[tor-commits] [stem/master] Utility for validating IPv6 addresses

[atagar at torproject.org]

commit dbd6a80ffc65f8d77d6d798b49f8c899e5ef09e9
Author: Damian Johnson <atagar at torproject.org>
Date:   Wed Apr 11 20:50:08 2012 -0700

    Utility for validating IPv6 addresses
    
    Function and testing to check a string is a valid ipv6 address.
---
 stem/util/connection.py      |   40 ++++++++++++++++++++++++++++++++++++----
 test/unit/util/connection.py |   28 ++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 4 deletions(-)

diff --git a/stem/util/connection.py b/stem/util/connection.py
index 9c6ba8b..93030fc 100644
--- a/stem/util/connection.py
+++ b/stem/util/connection.py
@@ -6,22 +6,24 @@ https://gitweb.torproject.org/arm.git/blob/HEAD:/src/util/connections.py
 but for now just moving the parts we need.
 """
 
-def is_valid_ip_address(entry):
+import re
+
+def is_valid_ip_address(address):
   """
   Checks if a string is a valid IPv4 address.
   
   Arguments:
-    entry (str) - string to be checked
+    address (str) - string to be checked
   
   Returns:
     True if input is a valid IPv4 address, False otherwise.
   """
   
   # checks if theres four period separated values
-  if not entry.count(".") == 3: return False
+  if address.count(".") != 3: return False
   
   # checks that each value in the octet are decimal values between 0-255
-  for entry in entry.split("."):
+  for entry in address.split("."):
     if not entry.isdigit() or int(entry) < 0 or int(entry) > 255:
       return False
     elif entry[0] == "0" and len(entry) > 1:
@@ -29,6 +31,36 @@ def is_valid_ip_address(entry):
   
   return True
 
+def is_valid_ipv6_address(address):
+  """
+  Checks if a string is a valid IPv6 address.
+  
+  Arguments:
+    address (str) - string to be checked
+  
+  Returns:
+    True if input is a valid IPv6 address, False otherwise.
+  """
+  
+  # addresses are made up of eight colon separated groups of four hex digits
+  # with leading zeros being optional
+  # https://en.wikipedia.org/wiki/IPv6#Address_format
+  
+  colon_count = address.count(":")
+  
+  if colon_count > 7:
+    return False # too many groups
+  elif colon_count != 7 and not "::" in address:
+    return False # not enough groups and none are collapsed
+  elif address.count("::") > 1 or ":::" in address:
+    return False # multiple groupings of zeros can't be collapsed
+  
+  for entry in address.split(":"):
+    if not re.match("^[0-9a-fA-f]{0,4}$", entry):
+      return False
+  
+  return True
+
 def is_valid_port(entry, allow_zero = False):
   """
   Checks if a string or int is a valid port number.
diff --git a/test/unit/util/connection.py b/test/unit/util/connection.py
index 01d1c92..b4c7223 100644
--- a/test/unit/util/connection.py
+++ b/test/unit/util/connection.py
@@ -29,9 +29,37 @@ class TestConnection(unittest.TestCase):
     
     for address in valid_addresses:
       self.assertTrue(stem.util.connection.is_valid_ip_address(address))
+    
     for address in invalid_addresses:
       self.assertFalse(stem.util.connection.is_valid_ip_address(address))
   
+  def test_is_valid_ipv6_address(self):
+    """
+    Checks the is_valid_ipv6_address function.
+    """
+    
+    valid_addresses = (
+      "fe80:0000:0000:0000:0202:b3ff:fe1e:8329",
+      "fe80:0:0:0:202:b3ff:fe1e:8329",
+      "fe80::202:b3ff:fe1e:8329",
+      "::",
+    )
+    
+    invalid_addresses = (
+      "fe80:0000:0000:0000:0202:b3ff:fe1e:829g",
+      "fe80:0000:0000:0000:0202:b3ff:fe1e: 8329",
+      "2001:db8::aaaa::1",
+      ":::",
+      ":",
+      "",
+    )
+    
+    for address in valid_addresses:
+      self.assertTrue(stem.util.connection.is_valid_ipv6_address(address))
+    
+    for address in invalid_addresses:
+      self.assertFalse(stem.util.connection.is_valid_ipv6_address(address))
+  
   def test_is_valid_port(self):
     """
     Checks the is_valid_port function.