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ruby--ruby/lib/resolv.rb

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# frozen_string_literal: true
require 'socket'
require 'timeout'
require 'io/wait'
begin
require 'securerandom'
rescue LoadError
end
# Resolv is a thread-aware DNS resolver library written in Ruby. Resolv can
# handle multiple DNS requests concurrently without blocking the entire Ruby
# interpreter.
#
# See also resolv-replace.rb to replace the libc resolver with Resolv.
#
# Resolv can look up various DNS resources using the DNS module directly.
#
# Examples:
#
# p Resolv.getaddress "www.ruby-lang.org"
# p Resolv.getname "210.251.121.214"
#
# Resolv::DNS.open do |dns|
# ress = dns.getresources "www.ruby-lang.org", Resolv::DNS::Resource::IN::A
# p ress.map(&:address)
# ress = dns.getresources "ruby-lang.org", Resolv::DNS::Resource::IN::MX
# p ress.map { |r| [r.exchange.to_s, r.preference] }
# end
#
#
# == Bugs
#
# * NIS is not supported.
# * /etc/nsswitch.conf is not supported.
class Resolv
##
# Looks up the first IP address for +name+.
def self.getaddress(name)
DefaultResolver.getaddress(name)
end
##
# Looks up all IP address for +name+.
def self.getaddresses(name)
DefaultResolver.getaddresses(name)
end
##
# Iterates over all IP addresses for +name+.
def self.each_address(name, &block)
DefaultResolver.each_address(name, &block)
end
##
# Looks up the hostname of +address+.
def self.getname(address)
DefaultResolver.getname(address)
end
##
# Looks up all hostnames for +address+.
def self.getnames(address)
DefaultResolver.getnames(address)
end
##
# Iterates over all hostnames for +address+.
def self.each_name(address, &proc)
DefaultResolver.each_name(address, &proc)
end
##
# Creates a new Resolv using +resolvers+.
def initialize(resolvers=[Hosts.new, DNS.new])
@resolvers = resolvers
end
##
# Looks up the first IP address for +name+.
def getaddress(name)
each_address(name) {|address| return address}
raise ResolvError.new("no address for #{name}")
end
##
# Looks up all IP address for +name+.
def getaddresses(name)
ret = []
each_address(name) {|address| ret << address}
return ret
end
##
# Iterates over all IP addresses for +name+.
def each_address(name)
if AddressRegex =~ name
yield name
return
end
yielded = false
@resolvers.each {|r|
r.each_address(name) {|address|
yield address.to_s
yielded = true
}
return if yielded
}
end
##
# Looks up the hostname of +address+.
def getname(address)
each_name(address) {|name| return name}
raise ResolvError.new("no name for #{address}")
end
##
# Looks up all hostnames for +address+.
def getnames(address)
ret = []
each_name(address) {|name| ret << name}
return ret
end
##
# Iterates over all hostnames for +address+.
def each_name(address)
yielded = false
@resolvers.each {|r|
r.each_name(address) {|name|
yield name.to_s
yielded = true
}
return if yielded
}
end
##
# Indicates a failure to resolve a name or address.
class ResolvError < StandardError; end
##
# Indicates a timeout resolving a name or address.
class ResolvTimeout < Timeout::Error; end
##
# Resolv::Hosts is a hostname resolver that uses the system hosts file.
class Hosts
if /mswin|mingw|cygwin/ =~ RUBY_PLATFORM and
begin
require 'win32/resolv'
DefaultFileName = Win32::Resolv.get_hosts_path || IO::NULL
rescue LoadError
end
end
DefaultFileName ||= '/etc/hosts'
##
# Creates a new Resolv::Hosts, using +filename+ for its data source.
def initialize(filename = DefaultFileName)
@filename = filename
@mutex = Thread::Mutex.new
@initialized = nil
end
def lazy_initialize # :nodoc:
@mutex.synchronize {
unless @initialized
@name2addr = {}
@addr2name = {}
File.open(@filename, 'rb') {|f|
f.each {|line|
line.sub!(/#.*/, '')
addr, hostname, *aliases = line.split(/\s+/)
next unless addr
@addr2name[addr] = [] unless @addr2name.include? addr
@addr2name[addr] << hostname
@addr2name[addr] += aliases
@name2addr[hostname] = [] unless @name2addr.include? hostname
@name2addr[hostname] << addr
aliases.each {|n|
@name2addr[n] = [] unless @name2addr.include? n
@name2addr[n] << addr
}
}
}
@name2addr.each {|name, arr| arr.reverse!}
@initialized = true
end
}
self
end
##
# Gets the IP address of +name+ from the hosts file.
def getaddress(name)
each_address(name) {|address| return address}
raise ResolvError.new("#{@filename} has no name: #{name}")
end
##
# Gets all IP addresses for +name+ from the hosts file.
def getaddresses(name)
ret = []
each_address(name) {|address| ret << address}
return ret
end
##
# Iterates over all IP addresses for +name+ retrieved from the hosts file.
def each_address(name, &proc)
lazy_initialize
@name2addr[name]&.each(&proc)
end
##
# Gets the hostname of +address+ from the hosts file.
def getname(address)
each_name(address) {|name| return name}
raise ResolvError.new("#{@filename} has no address: #{address}")
end
##
# Gets all hostnames for +address+ from the hosts file.
def getnames(address)
ret = []
each_name(address) {|name| ret << name}
return ret
end
##
# Iterates over all hostnames for +address+ retrieved from the hosts file.
def each_name(address, &proc)
lazy_initialize
@addr2name[address]&.each(&proc)
end
end
##
# Resolv::DNS is a DNS stub resolver.
#
# Information taken from the following places:
#
# * STD0013
# * RFC 1035
# * ftp://ftp.isi.edu/in-notes/iana/assignments/dns-parameters
# * etc.
class DNS
##
# Default DNS Port
Port = 53
##
# Default DNS UDP packet size
UDPSize = 512
##
# 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.
def self.open(*args)
dns = new(*args)
return dns unless block_given?
begin
yield dns
ensure
dns.close
end
end
##
# 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)
def initialize(config_info=nil)
@mutex = Thread::Mutex.new
@config = Config.new(config_info)
@initialized = nil
end
# Sets the resolver timeouts. This may be a single positive number
# or an array of positive numbers representing timeouts in seconds.
# If an array is specified, a DNS request will retry and wait for
# each successive interval in the array until a successful response
# is received. Specifying +nil+ reverts to the default timeouts:
# [ 5, second = 5 * 2 / nameserver_count, 2 * second, 4 * second ]
#
# Example:
#
# dns.timeouts = 3
#
def timeouts=(values)
@config.timeouts = values
end
def lazy_initialize # :nodoc:
@mutex.synchronize {
unless @initialized
@config.lazy_initialize
@initialized = true
end
}
self
end
##
# Closes the DNS resolver.
def close
@mutex.synchronize {
if @initialized
@initialized = false
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
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
def getaddresses(name)
ret = []
each_address(name) {|address| ret << address}
return ret
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
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
def use_ipv6? # :nodoc:
begin
list = Socket.ip_address_list
rescue NotImplementedError
return true
end
list.any? {|a| a.ipv6? && !a.ipv6_loopback? && !a.ipv6_linklocal? }
end
private :use_ipv6?
