[Python-Dev] IPv6 hostname resolution using socket.getaddrinfo() (original) (raw)

O.R.Senthil Kumaran orsenthil at gmail.com
Wed Sep 19 03:27:40 CEST 2007

On python2.4.1

>>> socket.getaddrinfo('www.python.org', None, socket.AFINET, socket.SOCKDGRAM, socket.IPPROTOIP, socket.AICANONNAME) [(2, 2, 17, 'dinsdale.python.org', ('82.94.237.218', 0))] >>> Blinston.

Thanks a lot, Blinston. That helped. I just have to take care of socket.AF_INET6 flag for IPv6 now.

socket.getaddrinfo('localhost', None, socket.AFINET6, socket.SOCKDGRAM, socket.IPPROTOIP, socket.AICANONNAME) [(10, 2, 17, 'localhost', ('fe80::219:5bff:fefd:6270', 0, 0, 0))]

Shall do a little more research on flags and see if documentation needs any update. Because current one speaks only about AI_CANONNAME being set.

Thank you. :) Senthil

-----Original Message----- From: python-dev-bounces+blinstonfernandes=dell.com at python.org [mailto:python-dev-bounces+blinstonfernandes=dell.com at python.org] On Behalf Of O.R.Senthil Kumaran Sent: Monday, September 17, 2007 10:08 PM To: python-dev at python.org Subject: [Python-Dev] IPv6 hostname resolution using socket.getaddrinfo() To get the hostname, I can use socket.gethostbyname() but that has an inherent limitation wherein does it not support IPv6 name resolution, and getaddrinfo() should be used instead. Looking up the socket.getaddrinfo() documentation, I come to know that The getaddrinfo() function returns a list of 5-tuples with the following structure: (family, socktype, proto, canonname, sockaddr) family, socktype, proto are all integer and are meant to be passed to the socket() function. canonname is a string representing the canonical name of the host. It can be a numeric IPv4/v6 address when AICANONNAME is specified for a numeric host. With this information, if I try something like this: >>> for res in socket.getaddrinfo('goofy.goofy.com', None, socket.AICANONNAME): print res (2, 1, 6, '', ('10.98.1.6', 0)) (2, 2, 17, '', ('10.98.1.6', 0)) (2, 3, 0, '', ('10.98.1.6', 0)) In the output, I see the cannoname to be always blank ''. I am not getting the IPv4 or IPv6 address as a result of using getaddrinfo(). Am I making any mistake? What i am trying is a replacement function for socket.gethostbyname(hostname) which will work for both IPv4 and IPv6 (and make changes in urllib2 to support that) # return hostbyname for either IPv4 or IPv6 address. Common function. def ipv6gethostbyname(hostname): for res in socket.getaddrinfo(hostname,None, socket.AICANONNAME): fa, socktype, proto, canonname, sa = res return cannoname The above function does not seem to work. It returns blank value only. Any help/ pointers? -- O.R.Senthil Kumaran http://uthcode.sarovar.org

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-- O.R.Senthil Kumaran http://uthcode.sarovar.org

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