a minor edit in the source code and recompile.
You can easily distinguish the functions that allow to perform port-forwarding. The one we have highlighted can be used to list the details of the currently active port-forwarding rulers. We right-click and select Invoke, which leads us to...
We just pressed the Invoke button, and since there was a rule with Index 0, the details get filled in for us. Here we can see that Skype has opened a port-forwarding rule for us; when someone from the Internet is connected to port 18210 of this router, the network connection is mapped to the local system with IP address 192.168.1.67. In the mapping description it shows that Skype was the program that set this rule.
You would normally increase the Mapping Index and click on Invoke, in order to see any additional port mappings. Skype generally opens a few more ports, so there is more to see.
For all the shortcommings, UPnP/IGD is an important network configuration protocol. Due to the lack of an open-source library, applications had to implement UPnP support from scratch. Now with GUPnP, it is much easier to write UPnP-enabled applications.
UPnP/IGD is very important for applications such as Ekiga, Pidgin (file transfers!), Empathy, XChat (for DCC). This has to be done in order to raise the bar in terms of connectivity, and so that it Just works.
I see two issues that plague FLOSS VoIP apps and do not allow their widest adoption. The first VoIP app that gets these, should get fame and glory.
First, the majority of users are broadband users, with a router that protects the inside systems. It is not possible for an outsider to initiate a network connection to a system inside the LAN. If both users that try to communicate have this typical network configuration, then the current tools say something like «You have a symmetric NAT, and at the moment the way to fix this is to either put your computer in the DMZ or enable manually port-forwarding for specific ports.» Ekiga discusses this issue at Ekiga behind a NAT router and directs the affected users (when using the program) to that page. Twinkle (QT-based SIP-phone) shows you a dialog box with the exact ports to enable for port-forwarding on your router.
The issue of a symmetric NAT can be solved in most of the cases by using the UPnP protocol. If the router supports UPnP (most do by default), then the VoIP app can enable the port-forwarding by itself, transparently from the user, and it will just work.
Until recently there was no good UPnP library, which was probably the reason for the lack of support. However, this changed with GUPnP.
The bug report to add (G)UPnP support to Ekiga is Bug 337166 – UPnP for firewall/NAT penetration.
The other issue is the difficulty in configuring your third-party VoIP SIP account, that allows you to make inexpensive voice conversations to telephones and mobiles. The reason why it is difficult is because the user has to figure out the SIP server and other configuration details. The terminology is confusing, registrar, domain, etc.
Ekiga has good support in configuring Diamondcard. The user is presented with a Wizard when configuring for the first time Ekiga.
What needs to be done is to put together the details for each provider and maintain a list at ekiga.com. The client would have a copy of the list, and allow on-demand updates. The bug report, Bug 547215 – Ekiga should know all SIP/VoIP providers, allow easy account addition.
Update 11Aug08: Wiki page with PC-to-phone providers and their details.
I attended FOSDEM '08 which took place on the 23rd and 24th of February in Brussels.
Compared to other events, FOSDEM is a big event with over 4000 (?) participants and over 200 lectures (from lightning talks to keynotes). It occupied three buildings at a local university. Many sessions were taking place at the same time and you had to switch from one room to another. What follows is what I remember from the talks. Remember, people recollect <8% of the material they hear in a talk.
The first keynote was by Robin Rowe and Gabrielle Pantera, on using Linux in the motion picture industry. They showed a huge list of movies that were created using Linux farms. The first big item in the list was the movie Titanic (1997). The list stopped at around 2005 and the reason was that since then any significant movie that employs digital editing or 3D animation is created on Linux systems. They showed trailers from popular movies and explained how technology advanced to create realistic scenes. Part of being realistic, a generated scene may need to be blurred so that it does not look too crisp.
Next, Robert Watson gave a keynote on FreeBSD and the development community. He explained lots of things from the community that someone who is not using the distribution does not know about. FreeBSD apparently has a close-knit community, with people having specific roles. To become a developer, you go through a structured mentoring process which is great. I did not see such structured approach described in other open-source projects.
Pieter Hintjens, the former president of the FFII, talked about software patents. Software patents are bad because they describe ideas and not some concrete invention. This has been the view so that the target of the FFII effort fits on software patents. However, Pieter thinks that patents in general are bad, and it would be good to push this idea.
CMake is a build system, similar to what one gets with automake/autoconf/makefile. I have not seen this project before, and from what I saw, they look quite ambitious. Apparently it is very easy to get your compilation results on the web when you use CMake. In order to make their project more visible, they should make effort on migration of existing projects to using CMake. I did not see yet a major open-source package being developed with CMake, apart from CMake itself.
Richard Hughes talked about PackageKit, a layer that removes the complexity of packaging systems. You have GNOME and your distribution is either Debian, Ubuntu, Fedora or something else. PackageKit allows to have a common interface, and simplifies the workflow of managing the installation of packages and the updates.
In the Virtualisation tracks, two talks were really amazing. Xen and VirtualBox. Virtualisation is hot property and both companies were bought recently by Citrix and Sun Microsystems respectively. Xen is a Type 1 (native, bare metal) hypervisor while VirtualBox is a Type 2 (hosted) hypervisor. You would typically use Xen if you want to supply different services on a fast server. VirtualBox is amazingly good when you want to have a desktop running on your computer.