##
# 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.
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.
def getnames(address)
ret = []
each_name(address) {|name| ret << name}
return ret
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.
def each_name(address)
case address
when Name
ptr = address
when IPv4, IPv6
ptr = address.to_name
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
##
# 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::A
# * Resolv::DNS::Resource::IN::AAAA
# * 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
# * Resolv::DNS::Resource::IN::WKS
#
# Returned resource is represented as a Resolv::DNS::Resource instance,
# i.e. Resolv::DNS::Resource::IN::A.
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.
def getresources(name, typeclass)
ret = []
each_resource(name, typeclass) {|resource| ret << resource}
return ret
end
##
# Iterates over all +typeclass+ DNS resources for +name+. See
# #getresource for argument details.
def each_resource(name, typeclass, &proc)
fetch_resource(name, typeclass) {|reply, reply_name|
extract_resources(reply, reply_name, typeclass, &proc)
}
end
def fetch_resource(name, typeclass)
lazy_initialize
begin
requester = make_udp_requester
rescue Errno::EACCES
# fall back to TCP
end
senders = {}
begin
@config.resolv(name) {|candidate, tout, nameserver, port|
requester ||= make_tcp_requester(nameserver, port)
msg = Message.new
msg.rd = 1
msg.add_question(candidate, typeclass)
unless sender = senders[[candidate, nameserver, port]]
sender = requester.sender(msg, candidate, nameserver, port)
next if !sender
senders[[candidate, nameserver, port]] = sender
end
reply, reply_name = requester.request(sender, tout)
case reply.rcode
when RCode::NoError
if reply.tc == 1 and not Requester::TCP === requester
requester.close
# Retry via TCP:
requester = make_tcp_requester(nameserver, port)
senders = {}
# This will use TCP for all remaining candidates (assuming the
# current candidate does not already respond successfully via
# TCP). This makes sense because we already know the full
# response will not fit in an untruncated UDP packet.
redo
else
yield(reply, reply_name)
end
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
def make_udp_requester # :nodoc:
nameserver_port = @config.nameserver_port
if nameserver_port.length == 1
Requester::ConnectedUDP.new(*nameserver_port[0])
else
Requester::UnconnectedUDP.new(*nameserver_port)
end
end
def make_tcp_requester(host, port) # :nodoc:
return Requester::TCP.new(host, port)
end
def extract_resources(msg, name, typeclass) # :nodoc:
if typeclass < Resource::ANY
n0 = Name.create(name)
msg.each_resource {|n, ttl, data|
yield data if n0 == n
}
end
yielded = false
n0 = Name.create(name)
msg.each_resource {|n, ttl, data|
if n0 == n
case data
when typeclass
yield data
yielded = true
when Resource::CNAME
n0 = data.name
end
end
}
return if yielded
msg.each_resource {|n, ttl, data|
if n0 == n
case data
when typeclass
yield data
end
end
}
end
if defined? SecureRandom
def self.random(arg) # :nodoc:
begin
SecureRandom.random_number(arg)
rescue NotImplementedError
rand(arg)
end
end
else
def self.random(arg) # :nodoc:
rand(arg)
end
end
RequestID = {} # :nodoc:
RequestIDMutex = Thread::Mutex.new # :nodoc:
def self.allocate_request_id(host, port) # :nodoc:
id = nil
RequestIDMutex.synchronize {
h = (RequestID[[host, port]] ||= {})
begin
id = random(0x0000..0xffff)
end while h[id]
h[id] = true
}
id
end
def self.free_request_id(host, port, id) # :nodoc:
RequestIDMutex.synchronize {
key = [host, port]
if h = RequestID[key]
h.delete id
if h.empty?
RequestID.delete key
end
end
}
end
def self.bind_random_port(udpsock, bind_host="0.0.0.0") # :nodoc:
begin
port = random(1024..65535)
udpsock.bind(bind_host, port)
rescue Errno::EADDRINUSE, # POSIX
Errno::EACCES, # SunOS: See PRIV_SYS_NFS in privileges(5)
Errno::EPERM # FreeBSD: security.mac.portacl.port_high is configurable. See mac_portacl(4).
retry
end
end
class Requester # :nodoc:
def initialize
@senders = {}
@socks = nil
end
def request(sender, tout)
start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
timelimit = start + tout
begin
sender.send
rescue Errno::EHOSTUNREACH, # multi-homed IPv6 may generate this
Errno::ENETUNREACH
raise ResolvTimeout
end
while true
before_select = Process.clock_gettime(Process::CLOCK_MONOTONIC)
timeout = timelimit - before_select
if timeout <= 0
raise ResolvTimeout
end
if @socks.size == 1
select_result = @socks[0].wait_readable(timeout) ? [ @socks ] : nil
else
select_result = IO.select(@socks, nil, nil, timeout)
end
if !select_result
after_select = Process.clock_gettime(Process::CLOCK_MONOTONIC)
next if after_select < timelimit
raise ResolvTimeout
end
begin
reply, from = recv_reply(select_result[0])
rescue Errno::ECONNREFUSED, # GNU/Linux, FreeBSD
Errno::ECONNRESET # Windows
# No name server running on the server?
# Don't wait anymore.
raise ResolvTimeout
end
begin
msg = Message.decode(reply)
rescue DecodeError
next # broken DNS message ignored
end
if sender == sender_for(from, msg)
break
else
# unexpected DNS message ignored
end
end
return msg, sender.data
end
def sender_for(addr, msg)
@senders[[addr,msg.id]]
end
def close
socks = @socks
@socks = nil
socks&.each(&:close)
end
class Sender # :nodoc:
def initialize(msg, data, sock)
@msg = msg
@data = data
@sock = sock
end
end
class UnconnectedUDP < Requester # :nodoc:
def initialize(*nameserver_port)
super()
@nameserver_port = nameserver_port
@initialized = false
@mutex = Thread::Mutex.new
end
def lazy_initialize
@mutex.synchronize {
next if @initialized
@initialized = true
@socks_hash = {}
@socks = []
@nameserver_port.each {|host, port|
if host.index(':')
bind_host = "::"
af = Socket::AF_INET6
else
bind_host = "0.0.0.0"
af = Socket::AF_INET
end
next if @socks_hash[bind_host]
begin
sock = UDPSocket.new(af)
rescue Errno::EAFNOSUPPORT
next # The kernel doesn't support the address family.
end
@socks << sock
@socks_hash[bind_host] = sock
sock.do_not_reverse_lookup = true
DNS.bind_random_port(sock, bind_host)
}
}
self
end
def recv_reply(readable_socks)
lazy_initialize
reply, from = readable_socks[0].recvfrom(UDPSize)
return reply, [from[3],from[1]]
end
def sender(msg, data, host, port=Port)
host = Addrinfo.ip(host).ip_address
lazy_initialize
sock = @socks_hash[host.index(':') ? "::" : "0.0.0.0"]
return nil if !sock
service = [host, port]
id = DNS.allocate_request_id(host, port)
request = msg.encode
request[0,2] = [id].pack('n')
return @senders[[service, id]] =
Sender.new(request, data, sock, host, port)
end
def close
@mutex.synchronize {
if @initialized
super
@senders.each_key {|service, id|
DNS.free_request_id(service[0], service[1], id)
}
@initialized = false
end
}
end
class Sender < Requester::Sender # :nodoc:
def initialize(msg, data, sock, host, port)
super(msg, data, sock)
@host = host
@port = port
end
attr_reader :data
def send
raise "@sock is nil." if @sock.nil?
