add simple view

app/lib/anonymize_ip.py

@@ -0,0 +1,105 @@
+# https://raw.githubusercontent.com/samuelmeuli/anonymize-ip/7f4faedf64643bd3de3607ab8905c1b1a3f8841a/anonymizeip/anonymize_ip.py
+
+from ipaddress import ip_address
+
+
+def anonymize_ip(
+    address,
+    ipv4_mask="255.255.255.0",
+    ipv6_mask="ffff:ffff:ffff:ffff:0000:0000:0000:0000"
+):
+    """
+    Anonymize the provided IPv4 or IPv6 address by setting parts of the
+    address to 0
+
+    :param str|int address: IP address to be anonymized
+    :param str ipv4_mask: Mask that defines which parts of an IPv4 address are
+    set to 0 (default: "255.255.255.0")
+    :param str ipv6_mask: Mask that defines which parts of an IPv6 address are
+    set to 0 (default: "ffff:ffff:ffff:ffff:0000:0000:0000:0000")
+    :return: Anonymized IP address
+    :rtype: str
+    """
+
+    # IP address to be anonymized
+    address_packed = ip_address(address).packed
+    address_len = len(address_packed)
+
+    if address_len == 4:
+        # IPv4
+        ipv4_mask_packed = ip_address(ipv4_mask).packed
+        __validate_ipv4_mask(ipv4_mask_packed)
+        return __apply_mask(address_packed, ipv4_mask_packed, 4)
+    elif address_len == 16:
+        # IPv6
+        ipv6_mask_packed = ip_address(ipv6_mask).packed
+        __validate_ipv6_mask(ipv6_mask_packed)
+        return __apply_mask(address_packed, ipv6_mask_packed, 16)
+    else:
+        # Invalid address
+        raise ValueError("Address does not consist of 4 (IPv4) or 16 (IPv6) "
+                         "octets")
+
+
+def __apply_mask(address_packed, mask_packed, nr_bytes):
+    """
+    Perform a bitwise AND operation on all corresponding bytes between the
+    mask and the provided address. Mask parts set to 0 will become 0 in the
+    anonymized IP address as well
+
+    :param bytes address_packed: Binary representation of the IP address to
+    be anonymized
+    :param bytes mask_packed: Binary representation of the corresponding IP
+    address mask
+    :param int nr_bytes: Number of bytes in the address (4 for IPv4, 16 for
+    IPv6)
+    :return: Anonymized IP address
+    :rtype: str
+    """
+
+    anon_packed = bytearray()
+    for i in range(0, nr_bytes):
+        anon_packed.append(mask_packed[i] & address_packed[i])
+    return str(ip_address(bytes(anon_packed)))
+
+
+def __validate_ipv4_mask(mask_packed):
+    # Test that mask only contains valid numbers
+    for byte in mask_packed:
+        if byte != 0 and byte != 255:
+            raise ValueError("ipv4_mask must only contain numbers 0 or 255")
+
+    # Test that IP address does not get anonymized completely
+    if mask_packed == b'\x00\x00\x00\x00':
+        raise ValueError("ipv4_mask cannot be set to \"0.0.0.0\" (all "
+                         "anonymized addresses will be 0.0.0.0)")
+
+    # Test that IP address is changed by anonymization
+    if mask_packed == b'\xff\xff\xff\xff':
+        raise ValueError("ipv4_mask cannot be set to \"255.255.255.255\" "
+                         "(addresses will not be anonymized)")
+
+
+def __validate_ipv6_mask(mask_packed):
+    # Test that mask only contains valid numbers
+    for byte in mask_packed:
+        if byte != 0 and byte != 255:
+            raise ValueError("ipv6_mask must only contain numbers 0 or ffff")
+
+    # Test that IP address does not get anonymized completely
+    if (
+        mask_packed ==
+        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
+    ):
+        raise ValueError("ipv6_mask cannot be set to "
+                         "\"0000:0000:0000:0000:0000:0000:0000:0000\" (all "
+                         "anonymized addresses will be 0.0.0.0)")
+
+    # Test that IP address is changed by anonymization
+    if (
+        mask_packed ==
+        b'\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff'
+    ):
+        raise ValueError("ipv6_mask cannot be set to "
+                         "\"ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff\" "
+                         "(addresses will not be anonymized)")