net.rb

#!/usr/bin/env ruby

require 'open3'

# What's the network interface name?
def ifaces
 `iw dev`.lines.select { |l| l["Interface "] }.map { |l| l.split(/\s+/).last }
end

# First iface
def iface
  ifaces.first
end

# Is iface up?
def up? iface
  !!(`ip link show #{iface}` =~ /<.*?UP.*?>/)
end

# Force an iface up
def up! iface
  `sudo ip link set #{iface} up`
  iface
end

# Force an iface down
def down! iface
  `sudo ip link set #{iface} down`
  iface
end

# Is there a network connection?
def link? iface
  ! (`iw #{iface} link` =~ /Not connected/)
end

# Available networks, as a map of BSS->{...}
def networks
  `sudo iw wlan0 scan`.lines.reduce([nil, {}]) do |pair, line|
    bss, map = pair
    net = map[bss]
    if line =~ /^BSS (.+?) /
      # New network
      map[$1] = {}
      [$1, map]
    else
      case line
      when /^\tSSID: (.+)/
        net[:SSID] = $1
      when /^\tRSN:/
        net[:RSN] = {}
      end
      map[bss]
      pair
    end
  end
end

# Does a network require RSN?
def rsn? network
  network[:RSN]
end

# Emits wpa_supplicant config file
def supplicant_config ssid, passphrase
  Open3::popen2("wpa_passphrase #{ssid}") do |stdin, stdout, wait_thr|
    stdin.puts passphrase
    stdin.close
    stdout.read
  end
end

# Launch wpa_supplicant
def ensure_wpa_supplicant!
  if `ps aux | grep wpa_supplicant`.lines.size <= 1
    `sudo wpa_supplicant -B -D wext -i wlan0 -c /etc/wpa_supplicant.conf`
  end
end

def wpa_supplicant_config_file
  "/etc/dbus-1/system.d/"
end

def supplicate! iface, ssid, passphrase
end