@sock.send(@msg, 0, @host, @port)
end
end
end
class ConnectedUDP < Requester # :nodoc:
def initialize(host, port=Port)
super()
@host = host
@port = port
@mutex = Thread::Mutex.new
@initialized = false
end
def lazy_initialize
@mutex.synchronize {
next if @initialized
@initialized = true
is_ipv6 = @host.index(':')
sock = UDPSocket.new(is_ipv6 ? Socket::AF_INET6 : Socket::AF_INET)
@socks = [sock]
sock.do_not_reverse_lookup = true
DNS.bind_random_port(sock, is_ipv6 ? "::" : "0.0.0.0")
sock.connect(@host, @port)
}
self
end
def recv_reply(readable_socks)
lazy_initialize
reply = readable_socks[0].recv(UDPSize)
return reply, nil
end
def sender(msg, data, host=@host, port=@port)
lazy_initialize
unless host == @host && port == @port
raise RequestError.new("host/port don't match: #{host}:#{port}")
end
id = DNS.allocate_request_id(@host, @port)
request = msg.encode
request[0,2] = [id].pack('n')
return @senders[[nil,id]] = Sender.new(request, data, @socks[0])
end
def close
@mutex.synchronize do
if @initialized
super
@senders.each_key {|from, id|
DNS.free_request_id(@host, @port, id)
}
@initialized = false
end
end
end
class Sender < Requester::Sender # :nodoc:
def send
raise "@sock is nil." if @sock.nil?
@sock.send(@msg, 0)
end
attr_reader :data
end
end
class MDNSOneShot < UnconnectedUDP # :nodoc:
def sender(msg, data, host, port=Port)
lazy_initialize
id = DNS.allocate_request_id(host, port)
request = msg.encode
request[0,2] = [id].pack('n')
sock = @socks_hash[host.index(':') ? "::" : "0.0.0.0"]
return @senders[id] =
UnconnectedUDP::Sender.new(request, data, sock, host, port)
end
def sender_for(addr, msg)
lazy_initialize
@senders[msg.id]
end
end
class TCP < Requester # :nodoc:
def initialize(host, port=Port)
super()
@host = host
@port = port
sock = TCPSocket.new(@host, @port)
@socks = [sock]
@senders = {}
end
def recv_reply(readable_socks)
len = readable_socks[0].read(2).unpack('n')[0]
reply = @socks[0].read(len)
return reply, nil
end
def sender(msg, data, host=@host, port=@port)
unless host == @host && port == @port
raise RequestError.new("host/port don't match: #{host}:#{port}")
end
id = DNS.allocate_request_id(@host, @port)
request = msg.encode
request[0,2] = [request.length, id].pack('nn')
return @senders[[nil,id]] = Sender.new(request, data, @socks[0])
end
class Sender < Requester::Sender # :nodoc:
def send
@sock.print(@msg)
@sock.flush
end
attr_reader :data
end
def close
super
@senders.each_key {|from,id|
DNS.free_request_id(@host, @port, id)
}
end
end
##
# Indicates a problem with the DNS request.
class RequestError < StandardError
end
end
class Config # :nodoc:
def initialize(config_info=nil)
@mutex = Thread::Mutex.new
@config_info = config_info
@initialized = nil
@timeouts = nil
end
def timeouts=(values)
if values
values = Array(values)
values.each do |t|
Numeric === t or raise ArgumentError, "#{t.inspect} is not numeric"
t > 0.0 or raise ArgumentError, "timeout=#{t} must be positive"
end
@timeouts = values
else
@timeouts = nil
end
end
def Config.parse_resolv_conf(filename)
nameserver = []
search = nil
ndots = 1
File.open(filename, 'rb') {|f|
f.each {|line|
line.sub!(/[#;].*/, '')
keyword, *args = line.split(/\s+/)
next unless keyword
case keyword
when 'nameserver'
nameserver += args
when 'domain'
next if args.empty?
search = [args[0]]
when 'search'
next if args.empty?
search = args
when 'options'
args.each {|arg|
case arg
when /\Andots:(\d+)\z/
ndots = $1.to_i
end
}
end
}
}
return { :nameserver => nameserver, :search => search, :ndots => ndots }
end
def Config.default_config_hash(filename="/etc/resolv.conf")
if File.exist? filename
config_hash = Config.parse_resolv_conf(filename)
else
if /mswin|cygwin|mingw|bccwin/ =~ RUBY_PLATFORM
require 'win32/resolv'
search, nameserver = Win32::Resolv.get_resolv_info
config_hash = {}
config_hash[:nameserver] = nameserver if nameserver
config_hash[:search] = [search].flatten if search
end
end
config_hash || {}
end
def lazy_initialize
@mutex.synchronize {
unless @initialized
@nameserver_port = []
@search = nil
@ndots = 1
case @config_info
when nil
config_hash = Config.default_config_hash
when String
config_hash = Config.parse_resolv_conf(@config_info)
when Hash
config_hash = @config_info.dup
if String === config_hash[:nameserver]
config_hash[:nameserver] = [config_hash[:nameserver]]
end
if String === config_hash[:search]
config_hash[:search] = [config_hash[:search]]
end
else
raise ArgumentError.new("invalid resolv configuration: #{@config_info.inspect}")
end
if config_hash.include? :nameserver
@nameserver_port = config_hash[:nameserver].map {|ns| [ns, Port] }
end
if config_hash.include? :nameserver_port
@nameserver_port = config_hash[:nameserver_port].map {|ns, port| [ns, (port || Port)] }
end
@search = config_hash[:search] if config_hash.include? :search
@ndots = config_hash[:ndots] if config_hash.include? :ndots
if @nameserver_port.empty?
@nameserver_port << ['0.0.0.0', Port]
end
if @search
@search = @search.map {|arg| Label.split(arg) }
else
hostname = Socket.gethostname
if /\./ =~ hostname
@search = [Label.split($')]
else
@search = [[]]
end
end
if !@nameserver_port.kind_of?(Array) ||
@nameserver_port.any? {|ns_port|
!(Array === ns_port) ||
ns_port.length != 2
!(String === ns_port[0]) ||
!(Integer === ns_port[1])
}
raise ArgumentError.new("invalid nameserver config: #{@nameserver_port.inspect}")
end
if !@search.kind_of?(Array) ||
!@search.all? {|ls| ls.all? {|l| Label::Str === l } }
raise ArgumentError.new("invalid search config: #{@search.inspect}")
end
if !@ndots.kind_of?(Integer)
raise ArgumentError.new("invalid ndots config: #{@ndots.inspect}")
end
@initialized = true
end
}
self
end
def single?
lazy_initialize
if @nameserver_port.length == 1
return @nameserver_port[0]
else
return nil
end
end
def nameserver_port
@nameserver_port
end
def generate_candidates(name)
candidates = nil
name = Name.create(name)
if name.absolute?
candidates = [name]
else
if @ndots <= name.length - 1
candidates = [Name.new(name.to_a)]
else
candidates = []
end
candidates.concat(@search.map {|domain| Name.new(name.to_a + domain)})
fname = Name.create("#{name}.")