Ian Pratt (Xen) explained well the advantages of using a hypervisor, going into many details. For example, if you have a service that is single-threaded, then it makes sense to use Xen and install it on a dual-core system. Then, you can install some other services on the same system, increasing the utilisation of your investment.
Achim Hasenmueller gave an amazing talk. He started with a joke; I have recently been demoted. From CEO to head of virtualisation department (name?) at Sun Microsystems. He walked through the audience on the steps of his company. The first virtualisation product of his company was sold to Connectix, which then was sold to Microsoft as VirtualPC. Around 2005, he started a new company, Innotek and the product VirtualBox. The first customers were government agencies in Germany and only recently (2007) they started selling to end-users.
Virtualisation is quite complex, and it becomes more complex if your offering is cross platform. They manage the complexity by making VirtualBox modular.
VirtualBox comes in two versions; an open-source version and a binary edition. The difference is that with the binary edition you get USB support and you can use RDP to access the host. If you installed VirtualBox from the repository of your distribution, there is no USB support. He did not commit whether the USB/RDP support would make it to the open-source version, though it might happen since Sun Microsystems bought the company. I think that if enough people request it, then it might happen.
VirtualBox uses QT 3.3 as the cross platform toolkit, and there is a plan to migrate to QT 4.0. GTK+ was considered, though it was not chosen because it does not provide yet good support in Win32 (applications do not look very native on Windows). wxWidgets were considered as well, but also rejected. Apparently, moving from QT 3.3 to QT 4.0 is a lot of effort.
Zeeshan Ali demonstrated GUPnP, a library that allows applications to use the UPnP (Universal Plug n Play) protocol. This protocol is used when your computer tells your ADSL model to open a port so that an external computer can communicate directly with you (bypassing firewall/NAT). UPnP can also be used to access the content of your media station. The gupnp library comes with two interesting tools; gupnp-universal-cp and gupnp-network-light. The first is a browser of UPnP devices; it can show you what devices are available, what functionality they export, and you can control said devices. For example, you can use GUPnP to open a port on your router; when someone connects from the Internet to port 22 on your modem, he is redirected to your server, at port 22.
You can also use the same tool to figure out what port mapping took place already on your modem.
The demo with the network light is that you run the browser on one computer and the network light on another, both on the local LAN (this thing works only on the local LAN). Then, you can use the browser to switch on/off the light using the UPnP protocol.
Dimitris Glezos gave a talk on transifex, the translation management framework that is currently used in Fedora. Translating software is a tedious task, and currently translators spent time on management tasks that have little to do with translation. We see several people dropping from translations due to this. Transifex is an evolving platform to make the work of the translator easier.
Dimitris talked about a command-line version of transifex coming out soon. Apparently, you can use this tool to grab the Greek translation of package gedit, branch HEAD. Do the translation and upload back the file.
What I would like to see here is a tool that you can instruct it to grab all PO files from a collection of projects (such as GNOME 2.22, UI Translations), and then you translate with your scripts/tools/etc. Then, you can use transifex to upload all those files using your SVN account.
The workflow would be something like
$ tfx --project=gnome-2.22 --collection=gnome-desktop --action=get
Reading from http://svn.gnome.org/svn/damned-lies/trunk/releases.xml.in... done.
Getting alacarte... done.
Getting bug-buddy... done.
Completed in 4:11s.
Now we translate any of the files we downloaded, and we push back upstream (of course, only those files that were changed).
$ tfx --project=gnome-2.22 --collection=gnome-desktop --user=simos --action=send
Reading local files...
Found 6 changed files.
Uploading alacarte... done.
Completed uploading translation files to gnome-2.22.
Berend Cornelius talked about creating OpenOffice.org Wizards. You get such wizards when you click on File/Wizards..., and you can use them to fill in entries in a template document (such as your name, address, etc in a letter), or use to install the spellchecker files. Actually, one of the most common uses is to get those spellchecker files installed.
A wizard is actually an OpenOffice.org extension; once you write it and install it (Tools/Extensions...), you can have it appear as a button on a toolbar or a menu item among other menus.
You write wizards in C++, and one would normally work on an existing wizard as base for new ones.
When people type in a word-processor, they typically abuse it (that's my statement, not Berend's) by omitting the use of styles and formatting. This makes documents difficult to maintain. Having a wizard teach a new user how to write a structured document would be a good idea.
Perry Ismangil talked about pjsip, the portable open-source SIP and media stack. This means that you can have Internet telephony on different devices. Considering that Internet Telephony is a commodity, this is very cool. He demonstrated pjsip running two small devices, a Nintendo DS and an iPhone. Apparently pjsip can go on your OpenWRT router as well, giving you many more exciting opportunities.
Clutter is a library to create fast animations and other effects on the GNOME desktop. It uses hardware acceleration to make up for the speed. You don't need to learn OpenGL stuff; Clutter is there to provide the glue.
Gutsy has Clutter 0.4.0 in the repositories and the latest version is 0.6.0. To try out, you need at least the clutter tarball from the Clutter website. To start programming for your desktop, you need to try some of the bindings packages.
I had the chance to spend time with the DejaVu guys (Hi Denis, Ben!). Also met up with Alexios, Dimitris x2, Serafeim, Markos and others from the Greek mission.
Overall, FOSDEM is a cool event. In two days there is so much material and interesting talks. It's a recommended technical event.