Connecting to availible hotspots and feeding to ethernet?

~slice · 2013-12-13 17:39:01

Not looking for a full walk through, just need someone to point me in the right direction and maybe a few keywords.

So me and my girlfriend both have hotspots and no cable/modem service at my place. So my goal is to take my Raspberry Pi with Arch installed add a usb Wi-Fi and have it pick up the hotspots and feed it out the Ethernet to my router.

Key features that I am looking for:
- Ability to prioritize which hotspot to pick up (I have unlimited data)
- Ability to block/enable ports dependent on what hotspot is connected (I don’t want my usenet downloading on her hotspot)

Again any input towards programs to use or files and keywords for my research is greatly appreciated.

clfarron4 · 2013-12-13 20:18:07

I've never thought about the Raspberry Pi, but isn't based on the ARM architecture? If so, you might want to ask on the ArchLinux ARM forums.

nomorewindows · 2013-12-13 20:55:47

You would just read up on the internet sharing wiki. It should be about the same for the raspberry pi as the regular arch.

Xyne · 2013-12-13 23:05:12

Is this helpful?

~slice · 2013-12-13 23:56:23

All of the config stuff is generally the same on the arm architecture. I came here for the Networking Gurus. Thanks nomorewindows I didn't even know that existed. Good stuff Xyne, I like pictures. I'll go through all of that and see what I can setup. Any other input is appreciated.

mrinx · 2013-12-14 02:20:03

As nomorewindows mentioned, internet sharing wiki page is a good place to start.

You can write your own service file for the raspbery, somewhere there will be

ExecStart=/usr/bin/ip link set eth0 up
ExecStart=/usr/bin/ip addr add 192.168.7.1/24 dev eth0
ExecStart=/usr/bin/sysctl net.ipv4.ip_forward=1
ExecStart=/usr/bin/iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

ExecStop=...
Try to write the ExecStops by yourself.
Then the easiest way is to set static IP for WAN port on your router, IP 192.168.7.2, mask 255.255.255.0, gateway 192.168.7.1 (it would be wasting of resources to run DHCP server just for one client).

The solution above doesn't solve your key features though, but I think it's a good start.

How do you want to prioritize what hotspot to pick up, do you have some algorithm for it on your mind?
Blocking of ports is easy with iptables, you just have to find out how to determine what hotspot you are connected to. I would say it's related to prioritizing your hotspots, as you would probably like to change it anytime when the Pi change the AP that it is connected to.

nomorewindows · 2013-12-15 14:52:53

mrinx wrote:

As nomorewindows mentioned, internet sharing wiki page is a good place to start.
You can write your own service file for the raspbery, somewhere there will be
ExecStart=/usr/bin/ip link set eth0 up
ExecStart=/usr/bin/ip addr add 192.168.7.1/24 dev eth0
ExecStart=/usr/bin/sysctl net.ipv4.ip_forward=1
ExecStart=/usr/bin/iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE
ExecStop=...
Try to write the ExecStops by yourself.
Then the easiest way is to set static IP for WAN port on your router, IP 192.168.7.2, mask 255.255.255.0, gateway 192.168.7.1 (it would be wasting of resources to run DHCP server just for one client).
The solution above doesn't solve your key features though, but I think it's a good start.
How do you want to prioritize what hotspot to pick up, do you have some algorithm for it on your mind?
Blocking of ports is easy with iptables, you just have to find out how to determine what hotspot you are connected to. I would say it's related to prioritizing your hotspots, as you would probably like to change it anytime when the Pi change the AP that it is connected to.

Just write a netctl script for this purpose, and save your iptables for later, just starting iptables when you need it.

mrinx · 2013-12-15 14:56:05

I believe he can't get the internet through without iptables.

nomorewindows · 2013-12-15 15:38:06

mrinx wrote:

I believe he can't get the internet through without iptables.

He doesn't need iptables masquerade until he is routing traffic through the raspberry pi for other clients. There are still default iptables when not in use.

mrinx · 2013-12-15 17:46:04

nomorewindows wrote:

until he is routing traffic through the raspberry pi for other clients.

But that is exactly what he wants to do.

nomorewindows · 2013-12-15 23:27:39

mrinx wrote:

nomorewindows wrote:
until he is routing traffic through the raspberry pi for other clients.
But that is exactly what he wants to do.

Then you just leave iptables enabled through systemd, given that he has saved his iptables.rules Also enable the netctl profile so that it assigns itself the same IP configuration each time. No problem there, just much more standard to do it this way. Don't forget to set the ipv4.forwarding option in /etc/sysctl/sysctl.conf.

Last edited by nomorewindows (2013-12-15 23:33:11)

Arch Linux

#1 2013-12-13 17:39:01

Connecting to availible hotspots and feeding to ethernet?

#2 2013-12-13 20:18:07

Re: Connecting to availible hotspots and feeding to ethernet?

#3 2013-12-13 20:55:47

Re: Connecting to availible hotspots and feeding to ethernet?

#4 2013-12-13 23:05:12

Re: Connecting to availible hotspots and feeding to ethernet?

#5 2013-12-13 23:56:23

Re: Connecting to availible hotspots and feeding to ethernet?

#6 2013-12-14 02:20:03

Re: Connecting to availible hotspots and feeding to ethernet?

#7 2013-12-15 14:52:53

Re: Connecting to availible hotspots and feeding to ethernet?

#8 2013-12-15 14:56:05

Re: Connecting to availible hotspots and feeding to ethernet?

#9 2013-12-15 15:38:06

Re: Connecting to availible hotspots and feeding to ethernet?

#10 2013-12-15 17:46:04

Re: Connecting to availible hotspots and feeding to ethernet?

#11 2013-12-15 23:27:39

Re: Connecting to availible hotspots and feeding to ethernet?

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