if !candidates.include?(fname)
candidates << fname
end
end
return candidates
end
InitialTimeout = 5
def generate_timeouts
ts = [InitialTimeout]
ts << ts[-1] * 2 / @nameserver_port.length
ts << ts[-1] * 2
ts << ts[-1] * 2
return ts
end
def resolv(name)
candidates = generate_candidates(name)
timeouts = @timeouts || generate_timeouts
begin
candidates.each {|candidate|
begin
timeouts.each {|tout|
@nameserver_port.each {|nameserver, port|
begin
yield candidate, tout, nameserver, port
rescue ResolvTimeout
end
}
}
raise ResolvError.new("DNS resolv timeout: #{name}")
rescue NXDomain
end
}
rescue ResolvError
end
end
##
# Indicates no such domain was found.
class NXDomain < ResolvError
end
##
# Indicates some other unhandled resolver error was encountered.
class OtherResolvError < ResolvError
end
end
module OpCode # :nodoc:
Query = 0
IQuery = 1
Status = 2
Notify = 4
Update = 5
end
module RCode # :nodoc:
NoError = 0
FormErr = 1
ServFail = 2
NXDomain = 3
NotImp = 4
Refused = 5
YXDomain = 6
YXRRSet = 7
NXRRSet = 8
NotAuth = 9
NotZone = 10
BADVERS = 16
BADSIG = 16
BADKEY = 17
BADTIME = 18
BADMODE = 19
BADNAME = 20
BADALG = 21
end
##
# Indicates that the DNS response was unable to be decoded.
class DecodeError < StandardError
end
##
# Indicates that the DNS request was unable to be encoded.
class EncodeError < StandardError
end
module Label # :nodoc:
def self.split(arg)
labels = []
arg.scan(/[^\.]+/) {labels << Str.new($&)}
return labels
end
class Str # :nodoc:
def initialize(string)
@string = string
# case insensivity of DNS labels doesn't apply non-ASCII characters. [RFC 4343]
# This assumes @string is given in ASCII compatible encoding.
@downcase = string.b.downcase
end
attr_reader :string, :downcase
def to_s
return @string
end
def inspect
return "#<#{self.class} #{self}>"
end
def ==(other)
return self.class == other.class && @downcase == other.downcase
end
def eql?(other)
return self == other
end
def hash
return @downcase.hash
end
end
end
##
# A representation of a DNS name.
class Name
##
# Creates a new DNS name from +arg+. +arg+ can be:
#
# Name:: returns +arg+.
# String:: Creates a new Name.
def self.create(arg)
case arg
when Name
return arg
when String
return Name.new(Label.split(arg), /\.\z/ =~ arg ? true : false)
else
raise ArgumentError.new("cannot interpret as DNS name: #{arg.inspect}")
end
end
def initialize(labels, absolute=true) # :nodoc:
labels = labels.map {|label|
case label
when String then Label::Str.new(label)
when Label::Str then label
else
raise ArgumentError, "unexpected label: #{label.inspect}"
end
}
@labels = labels
@absolute = absolute
end
def inspect # :nodoc:
"#<#{self.class}: #{self}#{@absolute ? '.' : ''}>"
end
##
# True if this name is absolute.
def absolute?
return @absolute
end
def ==(other) # :nodoc:
return false unless Name === other
return false unless @absolute == other.absolute?
return @labels == other.to_a
end
alias eql? == # :nodoc:
##
# Returns true if +other+ is a subdomain.
#
# Example:
#
# domain = Resolv::DNS::Name.create("y.z")
# p Resolv::DNS::Name.create("w.x.y.z").subdomain_of?(domain) #=> true
# p Resolv::DNS::Name.create("x.y.z").subdomain_of?(domain) #=> true
# p Resolv::DNS::Name.create("y.z").subdomain_of?(domain) #=> false
# p Resolv::DNS::Name.create("z").subdomain_of?(domain) #=> false
# p Resolv::DNS::Name.create("x.y.z.").subdomain_of?(domain) #=> false
# p Resolv::DNS::Name.create("w.z").subdomain_of?(domain) #=> false
#
def subdomain_of?(other)
raise ArgumentError, "not a domain name: #{other.inspect}" unless Name === other
return false if @absolute != other.absolute?
other_len = other.length
return false if @labels.length <= other_len
return @labels[-other_len, other_len] == other.to_a
end
def hash # :nodoc:
return @labels.hash ^ @absolute.hash
end
def to_a # :nodoc:
return @labels
end
def length # :nodoc:
return @labels.length
end
def [](i) # :nodoc:
return @labels[i]
end
##
# returns the domain name as a string.
#
# The domain name doesn't have a trailing dot even if the name object is
# absolute.
#
# Example:
#
# p Resolv::DNS::Name.create("x.y.z.").to_s #=> "x.y.z"
# p Resolv::DNS::Name.create("x.y.z").to_s #=> "x.y.z"
def to_s
return @labels.join('.')
end
end
class Message # :nodoc:
@@identifier = -1
def initialize(id = (@@identifier += 1) & 0xffff)
@id = id
@qr = 0
@opcode = 0
@aa = 0
@tc = 0
@rd = 0 # recursion desired
@ra = 0 # recursion available
@rcode = 0
@question = []
@answer = []
@authority = []
@additional = []
end
attr_accessor :id, :qr, :opcode, :aa, :tc, :rd, :ra, :rcode
attr_reader :question, :answer, :authority, :additional
def ==(other)
return @id == other.id &&
@qr == other.qr &&
@opcode == other.opcode &&
@aa == other.aa &&
@tc == other.tc &&
@rd == other.rd &&
@ra == other.ra &&
@rcode == other.rcode &&
@question == other.question &&
@answer == other.answer &&
@authority == other.authority &&
@additional == other.additional
end
def add_question(name, typeclass)
@question << [Name.create(name), typeclass]
end
def each_question
@question.each {|name, typeclass|
yield name, typeclass
}
end
def add_answer(name, ttl, data)
@answer << [Name.create(name), ttl, data]
end
def each_answer
@answer.each {|name, ttl, data|
yield name, ttl, data
}
end
def add_authority(name, ttl, data)
@authority << [Name.create(name), ttl, data]
end
def each_authority
@authority.each {|name, ttl, data|
yield name, ttl, data
}
end
def add_additional(name, ttl, data)
@additional << [Name.create(name), ttl, data]
end
def each_additional
@additional.each {|name, ttl, data|
yield name, ttl, data
}
end
def each_resource
each_answer {|name, ttl, data| yield name, ttl, data}
each_authority {|name, ttl, data| yield name, ttl, data}
each_additional {|name, ttl, data| yield name, ttl, data}
end
def encode
return MessageEncoder.new {|msg|
msg.put_pack('nnnnnn',
@id,
(@qr & 1) << 15 |
(@opcode & 15) << 11 |
(@aa & 1) << 10 |
(@tc & 1) << 9 |
(@rd & 1) << 8 |
(@ra & 1) << 7 |
(@rcode & 15),
@question.length,
@answer.length,
@authority.length,
@additional.length)
@question.each {|q|
name, typeclass = q
msg.put_name(name)
msg.put_pack('nn', typeclass::TypeValue, typeclass::ClassValue)
}
[@answer, @authority, @additional].each {|rr|
rr.each {|r|
name, ttl, data = r
