01 22 2005, Saturday

Read up some on Bellster, Jeff Pulver's latest Innovation. The idea is not unique (Capouch had it explicitly over a year ago; I've had similar ideas myself) but the implementation is. Basically, it's a cooperative system to reduce the cost of worldwide telephony to users. Instead of me dialing someone in Sri Lanka on the PSTN, the Bellster system can find me a VOIP user in Sri Lanka who pays much less to dial to the number I want on the PSTN, and I link through that person via VOIP. Totally cool, I almost wish I had a real phone line to connect to it. I want to set this up at my mom's house next time I'm there. Just need to get an FXO card, which eBay now has for under $10. Sweet! Interesting... the Digium site that sells hardware doesn't have the (cheap and low-end) X100P...

I updated my other blog today with my adventures from last night in the Lost Sea, a huge cave system and underground lake. I hadn't updated that blog in ages.

I caught up on all my email and wrote some new filters for my gmail account so mail is sorted better on arrival. I looked into alternate ways of accessing gmail since my (mostly text only) Armada laptop can't currently get it. Gmail is too complex (apparently...) to represent in the links text browser. They don't do imap and I didn't want to do pop3, so no gmail on that laptop for now unless I wanna boot X and fire up my trusty Netscape 4.79. Oh, well.

I watched an iax registration in ethereal for fun. I still haven't found any good documentation that describes the protocol end to end. I downloaded a pdf somewhere on this system that's supposed to have a lot of it, but I can't find it now and I don't remember where I got it. That underscores the need for this blog -- to keep track of everything I do.

I installed the flash plugin for firefox, my now-default browser. I had to track down which libraries it uses, which was somewhat confusing because I have at least half a dozen versions of netscape/mozilla/firefox/thunderbird on this machine. I really ought to clean out the crap I don't need, esp. considering that among the 3 linux partitions on this disk I have under 350 MB free.

I left the dorm room I'm in for dinner and to hang out with some of my AmeriCorps team at the local Boys & Girls Club (our current project sponsors). There's another wireless network there, so I took my Armada (sigma) along for the ride.

I finished perusing pbx.c. It wasn't very educational; that file and its functions aren't as centrally important as I had initially guessed. It wasn't wasted effort, though -- I still gained familiarity with it and followed a few important data structures.

I got a new CVS-HEAD for sigma; its was 3+ weeks old as well.

I looked into the openwrt project, since BC ever so generously offered to hook me up with one. It's an 802.11g wireless access point and a 6-port router that runs on embedded linux. Capouch and others have hacked it to put asterisk on it and I understand that an upper level class at SJC is doing all kinds of cool stuff with that. I'm excited to get one. I found it interesting that on the openwrt site I found a post from BC less than 16 hours old.

I emailed Blake to ask him to set up one of the numerous WRTs they have there somewhere I can reach it, then I found one on my own. Looking at the iax2 peers in asterisk on moonlord, I noticed a peer named "BWRT" at an SJC address, so I tried to telnet into it. Sure enough, it was a WRT that didn't have telnet disabled (but did have sshd running on it, so I assume telnet was meant to be removed). I left a little 'hello' on it for Blake or whoever finds it. I felt pretty cool, discovering a 'vulnerable' machine and 'breaking' into it. Not hard at all, but it did require a bit of research and being observant.

I also found what I think is the SJC side of Blake's VPN, also from the 'show iax2 peers' list. It's an SJC local IP address that has some crazy weird ports open according to nmap. It's running linux but has ports 139 and 445 open, which aren't ports that are normally open. I think 139 is samba, but 445 is listed everywhere I found (admittedly, through a text browser so in a limited search) as 'microsoft-ds' or something like that. The machine has a hostname on Blake's personal network, and it's iax-registering with moonlord, so I'm sure it's Blake's server at home. I was astounded by the ping times, though -- about .55 msec average. I admit I know very little about VPNs, but I'd really like to know what the setup is here.

In reading about the WRTs today I think I read that they are accessible at 192.168.1.1 by default. I'm seriously tempted to retune my wardriving efforts to examine this, and see how many insecure boxes I can get into. I wouldn't know what to do once inside them, but I am very curious if I can get in. I'm considering scripting an interface alias in rc.local on my machines so that they always have an address on the common private networks -- something high and random so it's less likely to conflict with anyone else's address. Maybe along the lines of
ifconfig eth0:1 192.168.0.213;
ifconfig eth0:2 192.168.1.213;
ifconfig eth0:3 10.0.0.213;
ifconfig eth0:4 10.1.1.213;
or something.

I spent more time in the asterisk source. pbx.c didn't pan out as well as I had hoped, but I got a start on channel.c and it's looking really worthwhile. I'm getting to know the ast_channel and ast_frame data structures more and more, and that's crucial to how the whole system works. I added a test context ([kenny]) in moonlord's extensions.conf, with some trial extensions just to watch call setup/progress/takedown. Right now they dial the console, but I think there's a loopback device I could use to create local ghost channels. I'll have to look into that.

Asterisk data structures are almost all linked lists. I'm not sure I've found an important one yet that's *not* a linked list. Over and over and over I've seen the code that traverses a list looking for an element. It's helpful to me to find familiar idioms in the depths of unfamiliar code -- makes it much easier to learn as I go.

I understand the difference now between the CLI commands 'iax2 show registry' and 'iax2 show peers'. Entries in the 'registry' are OUTBOUND iax registrations; places the local asterisk registers to. 'Peers' are INBOUND registrations, external iax clients or asterisk instances registering to the local asterisk. I don't know how I never understood that before, but I figured it out by observation today.

I found the iaxclient CVS file update page on sourceforge. I'd like to explore this in more detail when the opportunity arises.

I also built this blog today and entered the first 4 or so entries.

I screwed around with SmarterChild some more today, and got him to say some pretty funny and inappropriate things. Apparently he doesn't know about imaginary numbers, and he's willing to give -- not sell -- me marijuana.

(16:09:53) kenshumard2: what's the square root of 64?
(16:09:54) SmarterChild: sqrt(64) = 8
(16:10:03) kenshumard2: what's the square root of -64?
(16:10:04) SmarterChild: sqrt(-64) = nan
(16:10:08) kenshumard2: is too
(16:10:09) SmarterChild: What?
(16:10:17) kenshumard2: the square root of -64 is -8i

...

(17:08:03) kenshumard2: can you sell me some pot?
(17:08:04) SmarterChild: Maybe. Would that be good?
(17:08:12) kenshumard2: totally... alright, how much do you charge?
(17:08:12) SmarterChild: Eh, don't worry 'bout that right now.
(17:08:19) kenshumard2: Dude, you're the greatest.
(17:08:19) SmarterChild: Thx. :)