i'm an idiot. i spent like 15 minutes debugging this.

utils/he_ipv6/tunnelbroker.py

@@ -1,3 +1,5 @@
+import datetime
+import json
 import logging
 import os
 import socket
@@ -14,6 +16,7 @@ class TunnelBroker(object):
     url_ip = 'https://ipv4.clientinfo.square-r00t.net/'
     params_ip = {'raw': '1'}
     url_api = 'https://ipv4.tunnelbroker.net/nic/update'
+    ip_cache = '~/.cache/he_tunnelbroker.my_ip.json'
 
     def __init__(self, conf_xml, tun_id = None, wan_ip = True, update = True, *args, **kwargs):
         self.conf_file = os.path.abspath(os.path.expanduser(conf_xml))
@@ -26,11 +29,18 @@ class TunnelBroker(object):
             self.tun = self._conf.tunnels[tun_id]
         self.iface_name = 'he-{0}'.format(self.tun.id)
         self.wan = wan_ip
+        self.needs_update = False
         self.force_update = update
+        self.ip_cache = os.path.abspath(os.path.expanduser(self.ip_cache))
+        self.cached_ips = []
         self.my_ip = None
         self.iface_idx = None
 
     def _get_my_ip(self):
+        if os.path.isfile(self.ip_cache):
+            with open(self.ip_cache, 'r') as fh:
+                self.cached_ips = [(datetime.datetime.fromtimestamp(i[0]),
+                                    config.IP4(i[1], 32)) for i in json.loads(fh.read())]
         if self.wan:
             logger.debug('WAN IP tunneling enabled; fetching WAN IP.')
             req = requests.get(self.url_ip, params = self.params_ip)
@@ -49,12 +59,19 @@ class TunnelBroker(object):
             self.my_ip = config.IP4(_defrt[0]['attrs']['RTA_PREFSRC'], 32)
             ipr.close()
             logger.debug('Set my_ip to {0}.'.format(self.my_ip.str))
+        chk_tuple = (datetime.datetime.utcnow(), self.my_ip)
+        if self.my_ip.str != self.cached_ips[-1][1].str:
+            self.needs_update = True
+        if self.needs_update:
+            self.cached_ips.append(chk_tuple)
+            with open(self.ip_cache, 'w') as fh:
+                fh.write(json.dumps([(i[0].timestamp(), i[1].str) for i in self.cached_ips], indent = 4))
         return(None)
 
     def start(self):
-        if self.force_update:
-            logger.debug('IP update forced; updating.')
-            self._get_my_ip()
+        self._get_my_ip()
+        if any((self.force_update, self.needs_update)):
+            logger.debug('IP update forced or needed; updating.')
             self.update()
         logger.debug('Attempting to clean up any pre-existing config')
         try:
@@ -184,8 +201,9 @@ class TunnelBroker(object):
         self.tun.radvd.svc.stop()
         return(None)
 
-    def update(self, oneshot = False):
-        self._get_my_ip()
+    def update(self):
+        if not self.my_ip:
+            self._get_my_ip()
         auth_handler = requests.auth.HTTPBasicAuth(self.tun.creds.user, self.tun.creds.key)
         logger.debug('Set auth handler.')
         logger.debug('Requesting IP update at provider.')