msg.put_name(name)
msg.put_pack('nnN', data.class::TypeValue, data.class::ClassValue, ttl)
msg.put_length16 {data.encode_rdata(msg)}
}
}
}.to_s
end
class MessageEncoder # :nodoc:
def initialize
@data = ''.dup
@names = {}
yield self
end
def to_s
return @data
end
def put_bytes(d)
@data << d
end
def put_pack(template, *d)
@data << d.pack(template)
end
def put_length16
length_index = @data.length
@data << "\0\0"
data_start = @data.length
yield
data_end = @data.length
@data[length_index, 2] = [data_end - data_start].pack("n")
end
def put_string(d)
self.put_pack("C", d.length)
@data << d
end
def put_string_list(ds)
ds.each {|d|
self.put_string(d)
}
end
def put_name(d)
put_labels(d.to_a)
end
def put_labels(d)
d.each_index {|i|
domain = d[i..-1]
if idx = @names[domain]
self.put_pack("n", 0xc000 | idx)
return
else
if @data.length < 0x4000
@names[domain] = @data.length
end
self.put_label(d[i])
end
}
@data << "\0"
end
def put_label(d)
self.put_string(d.to_s)
end
end
def Message.decode(m)
o = Message.new(0)
MessageDecoder.new(m) {|msg|
id, flag, qdcount, ancount, nscount, arcount =
msg.get_unpack('nnnnnn')
o.id = id
o.qr = (flag >> 15) & 1
o.opcode = (flag >> 11) & 15
o.aa = (flag >> 10) & 1
o.tc = (flag >> 9) & 1
o.rd = (flag >> 8) & 1
o.ra = (flag >> 7) & 1
o.rcode = flag & 15
(1..qdcount).each {
name, typeclass = msg.get_question
o.add_question(name, typeclass)
}
(1..ancount).each {
name, ttl, data = msg.get_rr
o.add_answer(name, ttl, data)
}
(1..nscount).each {
name, ttl, data = msg.get_rr
o.add_authority(name, ttl, data)
}
(1..arcount).each {
name, ttl, data = msg.get_rr
o.add_additional(name, ttl, data)
}
}
return o
end
class MessageDecoder # :nodoc:
def initialize(data)
@data = data
@index = 0
@limit = data.bytesize
yield self
end
def inspect
"\#<#{self.class}: #{@data.byteslice(0, @index).inspect} #{@data.byteslice(@index..-1).inspect}>"
end
def get_length16
len, = self.get_unpack('n')
save_limit = @limit
@limit = @index + len
d = yield(len)
if @index < @limit
raise DecodeError.new("junk exists")
elsif @limit < @index
raise DecodeError.new("limit exceeded")
end
@limit = save_limit
return d
end
def get_bytes(len = @limit - @index)
raise DecodeError.new("limit exceeded") if @limit < @index + len
d = @data.byteslice(@index, len)
@index += len
return d
end
def get_unpack(template)
len = 0
template.each_byte {|byte|
byte = "%c" % byte
case byte
when ?c, ?C
len += 1
when ?n
len += 2
when ?N
len += 4
else
raise StandardError.new("unsupported template: '#{byte.chr}' in '#{template}'")
end
}
raise DecodeError.new("limit exceeded") if @limit < @index + len
arr = @data.unpack("@#{@index}#{template}")
@index += len
return arr
end
def get_string
raise DecodeError.new("limit exceeded") if @limit <= @index
len = @data.getbyte(@index)
raise DecodeError.new("limit exceeded") if @limit < @index + 1 + len
d = @data.byteslice(@index + 1, len)
@index += 1 + len
return d
end
def get_string_list
strings = []
while @index < @limit
strings << self.get_string
end
strings
end
def get_name
return Name.new(self.get_labels)
end
def get_labels
prev_index = @index
save_index = nil
d = []
while true
raise DecodeError.new("limit exceeded") if @limit <= @index
case @data.getbyte(@index)
when 0
@index += 1
if save_index
@index = save_index
end
return d
when 192..255
idx = self.get_unpack('n')[0] & 0x3fff
if prev_index <= idx
raise DecodeError.new("non-backward name pointer")
end
prev_index = idx
if !save_index
save_index = @index
end
@index = idx
else
d << self.get_label
end
end
end
def get_label
return Label::Str.new(self.get_string)
end
def get_question
name = self.get_name
type, klass = self.get_unpack("nn")
return name, Resource.get_class(type, klass)
end
def get_rr
name = self.get_name
type, klass, ttl = self.get_unpack('nnN')
typeclass = Resource.get_class(type, klass)
res = self.get_length16 do
begin
typeclass.decode_rdata self
rescue => e
raise DecodeError, e.message, e.backtrace
end
end
res.instance_variable_set :@ttl, ttl
return name, ttl, res
end
end
end
##
# A DNS query abstract class.
class Query
def encode_rdata(msg) # :nodoc:
raise EncodeError.new("#{self.class} is query.")
end
def self.decode_rdata(msg) # :nodoc:
raise DecodeError.new("#{self.class} is query.")
end
end
##
# A DNS resource abstract class.
class Resource < Query
##
# Remaining Time To Live for this Resource.
attr_reader :ttl
ClassHash = {} # :nodoc:
def encode_rdata(msg) # :nodoc:
raise NotImplementedError.new
end
def self.decode_rdata(msg) # :nodoc:
raise NotImplementedError.new
end
def ==(other) # :nodoc:
return false unless self.class == other.class
s_ivars = self.instance_variables
s_ivars.sort!
s_ivars.delete :@ttl
o_ivars = other.instance_variables
o_ivars.sort!
o_ivars.delete :@ttl
return s_ivars == o_ivars &&
s_ivars.collect {|name| self.instance_variable_get name} ==
o_ivars.collect {|name| other.instance_variable_get name}
end
def eql?(other) # :nodoc:
return self == other
end
def hash # :nodoc:
h = 0
vars = self.instance_variables
vars.delete :@ttl
vars.each {|name|
h ^= self.instance_variable_get(name).hash
}
return h
end
def self.get_class(type_value, class_value) # :nodoc:
return ClassHash[[type_value, class_value]] ||
Generic.create(type_value, class_value)
end
##
# A generic resource abstract class.
class Generic < Resource
##
# Creates a new generic resource.
def initialize(data)
@data = data
end
##
# Data for this generic resource.
attr_reader :data
def encode_rdata(msg) # :nodoc:
msg.put_bytes(data)
end
def self.decode_rdata(msg) # :nodoc:
return self.new(msg.get_bytes)
end
def self.create(type_value, class_value) # :nodoc:
c = Class.new(Generic)
c.const_set(:TypeValue, type_value)
c.const_set(:ClassValue, class_value)
Generic.const_set("Type#{type_value}_Class#{class_value}", c)
ClassHash[[type_value, class_value]] = c
return c
end
end
##
# Domain Name resource abstract class.
class DomainName < Resource
##
# Creates a new DomainName from +name+.
def initialize(name)
@name = name
end
##
# The name of this DomainName.
attr_reader :name
def encode_rdata(msg) # :nodoc:
msg.put_name(@name)
end
def self.decode_rdata(msg) # :nodoc:
return self.new(msg.get_name)
end
end
# Standard (class generic) RRs
ClassValue = nil # :nodoc:
