l: add autowifi service

lass/3modules/autowifi.nix

@@ -0,0 +1,111 @@
+{ config, lib, pkgs, ... }:
+with import <stockholm/lib>;
+let
+
+  cfg = config.lass.autowifi;
+
+in {
+  options.lass.autowifi = {
+    enable = mkEnableOption "automatic wifi connector";
+    knownWifisFile = mkOption {
+      type = types.str;
+      default = "/etc/wifis";
+    };
+  };
+
+  config = {
+    systemd.services.autowifi = {
+      description = "Automatic wifi connector";
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        Type = "simple";
+        Restart = "always";
+        RestartSec = "10s";
+        ExecStart = pkgs.writers.writePython3 "autowifi" {} /* python3 */ ''
+          import subprocess
+          import time
+          import urllib.request
+
+
+          def connect(ssid, psk=None):
+              subprocess.run(["${pkgs.networkmanager}/bin/nmcli", "connection", "delete", "autowifi"])
+              print("connecting to {}".format(ssid))
+              if psk is None:
+                  subprocess.run(["${pkgs.networkmanager}/bin/nmcli", "device", "wifi", "connect", ssid, "name", "autowifi"])
+              else:
+                  subprocess.run(["${pkgs.networkmanager}/bin/nmcli", "device", "wifi", "connect", ssid, "name", "autowifi", "password", psk])
+
+
+          def scan():
+              wifis_raw = subprocess.check_output(["${pkgs.networkmanager}/bin/nmcli", "-t", "device", "wifi", "list", "--rescan", "yes"])
+              wifis_list = wifis_raw.split(b'\n')
+              wifis = []
+              for line in wifis_list:
+                  ls = line.split(b':')
+                  if len(ls) == 8:
+                      wifis.append({"ssid": ls[1], "signal": int(ls[5]), "crypto": ls[7]})
+              return wifis
+
+
+          def get_known_wifis():
+              wifis_lines = []
+              with open('${cfg.knownWifisFile}') as f:
+                  wifis_lines = f.read().splitlines()
+              wifis = []
+              for line in wifis_lines:
+                  ls = line.split(':')
+                  wifis.append({"ssid": ls[0].encode(), "psk": ls[1].encode()})
+              return wifis
+
+
+          def check_internet():
+              try:
+                  beacon = urllib.request.urlopen('http://krebsco.de/secret')
+              except:  # noqa
+                  print("no internet")
+                  return False
+              if beacon.read() == b'1337\n':
+                  return True
+              print("no internet")
+              return False
+
+
+          def is_wifi_open(wifi):
+              if wifi['crypto'] == ${"b''"}:
+                  return True
+              else:
+                  return False
+
+
+          def is_wifi_seen(wifi, seen_wifis):
+              for seen_wifi in seen_wifis:
+                  if seen_wifi["ssid"] == wifi["ssid"]:
+                      return True
+              return False
+
+
+          def bloop():
+              while True:
+                  if not check_internet():
+                      wifis = scan()
+                      known_wifis = get_known_wifis()
+                      known_seen_wifis = [wifi for wifi in known_wifis if is_wifi_seen(wifi, wifis)]
+                      for wifi in known_seen_wifis:
+                          connect(wifi['ssid'], wifi['psk'])
+                          if check_internet():
+                              continue
+                      open_wifis = filter(is_wifi_open, wifis)
+                      for wifi in open_wifis:
+                          connect(wifi['ssid'])
+                          if check_internet():
+                              continue
+                  time.sleep(10)
+
+
+          bloop()
+        '';
+      };
+    };
+  };
+}
+

lass/3modules/default.nix

@@ -14,5 +14,6 @@ _:
     ./umts.nix
     ./usershadow.nix
     ./xjail.nix
+    ./autowifi.nix
   ];
 }