Under the covers
Figure 12 shows the main board of the Sirocco. You can see a C-Media audio chip and a RealTek chip, which are used for Ethernet support. The wireless chip is hidden under some shielding. The main CPU is covered by a heat sink, but Sondigo's documentation states it is a 200Mhz RealTek RTL8722 MIPS-based processor.
Figure 11: Main Board (Click to enlarge)
To see what software was running on the device, I first used a port scan. A fingerprint ID revealed that the TCP/IP stack was from a Linux 2.4 or 2.5 kernel. The scan also showed me that the standard HTTP port of 80 was open on the device. To investigate further, I decided to use my web browser. When I connected, I was greeted with the menu shown in Figure 13.
Figure 13: Access Point Wizard
I double-checked the documentation, but I could find no reference to any configuration that could be performed using a web browser. It's fairly common for these devices to have a native application for some configuration and a web interface for others, but it's almost always documented. I also found a logging feature that gave me a lot of information on the device's internal workings.
Like many embedded consumer devices, it was running Linux and using Busybox for utilities. I could see all the boot messages, which told me that there was 16 Meg of memory and that ext2 was used for the internal RAM disk. I identified two Ethernet devices and an RS-232 console. As I continued to play with the menus, I noticed something very odd that I had first taken to be an alternate configuration method. As I examined the menus closer, I saw that the options didn't make sense for a device that was designed to be a wireless client.
Figure 14 shows a screen that was more geared toward setting up an access point. As I reread the initial menu, back in Figure 13, I noticed that it also mentioned setting up "your Access Point". Strange.
Figure 14: Access Point Setup
Maybe this menu was left over from another similar device by the same OEM manufacturer. To see how far I could go, I started configuring the Sirocco as a wireless access point. I plugged my Ethernet cable back in, and I went through all the menus, defining my SSID, my DHCP parameters, my channel, and so on. When I completed the procedure, rebooted the device, I had a new useable access point on my LAN. Cool.
But would my audio capabilities still work? I went back to the Sirocco Control Panel. Everything looked "normal." When I used it, it worked as it had before. Interesting. Everything appeared to work fine, but maybe Sondigo didn't want to support this configuration or perhaps they feared that making the device do double-duty as both an access point and a wireless bridge would magnify audio buffering problems. In case this "feature" is dropped in the newer firmware releases, don't count on it or expect Sondigo to support you if you use it.
My investigating did show a couple of issues that Sondigo needs to address. First, the undocumented access point configuration could allow someone on your LAN to take over your Sirocco and reconfigure it for their purposes. No password prompts appeared when I connected. I could set one when I configured, but by default you weren't prompted for one. This wouldn't be an issue for most home users on a closed LAN, but Sondigo should still address the issue. The other issue was the GPL license. Sondigo used a lot of GPL-licensed software in their product, and I could not find an offer for the source code as required by the license. Hopefully this was an oversight that they plan to address soon.