##
# An authoritative name server.
class NS < DomainName
TypeValue = 2 # :nodoc:
end
##
# The canonical name for an alias.
class CNAME < DomainName
TypeValue = 5 # :nodoc:
end
##
# Start Of Authority resource.
class SOA < Resource
TypeValue = 6 # :nodoc:
##
# Creates a new SOA record. See the attr documentation for the
# details of each argument.
def initialize(mname, rname, serial, refresh, retry_, expire, minimum)
@mname = mname
@rname = rname
@serial = serial
@refresh = refresh
@retry = retry_
@expire = expire
@minimum = minimum
end
##
# Name of the host where the master zone file for this zone resides.
attr_reader :mname
##
# The person responsible for this domain name.
attr_reader :rname
##
# The version number of the zone file.
attr_reader :serial
##
# How often, in seconds, a secondary name server is to check for
# updates from the primary name server.
attr_reader :refresh
##
# How often, in seconds, a secondary name server is to retry after a
# failure to check for a refresh.
attr_reader :retry
##
# Time in seconds that a secondary name server is to use the data
# before refreshing from the primary name server.
attr_reader :expire
##
# The minimum number of seconds to be used for TTL values in RRs.
attr_reader :minimum
def encode_rdata(msg) # :nodoc:
msg.put_name(@mname)
msg.put_name(@rname)
msg.put_pack('NNNNN', @serial, @refresh, @retry, @expire, @minimum)
end
def self.decode_rdata(msg) # :nodoc:
mname = msg.get_name
rname = msg.get_name
serial, refresh, retry_, expire, minimum = msg.get_unpack('NNNNN')
return self.new(
mname, rname, serial, refresh, retry_, expire, minimum)
end
end
##
# A Pointer to another DNS name.
class PTR < DomainName
TypeValue = 12 # :nodoc:
end
##
# Host Information resource.
class HINFO < Resource
TypeValue = 13 # :nodoc:
##
# Creates a new HINFO running +os+ on +cpu+.
def initialize(cpu, os)
@cpu = cpu
@os = os
end
##
# CPU architecture for this resource.
attr_reader :cpu
##
# Operating system for this resource.
attr_reader :os
def encode_rdata(msg) # :nodoc:
msg.put_string(@cpu)
msg.put_string(@os)
end
def self.decode_rdata(msg) # :nodoc:
cpu = msg.get_string
os = msg.get_string
return self.new(cpu, os)
end
end
##
# Mailing list or mailbox information.
class MINFO < Resource
TypeValue = 14 # :nodoc:
def initialize(rmailbx, emailbx)
@rmailbx = rmailbx
@emailbx = emailbx
end
##
# Domain name responsible for this mail list or mailbox.
attr_reader :rmailbx
##
# Mailbox to use for error messages related to the mail list or mailbox.
attr_reader :emailbx
def encode_rdata(msg) # :nodoc:
msg.put_name(@rmailbx)
msg.put_name(@emailbx)
end
def self.decode_rdata(msg) # :nodoc:
rmailbx = msg.get_string
emailbx = msg.get_string
return self.new(rmailbx, emailbx)
end
end
##
# Mail Exchanger resource.
class MX < Resource
TypeValue= 15 # :nodoc:
##
# Creates a new MX record with +preference+, accepting mail at
# +exchange+.
def initialize(preference, exchange)
@preference = preference
@exchange = exchange
end
##
# The preference for this MX.
attr_reader :preference
##
# The host of this MX.
attr_reader :exchange
def encode_rdata(msg) # :nodoc:
msg.put_pack('n', @preference)
msg.put_name(@exchange)
end
def self.decode_rdata(msg) # :nodoc:
preference, = msg.get_unpack('n')
exchange = msg.get_name
return self.new(preference, exchange)
end
end
##
# Unstructured text resource.
class TXT < Resource
TypeValue = 16 # :nodoc:
def initialize(first_string, *rest_strings)
@strings = [first_string, *rest_strings]
end
##
# Returns an Array of Strings for this TXT record.
attr_reader :strings
##
# Returns the concatenated string from +strings+.
def data
@strings.join("")
end
def encode_rdata(msg) # :nodoc:
msg.put_string_list(@strings)
end
def self.decode_rdata(msg) # :nodoc:
strings = msg.get_string_list
return self.new(*strings)
end
end
##
# Location resource
class LOC < Resource
TypeValue = 29 # :nodoc:
def initialize(version, ssize, hprecision, vprecision, latitude, longitude, altitude)
@version = version
@ssize = Resolv::LOC::Size.create(ssize)
@hprecision = Resolv::LOC::Size.create(hprecision)
@vprecision = Resolv::LOC::Size.create(vprecision)
@latitude = Resolv::LOC::Coord.create(latitude)
@longitude = Resolv::LOC::Coord.create(longitude)
@altitude = Resolv::LOC::Alt.create(altitude)
end
##
# Returns the version value for this LOC record which should always be 00
attr_reader :version
##
# The spherical size of this LOC
# in meters using scientific notation as 2 integers of XeY
attr_reader :ssize
##
# The horizontal precision using ssize type values
# in meters using scientific notation as 2 integers of XeY
# for precision use value/2 e.g. 2m = +/-1m
attr_reader :hprecision
##
# The vertical precision using ssize type values
# in meters using scientific notation as 2 integers of XeY
# for precision use value/2 e.g. 2m = +/-1m
attr_reader :vprecision
##
# The latitude for this LOC where 2**31 is the equator
# in thousandths of an arc second as an unsigned 32bit integer
attr_reader :latitude
##
# The longitude for this LOC where 2**31 is the prime meridian
# in thousandths of an arc second as an unsigned 32bit integer
attr_reader :longitude
##
# The altitude of the LOC above a reference sphere whose surface sits 100km below the WGS84 spheroid
# in centimeters as an unsigned 32bit integer
attr_reader :altitude
def encode_rdata(msg) # :nodoc:
msg.put_bytes(@version)
msg.put_bytes(@ssize.scalar)
msg.put_bytes(@hprecision.scalar)
msg.put_bytes(@vprecision.scalar)
msg.put_bytes(@latitude.coordinates)
msg.put_bytes(@longitude.coordinates)
msg.put_bytes(@altitude.altitude)
end
def self.decode_rdata(msg) # :nodoc:
version = msg.get_bytes(1)
ssize = msg.get_bytes(1)
hprecision = msg.get_bytes(1)
vprecision = msg.get_bytes(1)
latitude = msg.get_bytes(4)
longitude = msg.get_bytes(4)
altitude = msg.get_bytes(4)
return self.new(
version,
Resolv::LOC::Size.new(ssize),
Resolv::LOC::Size.new(hprecision),
Resolv::LOC::Size.new(vprecision),
Resolv::LOC::Coord.new(latitude,"lat"),
Resolv::LOC::Coord.new(longitude,"lon"),
Resolv::LOC::Alt.new(altitude)
)
end
end
##
# A Query type requesting any RR.
class ANY < Query
TypeValue = 255 # :nodoc:
end
ClassInsensitiveTypes = [ # :nodoc:
NS, CNAME, SOA, PTR, HINFO, MINFO, MX, TXT, LOC, ANY
]
