CODEWITHSUNDEEP
pythonipv6
Jeff M.
Jeff M.

Reputation: 71

Trying to format ipv6 string using ctypes

I am having trouble getting an ipv6 address formatting into a packed binary string. After doing some digging, it appears that socket.inet_pton(...) does not work in windows. While digging, I came across a suggestion to use ctypes and the InetPton function built into Ws2_32.dll. Below is my simple script:

import ctypes
import socket

a = ctypes.WinDLL("ws2_32.dll") 

in_addr_p = ctypes.create_string_buffer("200f::")
out_addr_p = ctypes.create_string_buffer(40)

a.inet_pton(socket.AF_INET6, in_addr_p, out_addr_p)
print "Input: {}".format(repr(in_addr_p.raw))
print "Output: {}".format(repr(out_addr_p.raw))

When I run it, I get the following:

Input: '200f::\x00'
Output: ' \x0f\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x
00\x00

I am stumped as to why it appears that "F" is the only character that makes it through the conversion process. '

Upvotes: 0

Views: 148

Answers (1)

mata
mata

Reputation: 69032

See that space at the beginning of ' \x0f...'? That's where the '20' ended up, as \x20 is rendered as a space. So your code is working just fine...

If you're using python3.3 or newer, you should consider using the ipaddress module for such operations. There should also be backports for python2.

Upvotes: 4

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