lib: ip address presentation convert helper methods

Signed-off-by: Can Zhang <can@canx.me>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

ryu/lib/ip.py

@@ -0,0 +1,64 @@
+import struct
+
+
+def ipv4_arg_to_bin(w, x, y, z):
+    """Generate unsigned int from components of IP address
+       returns: w << 24 | x << 16 | y << 8 | z"""
+    return (w << 24) | (x << 16) | (y << 8) | z
+
+
+def ipv4_to_bin(ip):
+    '''
+        Parse an IP address and return an unsigned int.
+        The IP address is in dotted decimal notation.
+    '''
+    args = [int(arg) for arg in ip.split('.')]
+    return ipv4_arg_to_bin(*args)
+
+
+def ipv4_to_str(ip):
+    """Generate IP address string from an unsigned int.
+       ip: unsigned int of form w << 24 | x << 16 | y << 8 | z
+       returns: ip address string w.x.y.z"""
+    w = (ip >> 24) & 0xff
+    x = (ip >> 16) & 0xff
+    y = (ip >> 8) & 0xff
+    z = ip & 0xff
+    return "%i.%i.%i.%i" % (w, x, y, z)
+
+IPV6_PACK_STR = '!8H'
+
+
+def ipv6_to_arg_list(ipv6):
+    '''
+        convert ipv6 string to a list of 8 different parts
+    '''
+    args = []
+    if '::' in ipv6:
+        h, t = ipv6.split('::')
+        h_list = [int(x, 16) for x in h.split(':')]
+        t_list = [int(x, 16) for x in t.split(':')]
+        args += h_list
+        zero = [0]
+        args += ((8 - len(h_list) - len(t_list)) * zero)
+        args += t_list
+    else:
+        args = [int(x, 16) for x in ipv6.split(':')]
+
+    return args
+
+
+def ipv6_to_bin(ipv6):
+    '''
+        convert ipv6 string to binary representation
+    '''
+    args = ipv6_to_arg_list(ipv6)
+    return struct.pack(IPV6_PACK_STR, *args)
+
+
+def ipv6_to_str(bin_addr):
+    '''
+        convert binary representation to human readable string
+    '''
+    args = struct.unpack_from(IPV6_PACK_STR, bin_addr)
+    return ':'.join('%x' % x for x in args)

ryu/tests/unit/lib/test_ip.py

@@ -0,0 +1,60 @@
+import unittest
+import logging
+import struct
+import netaddr
+from struct import *
+from nose.tools import *
+from nose.plugins.skip import Skip, SkipTest
+
+from ryu.lib import ip
+
+LOG = logging.getLogger('test_ip')
+
+
+class Test_ip(unittest.TestCase):
+    '''
+        test case for ip address module
+    '''
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def test_ipv4_to_bin(self):
+        ipv4_str = '10.28.197.1'
+        val = 0x0a1cc501
+
+        res = ip.ipv4_to_bin(ipv4_str)
+        eq_(val, res)
+
+    def test_ipv4_to_str(self):
+        ipv4_bin = 0x0a1cc501
+        val = '10.28.197.1'
+
+        res = ip.ipv4_to_str(ipv4_bin)
+        eq_(val, res)
+
+    def test_ipv6_to_bin(self):
+        ipv6_str = '2013:da8:215:8f2:aa20:66ff:fe4c:9c3c'
+        val = struct.pack('!8H', 0x2013, 0xda8, 0x215, 0x8f2, 0xaa20, 0x66ff,
+                          0xfe4c, 0x9c3c)
+        res = ip.ipv6_to_bin(ipv6_str)
+        eq_(val, res)
+
+    def test_ipv6_to_bin_with_shortcut(self):
+        ipv6_str = '3f:10::1:2'
+        val = struct.pack('!8H', 0x3f, 0x10, 0, 0, 0, 0, 0x1, 0x2)
+
+        res = ip.ipv6_to_bin(ipv6_str)
+        eq_(val, res)
+
+    def test_ipv6_to_str(self):
+        ipv6_bin = struct.pack('!8H', 0x2013, 0xda8, 0x215, 0x8f2, 0xaa20,
+                               0x66ff, 0xfe4c, 0x9c3c)
+        val = '2013:da8:215:8f2:aa20:66ff:fe4c:9c3c'
+
+        res = ip.ipv6_to_str(ipv6_bin)
+        print val, res
+        eq_(val, res)