##
# module IN contains ARPA Internet specific RRs.
module IN
ClassValue = 1 # :nodoc:
ClassInsensitiveTypes.each {|s|
c = Class.new(s)
c.const_set(:TypeValue, s::TypeValue)
c.const_set(:ClassValue, ClassValue)
ClassHash[[s::TypeValue, ClassValue]] = c
self.const_set(s.name.sub(/.*::/, ''), c)
}
##
# IPv4 Address resource
class A < Resource
TypeValue = 1
ClassValue = IN::ClassValue
ClassHash[[TypeValue, ClassValue]] = self # :nodoc:
##
# Creates a new A for +address+.
def initialize(address)
@address = IPv4.create(address)
end
##
# The Resolv::IPv4 address for this A.
attr_reader :address
def encode_rdata(msg) # :nodoc:
msg.put_bytes(@address.address)
end
def self.decode_rdata(msg) # :nodoc:
return self.new(IPv4.new(msg.get_bytes(4)))
end
end
##
# Well Known Service resource.
class WKS < Resource
TypeValue = 11
ClassValue = IN::ClassValue
ClassHash[[TypeValue, ClassValue]] = self # :nodoc:
def initialize(address, protocol, bitmap)
@address = IPv4.create(address)
@protocol = protocol
@bitmap = bitmap
end
##
# The host these services run on.
attr_reader :address
##
# IP protocol number for these services.
attr_reader :protocol
##
# A bit map of enabled services on this host.
#
# If protocol is 6 (TCP) then the 26th bit corresponds to the SMTP
# service (port 25). If this bit is set, then an SMTP server should
# be listening on TCP port 25; if zero, SMTP service is not
# supported.
attr_reader :bitmap
def encode_rdata(msg) # :nodoc:
msg.put_bytes(@address.address)
msg.put_pack("n", @protocol)
msg.put_bytes(@bitmap)
end
def self.decode_rdata(msg) # :nodoc:
address = IPv4.new(msg.get_bytes(4))
protocol, = msg.get_unpack("n")
bitmap = msg.get_bytes
return self.new(address, protocol, bitmap)
end
end
##
# An IPv6 address record.
class AAAA < Resource
TypeValue = 28
ClassValue = IN::ClassValue
ClassHash[[TypeValue, ClassValue]] = self # :nodoc:
##
# Creates a new AAAA for +address+.
def initialize(address)
@address = IPv6.create(address)
end
##
# The Resolv::IPv6 address for this AAAA.
attr_reader :address
def encode_rdata(msg) # :nodoc:
msg.put_bytes(@address.address)
end
def self.decode_rdata(msg) # :nodoc:
return self.new(IPv6.new(msg.get_bytes(16)))
end
end
##
# SRV resource record defined in RFC 2782
#
# These records identify the hostname and port that a service is
# available at.
class SRV < Resource
TypeValue = 33
ClassValue = IN::ClassValue
ClassHash[[TypeValue, ClassValue]] = self # :nodoc:
# Create a SRV resource record.
#
# See the documentation for #priority, #weight, #port and #target
# for +priority+, +weight+, +port and +target+ respectively.
def initialize(priority, weight, port, target)
@priority = priority.to_int
@weight = weight.to_int
@port = port.to_int
@target = Name.create(target)
end
# The priority of this target host.
#
# A client MUST attempt to contact the target host with the
# lowest-numbered priority it can reach; target hosts with the same
# priority SHOULD be tried in an order defined by the weight field.
# The range is 0-65535. Note that it is not widely implemented and
# should be set to zero.
attr_reader :priority
# A server selection mechanism.
#
# The weight field specifies a relative weight for entries with the
# same priority. Larger weights SHOULD be given a proportionately
# higher probability of being selected. The range of this number is
# 0-65535. Domain administrators SHOULD use Weight 0 when there
# isn't any server selection to do, to make the RR easier to read
# for humans (less noisy). Note that it is not widely implemented
# and should be set to zero.
attr_reader :weight
# The port on this target host of this service.
#
# The range is 0-65535.
attr_reader :port
# The domain name of the target host.
#
# A target of "." means that the service is decidedly not available
# at this domain.
attr_reader :target
def encode_rdata(msg) # :nodoc:
msg.put_pack("n", @priority)
msg.put_pack("n", @weight)
msg.put_pack("n", @port)
msg.put_name(@target)
end
def self.decode_rdata(msg) # :nodoc:
priority, = msg.get_unpack("n")
weight, = msg.get_unpack("n")
port, = msg.get_unpack("n")
target = msg.get_name
return self.new(priority, weight, port, target)
end
end
end
end
end
##
# A Resolv::DNS IPv4 address.
class IPv4
##
# Regular expression IPv4 addresses must match.
Regex256 = /0
|1(?:[0-9][0-9]?)?
|2(?:[0-4][0-9]?|5[0-5]?|[6-9])?
|[3-9][0-9]?/x
Regex = /\A(#{Regex256})\.(#{Regex256})\.(#{Regex256})\.(#{Regex256})\z/
def self.create(arg)
case arg
when IPv4
return arg
when Regex
if (0..255) === (a = $1.to_i) &&
(0..255) === (b = $2.to_i) &&
(0..255) === (c = $3.to_i) &&
(0..255) === (d = $4.to_i)
return self.new([a, b, c, d].pack("CCCC"))
else
raise ArgumentError.new("IPv4 address with invalid value: " + arg)
end
else
raise ArgumentError.new("cannot interpret as IPv4 address: #{arg.inspect}")
end
end
def initialize(address) # :nodoc:
unless address.kind_of?(String)
raise ArgumentError, 'IPv4 address must be a string'
end
unless address.length == 4
raise ArgumentError, "IPv4 address expects 4 bytes but #{address.length} bytes"
end
@address = address
end
##
# A String representation of this IPv4 address.
##
# The raw IPv4 address as a String.
attr_reader :address
def to_s # :nodoc:
return sprintf("%d.%d.%d.%d", *@address.unpack("CCCC"))
end
def inspect # :nodoc:
return "#<#{self.class} #{self}>"
end
##
# Turns this IPv4 address into a Resolv::DNS::Name.
def to_name
return DNS::Name.create(
'%d.%d.%d.%d.in-addr.arpa.' % @address.unpack('CCCC').reverse)
end
def ==(other) # :nodoc:
return @address == other.address
end
def eql?(other) # :nodoc:
return self == other
end
def hash # :nodoc:
return @address.hash
end
end
##
# A Resolv::DNS IPv6 address.
class IPv6
##
# IPv6 address format a:b:c:d:e:f:g:h
Regex_8Hex = /\A
(?:[0-9A-Fa-f]{1,4}:){7}
[0-9A-Fa-f]{1,4}
\z/x
##
# Compressed IPv6 address format a::b
Regex_CompressedHex = /\A
((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::
((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)
\z/x
##
# IPv4 mapped IPv6 address format a:b:c:d:e:f:w.x.y.z
Regex_6Hex4Dec = /\A
((?:[0-9A-Fa-f]{1,4}:){6,6})
(\d+)\.(\d+)\.(\d+)\.(\d+)
\z/x
##
# Compressed IPv4 mapped IPv6 address format a::b:w.x.y.z
Regex_CompressedHex4Dec = /\A
((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::
((?:[0-9A-Fa-f]{1,4}:)*)
(\d+)\.(\d+)\.(\d+)\.(\d+)
\z/x
##
# IPv6 link local address format fe80:b:c:d:e:f:g:h%em1
Regex_8HexLinkLocal = /\A
[Ff][Ee]80
(?::[0-9A-Fa-f]{1,4}){7}
%[-0-9A-Za-z._~]+
\z/x
##
# Compressed IPv6 link local address format fe80::b%em1
Regex_CompressedHexLinkLocal = /\A
[Ff][Ee]80:
(?:
((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::
((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)
|
:((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)
)?
