From b0ae83b077f8d407722f1f154ba56e785c4adb3b Mon Sep 17 00:00:00 2001
From: Mike Frysinger <vapier@gentoo.org>
Date: Sun, 10 Jan 2021 23:51:43 -0500
Subject: [PATCH] google-wifi-he-dyn-dns: simple client for updating HE DNS
 settings behind Google WiFi

---
 .bin/google-wifi-he-dyn-dns | 78 +++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100755 .bin/google-wifi-he-dyn-dns

diff --git a/.bin/google-wifi-he-dyn-dns b/.bin/google-wifi-he-dyn-dns
new file mode 100755
index 0000000..df6212c
--- /dev/null
+++ b/.bin/google-wifi-he-dyn-dns
@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+
+"""Update HS DNS settings behind Google WiFi systems."""
+
+import argparse
+import json
+import urllib.request
+import urllib.parse
+import sys
+
+import dns.resolver
+
+
+WIFI_STATUS_URI = 'http://192.168.86.1/api/v1/status'
+
+
+def get_wan_ip():
+    with urllib.request.urlopen(WIFI_STATUS_URI) as req:
+        data = req.read()
+    status = json.loads(data)
+    return status['wan']['localIpAddress']
+
+
+def update_ip(hostname, password, ip=None):
+    """Update HE DNS with new settings."""
+    params = {
+        'hostname': hostname,
+        'password': password,
+    }
+    if ip:
+        params['myip'] = ip
+    body = urllib.parse.urlencode(params).encode()
+
+    url = 'https://dyn.dns.he.net/nic/update'
+    req = urllib.request.Request(url, body)
+
+    with urllib.request.urlopen(req) as response:
+        return response.read()
+
+
+def get_parser():
+    """Get CLI parser."""
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--hostname', required=True)
+    parser.add_argument('-p', '--password', '--key', required=True)
+    parser.add_argument('-a', '--address', '--ip')
+    parser.add_argument('-q', '--quiet', action='store_true')
+    return parser
+
+
+def main(argv):
+    """The main entry point for scripts."""
+    parser = get_parser()
+    opts = parser.parse_args(argv)
+
+    if opts.quiet:
+        p = lambda *args: None
+    else:
+        p = print
+
+    curr_ip = get_wan_ip()
+    p('Current IP', curr_ip)
+
+    p('Looking up', opts.hostname, '...')
+    answers = dns.resolver.resolve(opts.hostname, 'A')
+    for msg in answers:
+        p('Current DNS', msg.to_text())
+        if curr_ip != msg.to_text():
+            p('Updating IP')
+            resp = update_ip(opts.hostname, opts.password, opts.address)
+            p(resp)
+        else:
+            p('Up-to-date!')
+        break
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv[1:]))
-- 
2.39.5