1 files changed, 163 insertions, 0 deletions
diff --git a/lib/dnspython/dns/ipv6.py b/lib/dnspython/dns/ipv6.py
new file mode 100644
index 00000000000..33c6713796d
--- /dev/null
+++ b/lib/dnspython/dns/ipv6.py
@@ -0,0 +1,163 @@
+# Copyright (C) 2003-2007, 2009, 2010 Nominum, Inc.
+#
+# Permission to use, copy, modify, and distribute this software and its
+# documentation for any purpose with or without fee is hereby granted,
+# provided that the above copyright notice and this permission notice
+# appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
+# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+"""IPv6 helper functions."""
+
+import re
+
+import dns.exception
+import dns.ipv4
+
+_leading_zero = re.compile(r'0+([0-9a-f]+)')
+
+def inet_ntoa(address):
+    """Convert a network format IPv6 address into text.
+
+    @param address: the binary address
+    @type address: string
+    @rtype: string
+    @raises ValueError: the address isn't 16 bytes long
+    """
+
+    if len(address) != 16:
+        raise ValueError("IPv6 addresses are 16 bytes long")
+    hex = address.encode('hex_codec')
+    chunks = []
+    i = 0
+    l = len(hex)
+    while i < l:
+        chunk = hex[i : i + 4]
+        # strip leading zeros.  we do this with an re instead of
+        # with lstrip() because lstrip() didn't support chars until
+        # python 2.2.2
+        m = _leading_zero.match(chunk)
+        if not m is None:
+            chunk = m.group(1)
+        chunks.append(chunk)
+        i += 4
+    #
+    # Compress the longest subsequence of 0-value chunks to ::
+    #
+    best_start = 0
+    best_len = 0
+    start = -1
+    last_was_zero = False
+    for i in xrange(8):
+        if chunks[i] != '0':
+            if last_was_zero:
+                end = i
+                current_len = end - start
+                if current_len > best_len:
+                    best_start = start
+                    best_len = current_len
+                last_was_zero = False
+        elif not last_was_zero:
+            start = i
+            last_was_zero = True
+    if last_was_zero:
+        end = 8
+        current_len = end - start
+        if current_len > best_len:
+            best_start = start
+            best_len = current_len
+    if best_len > 0:
+        if best_start == 0 and \
+           (best_len == 6 or
+            best_len == 5 and chunks[5] == 'ffff'):
+            # We have an embedded IPv4 address
+            if best_len == 6:
+                prefix = '::'
+            else:
+                prefix = '::ffff:'
+            hex = prefix + dns.ipv4.inet_ntoa(address[12:])
+        else:
+            hex = ':'.join(chunks[:best_start]) + '::' + \
+                  ':'.join(chunks[best_start + best_len:])
+    else:
+        hex = ':'.join(chunks)
+    return hex
+
+_v4_ending = re.compile(r'(.*):(\d+)\.(\d+)\.(\d+)\.(\d+)$')
+_colon_colon_start = re.compile(r'::.*')
+_colon_colon_end = re.compile(r'.*::$')
+
+def inet_aton(text):
+    """Convert a text format IPv6 address into network format.
+
+    @param text: the textual address
+    @type text: string
+    @rtype: string
+    @raises dns.exception.SyntaxError: the text was not properly formatted
+    """
+
+    #
+    # Our aim here is not something fast; we just want something that works.
+    #
+
+    if text == '::':
+        text = '0::'
+    #
+    # Get rid of the icky dot-quad syntax if we have it.
+    #
+    m = _v4_ending.match(text)
+    if not m is None:
+        text = "%s:%04x:%04x" % (m.group(1),
+                                 int(m.group(2)) * 256 + int(m.group(3)),
+                                 int(m.group(4)) * 256 + int(m.group(5)))
+    #
+    # Try to turn '::<whatever>' into ':<whatever>'; if no match try to
+    # turn '<whatever>::' into '<whatever>:'
+    #
+    m = _colon_colon_start.match(text)
+    if not m is None:
+        text = text[1:]
+    else:
+        m = _colon_colon_end.match(text)
+        if not m is None:
+            text = text[:-1]
+    #
+    # Now canonicalize into 8 chunks of 4 hex digits each
+    #
+    chunks = text.split(':')
+    l = len(chunks)
+    if l > 8:
+        raise dns.exception.SyntaxError
+    seen_empty = False
+    canonical = []
+    for c in chunks:
+        if c == '':
+            if seen_empty:
+                raise dns.exception.SyntaxError
+            seen_empty = True
+            for i in xrange(0, 8 - l + 1):
+                canonical.append('0000')
+        else:
+            lc = len(c)
+            if lc > 4:
+                raise dns.exception.SyntaxError
+            if lc != 4:
+                c = ('0' * (4 - lc)) + c
+            canonical.append(c)
+    if l < 8 and not seen_empty:
+        raise dns.exception.SyntaxError
+    text = ''.join(canonical)
+
+    #
+    # Finally we can go to binary.
+    #
+    try:
+        return text.decode('hex_codec')
+    except TypeError:
+        raise dns.exception.SyntaxError