From 7a9092247370fa6b2b76ba858063bad16d06b016 Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Fri, 13 Jun 2014 13:52:47 +0000
Subject: [PATCH] Catch various network/server errors.

---
 src/ddns/errors.py | 32 ++++++++++++++++++++++++++++++++
 src/ddns/system.py | 38 +++++++++++++++++++++++++++++++++++---
 2 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/src/ddns/errors.py b/src/ddns/errors.py
index cd935d0..f9cc3f6 100644
--- a/src/ddns/errors.py
+++ b/src/ddns/errors.py
@@ -23,6 +23,10 @@ class DDNSError(Exception):
 	pass
 
 
+class DDNSNetworkError(DDNSError):
+	pass
+
+
 class DDNSAbuseError(DDNSError):
 	"""
 		Thrown when the server reports
@@ -56,6 +60,20 @@ class DDNSConfigurationError(DDNSError):
 	pass
 
 
+class DDNSConnectionRefusedError(DDNSNetworkError):
+	"""
+		Thrown when a connection is refused.
+	"""
+	pass
+
+
+class DDNSConnectionTimeoutError(DDNSNetworkError):
+	"""
+		Thrown when a connection to a server has timed out.
+	"""
+	pass
+
+
 class DDNSHostNotFoundError(DDNSError):
 	"""
 		Thrown when a configuration entry could
@@ -72,6 +90,13 @@ class DDNSInternalServerError(DDNSError):
 	pass
 
 
+class DDNSNetworkUnreachableError(DDNSNetworkError):
+	"""
+		Thrown when a network is not reachable.
+	"""
+	pass
+
+
 class DDNSRequestError(DDNSError):
 	"""
 		Thrown when a request could
@@ -80,6 +105,13 @@ class DDNSRequestError(DDNSError):
 	pass
 
 
+class DDNSServiceUnavailableError(DDNSNetworkError):
+	"""
+		Equivalent to HTTP error code 503.
+	"""
+	pass
+
+
 class DDNSUpdateError(DDNSError):
 	"""
 		Thrown when an update could not be
diff --git a/src/ddns/system.py b/src/ddns/system.py
index 90226b3..59dc218 100644
--- a/src/ddns/system.py
+++ b/src/ddns/system.py
@@ -26,6 +26,7 @@ import urllib
 import urllib2
 
 from __version__ import CLIENT_VERSION
+from .errors import *
 from i18n import _
 
 # Initialize the logger.
@@ -61,7 +62,12 @@ class DDNSSystem(object):
 			Sends a request to an external web server
 			to determine the current default IP address.
 		"""
-		response = self.send_request("http://checkip6.dns.lightningwirelabs.com")
+		try:
+			response = self.send_request("http://checkip6.dns.lightningwirelabs.com", timeout=10)
+
+		# If the server could not be reached, we will return nothing.
+		except DDNSNetworkError:
+			return
 
 		if not response.code == 200:
 			return
@@ -79,7 +85,12 @@ class DDNSSystem(object):
 
 			XXX does not work for IPv6.
 		"""
-		response = self.send_request("http://checkip4.dns.lightningwirelabs.com")
+		try:
+			response = self.send_request("http://checkip4.dns.lightningwirelabs.com", timeout=10)
+
+		# If the server could not be reached, we will return nothing.
+		except DDNSNetworkError:
+			return
 
 		if response.code == 200:
 			match = re.search(r"Your IP address is: (\d+.\d+.\d+.\d+)", response.read())
@@ -129,7 +140,7 @@ class DDNSSystem(object):
 			logger.debug("  %s: %s" % (k, v))
 
 		try:
-			resp = urllib2.urlopen(req)
+			resp = urllib2.urlopen(req, timeout=timeout)
 
 			# Log response header.
 			logger.debug(_("Response header:"))
@@ -139,9 +150,30 @@ class DDNSSystem(object):
 			# Return the entire response object.
 			return resp
 
+		except urllib2.HTTPError, e:
+			# 503 - Service Unavailable
+			if e.code == 503:
+				raise DDNSServiceUnavailableError
+
+			# Raise all other unhandled exceptions.
+			raise
+
 		except urllib2.URLError, e:
+			if e.reason:
+				# Network Unreachable (e.g. no IPv6 access)
+				if e.reason.errno == 101:
+					raise DDNSNetworkUnreachableError
+				elif e.reason.errno == 111:
+					raise DDNSConnectionRefusedError
+
+			# Raise all other unhandled exceptions.
 			raise
 
+		except socket.timeout, e:
+			logger.debug(_("Connection timeout"))
+
+			raise DDNSConnectionTimeoutError
+
 	def _format_query_args(self, data):
 		args = []
 
-- 
2.39.2