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Versions: 21
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Contents
require "ftw/namespace"
# A FTW::DNS resolver that uses Socket.gethostbyname() to resolve addresses.
class FTW::DNS::DNS
# TODO(sissel): Switch to using Resolv::DNS since it lets you (the programmer)
# choose dns configuration (servers, etc)
private
# Resolve a hostname.
#
# It will return an array of all known addresses for the host.
def resolve(hostname)
official, aliases, family, *addresses = Socket.gethostbyname(hostname)
# We ignore family, here. Ruby will return v6 *and* v4 addresses in
# the same gethostbyname() call. It is confusing.
#
# Let's just rely entirely on the length of the address string.
return addresses.collect do |address|
if address.length == 16
unpack_v6(address)
else
unpack_v4(address)
end
end
end # def resolve
# Unserialize a 4-byte ipv4 address into a human-readable a.b.c.d string
def unpack_v4(address)
return address.unpack("C4").join(".")
end # def unpack_v4
# Unserialize a 16-byte ipv6 address into a human-readable a:b:c:...:d string
def unpack_v6(address)
if address.length == 16
# Unpack 16 bit chunks, convert to hex, join with ":"
address.unpack("n8").collect { |p| p.to_s(16) } \
.join(":").sub(/(?:0:(?:0:)+)/, "::")
else
# assume ipv4
# Per the following sites, "::127.0.0.1" is valid and correct
# http://en.wikipedia.org/wiki/IPv6#IPv4-mapped_IPv6_addresses
# http://www.tcpipguide.com/free/t_IPv6IPv4AddressEmbedding.htm
"::" + unpack_v4(address)
end
end # def unpack_v6
public(:resolve)
end # class FTW::DNS::DNS
Version data entries
21 entries across 21 versions & 1 rubygems