Object
Resolv::DNS is a DNS stub resolver.
Information taken from the following places:
STD0013
RFC 1035
etc.
Creates a new DNS resolver.
config_info can be:
nil |
Uses /etc/resolv.conf. |
String |
Path to a file using /etc/resolv.conf’s format. |
Hash |
Must contain :nameserver, :search and :ndots keys. |
:nameserver_port can be used to specify port number of nameserver address.
The value of :nameserver should be an address string or an array of address strings.
:nameserver => ‘8.8.8.8’
:nameserver => [‘8.8.8.8’, ‘8.8.4.4’]
The value of :nameserver_port should be an array of pair of nameserver address and port number.
:nameserver_port => [[‘8.8.8.8’, 53], [‘8.8.4.4’, 53]]
Example:
Resolv::DNS.new(:nameserver => ['210.251.121.21'], :search => ['ruby-lang.org'], :ndots => 1)
# File resolv.rb, line 333
def initialize(config_info=nil)
@mutex = Mutex.new
@config = Config.new(config_info)
@initialized = nil
end
Creates a new DNS resolver. See Resolv::DNS.new for argument details.
Yields the created DNS resolver to the block, if given, otherwise returns it.
# File resolv.rb, line 298
def self.open(*args)
dns = new(*args)
return dns unless block_given?
begin
yield dns
ensure
dns.close
end
end
Closes the DNS resolver.
# File resolv.rb, line 352
def close
@mutex.synchronize {
if @initialized
@initialized = false
end
}
end
Iterates over all IP addresses for name retrieved from the DNS resolver.
name can be a Resolv::DNS::Name or a String. Retrieved addresses will be a Resolv::IPv4 or Resolv::IPv6
# File resolv.rb, line 390
def each_address(name)
each_resource(name, Resource::IN::A) {|resource| yield resource.address}
if use_ipv6?
each_resource(name, Resource::IN::AAAA) {|resource| yield resource.address}
end
end
Iterates over all hostnames for address retrieved from the DNS resolver.
address must be a Resolv::IPv4, Resolv::IPv6 or a String. Retrieved names will be Resolv::DNS::Name instances.
# File resolv.rb, line 437
def each_name(address)
case address
when Name
ptr = address
when IPv4::Regex
ptr = IPv4.create(address).to_name
when IPv6::Regex
ptr = IPv6.create(address).to_name
else
raise ResolvError.new("cannot interpret as address: #{address}")
end
each_resource(ptr, Resource::IN::PTR) {|resource| yield resource.name}
end
Iterates over all typeclass DNS resources for name. See getresource for argument details.
# File resolv.rb, line 493
def each_resource(name, typeclass, &proc)
lazy_initialize
requester = make_requester
senders = {}
begin
@config.resolv(name) {|candidate, tout, nameserver, port|
msg = Message.new
msg.rd = 1
msg.add_question(candidate, typeclass)
unless sender = senders[[candidate, nameserver, port]]
sender = senders[[candidate, nameserver, port]] =
requester.sender(msg, candidate, nameserver, port)
end
reply, reply_name = requester.request(sender, tout)
case reply.rcode
when RCode::NoError
extract_resources(reply, reply_name, typeclass, &proc)
return
when RCode::NXDomain
raise Config::NXDomain.new(reply_name.to_s)
else
raise Config::OtherResolvError.new(reply_name.to_s)
end
}
ensure
requester.close
end
end
Gets the IP address of name from the DNS resolver.
name can be a Resolv::DNS::Name or a String. Retrieved address will be a Resolv::IPv4 or Resolv::IPv6
# File resolv.rb, line 366
def getaddress(name)
each_address(name) {|address| return address}
raise ResolvError.new("DNS result has no information for #{name}")
end
Gets all IP addresses for name from the DNS resolver.
name can be a Resolv::DNS::Name or a String. Retrieved addresses will be a Resolv::IPv4 or Resolv::IPv6
# File resolv.rb, line 377
def getaddresses(name)
ret = []
each_address(name) {|address| ret << address}
return ret
end
Gets the hostname for address from the DNS resolver.
address must be a Resolv::IPv4, Resolv::IPv6 or a String. Retrieved name will be a Resolv::DNS::Name.
# File resolv.rb, line 413
def getname(address)
each_name(address) {|name| return name}
raise ResolvError.new("DNS result has no information for #{address}")
end
Gets all hostnames for address from the DNS resolver.
address must be a Resolv::IPv4, Resolv::IPv6 or a String. Retrieved names will be Resolv::DNS::Name instances.
# File resolv.rb, line 424
def getnames(address)
ret = []
each_name(address) {|name| ret << name}
return ret
end
Look up the typeclass DNS resource of name.
name must be a Resolv::DNS::Name or a String.
typeclass should be one of the following:
Resolv::DNS::Resource::IN::ANY
Resolv::DNS::Resource::IN::CNAME
Resolv::DNS::Resource::IN::HINFO
Resolv::DNS::Resource::IN::MINFO
Resolv::DNS::Resource::IN::MX
Resolv::DNS::Resource::IN::NS
Resolv::DNS::Resource::IN::PTR
Resolv::DNS::Resource::IN::SOA
Resolv::DNS::Resource::IN::TXT
Returned resource is represented as a Resolv::DNS::Resource instance, i.e. Resolv::DNS::Resource::IN::A.
# File resolv.rb, line 474
def getresource(name, typeclass)
each_resource(name, typeclass) {|resource| return resource}
raise ResolvError.new("DNS result has no information for #{name}")
end
Looks up all typeclass DNS resources for name. See getresource for argument details.
# File resolv.rb, line 483
def getresources(name, typeclass)
ret = []
each_resource(name, typeclass) {|resource| ret << resource}
return ret
end