:[0-9A-Fa-f]{1,4}%[-0-9A-Za-z._~]+
\z/x
##
# A composite IPv6 address Regexp.
Regex = /
(?:#{Regex_8Hex}) |
(?:#{Regex_CompressedHex}) |
(?:#{Regex_6Hex4Dec}) |
(?:#{Regex_CompressedHex4Dec}) |
(?:#{Regex_8HexLinkLocal}) |
(?:#{Regex_CompressedHexLinkLocal})
/x
##
# Creates a new IPv6 address from +arg+ which may be:
#
# IPv6:: returns +arg+.
# String:: +arg+ must match one of the IPv6::Regex* constants
def self.create(arg)
case arg
when IPv6
return arg
when String
address = ''.b
if Regex_8Hex =~ arg
arg.scan(/[0-9A-Fa-f]+/) {|hex| address << [hex.hex].pack('n')}
elsif Regex_CompressedHex =~ arg
prefix = $1
suffix = $2
a1 = ''.b
a2 = ''.b
prefix.scan(/[0-9A-Fa-f]+/) {|hex| a1 << [hex.hex].pack('n')}
suffix.scan(/[0-9A-Fa-f]+/) {|hex| a2 << [hex.hex].pack('n')}
omitlen = 16 - a1.length - a2.length
address << a1 << "\0" * omitlen << a2
elsif Regex_6Hex4Dec =~ arg
prefix, a, b, c, d = $1, $2.to_i, $3.to_i, $4.to_i, $5.to_i
if (0..255) === a && (0..255) === b && (0..255) === c && (0..255) === d
prefix.scan(/[0-9A-Fa-f]+/) {|hex| address << [hex.hex].pack('n')}
address << [a, b, c, d].pack('CCCC')
else
raise ArgumentError.new("not numeric IPv6 address: " + arg)
end
elsif Regex_CompressedHex4Dec =~ arg
prefix, suffix, a, b, c, d = $1, $2, $3.to_i, $4.to_i, $5.to_i, $6.to_i
if (0..255) === a && (0..255) === b && (0..255) === c && (0..255) === d
a1 = ''.b
a2 = ''.b
prefix.scan(/[0-9A-Fa-f]+/) {|hex| a1 << [hex.hex].pack('n')}
suffix.scan(/[0-9A-Fa-f]+/) {|hex| a2 << [hex.hex].pack('n')}
omitlen = 12 - a1.length - a2.length
address << a1 << "\0" * omitlen << a2 << [a, b, c, d].pack('CCCC')
else
raise ArgumentError.new("not numeric IPv6 address: " + arg)
end
else
raise ArgumentError.new("not numeric IPv6 address: " + arg)
end
return IPv6.new(address)
else
raise ArgumentError.new("cannot interpret as IPv6 address: #{arg.inspect}")
end
end
def initialize(address) # :nodoc:
unless address.kind_of?(String) && address.length == 16
raise ArgumentError.new('IPv6 address must be 16 bytes')
end
@address = address
end
##
# The raw IPv6 address as a String.
attr_reader :address
def to_s # :nodoc:
address = sprintf("%x:%x:%x:%x:%x:%x:%x:%x", *@address.unpack("nnnnnnnn"))
unless address.sub!(/(^|:)0(:0)+(:|$)/, '::')
address.sub!(/(^|:)0(:|$)/, '::')
end
return address
end
def inspect # :nodoc:
return "#<#{self.class} #{self}>"
end
##
# Turns this IPv6 address into a Resolv::DNS::Name.
#--
# ip6.arpa should be searched too. [RFC3152]
def to_name
return DNS::Name.new(
@address.unpack("H32")[0].split(//).reverse + ['ip6', 'arpa'])
end
def ==(other) # :nodoc:
return @address == other.address
end
def eql?(other) # :nodoc:
return self == other
end
def hash # :nodoc:
return @address.hash
end
end
##
# Resolv::MDNS is a one-shot Multicast DNS (mDNS) resolver. It blindly
# makes queries to the mDNS addresses without understanding anything about
# multicast ports.
#
# Information taken form the following places:
#
# * RFC 6762
class MDNS < DNS
##
# Default mDNS Port
Port = 5353
##
# Default IPv4 mDNS address
AddressV4 = '224.0.0.251'
##
# Default IPv6 mDNS address
AddressV6 = 'ff02::fb'
##
# Default mDNS addresses
Addresses = [
[AddressV4, Port],
[AddressV6, Port],
]
##
# Creates a new one-shot Multicast DNS (mDNS) resolver.
#
# +config_info+ can be:
#
# nil::
# Uses the default mDNS addresses
#
# Hash::
# Must contain :nameserver or :nameserver_port like
# Resolv::DNS#initialize.
def initialize(config_info=nil)
if config_info then
super({ nameserver_port: Addresses }.merge(config_info))
else
super(nameserver_port: Addresses)
end
end
##
# Iterates over all IP addresses for +name+ retrieved from the mDNS
# resolver, provided name ends with "local". If the name does not end in
# "local" no records will be returned.
#
# +name+ can be a Resolv::DNS::Name or a String. Retrieved addresses will
# be a Resolv::IPv4 or Resolv::IPv6
def each_address(name)
name = Resolv::DNS::Name.create(name)
return unless name[-1].to_s == 'local'
super(name)
end
def make_udp_requester # :nodoc:
nameserver_port = @config.nameserver_port
Requester::MDNSOneShot.new(*nameserver_port)
end
end
module LOC
##
# A Resolv::LOC::Size
class Size
Regex = /^(\d+\.*\d*)[m]$/
##
# Creates a new LOC::Size from +arg+ which may be:
#
# LOC::Size:: returns +arg+.
# String:: +arg+ must match the LOC::Size::Regex constant
def self.create(arg)
case arg
when Size
return arg
when String
scalar = ''
if Regex =~ arg
scalar = [(($1.to_f*(1e2)).to_i.to_s[0].to_i*(2**4)+(($1.to_f*(1e2)).to_i.to_s.length-1))].pack("C")
else
raise ArgumentError.new("not a properly formed Size string: " + arg)
end
return Size.new(scalar)
else
raise ArgumentError.new("cannot interpret as Size: #{arg.inspect}")
end
end
def initialize(scalar)
@scalar = scalar
end
##
# The raw size
attr_reader :scalar
def to_s # :nodoc:
s = @scalar.unpack("H2").join.to_s
return ((s[0].to_i)*(10**(s[1].to_i-2))).to_s << "m"
end
def inspect # :nodoc:
return "#<#{self.class} #{self}>"
end
def ==(other) # :nodoc:
return @scalar == other.scalar
end
def eql?(other) # :nodoc:
return self == other
end
def hash # :nodoc:
return @scalar.hash
end
end
##
# A Resolv::LOC::Coord
class Coord
Regex = /^(\d+)\s(\d+)\s(\d+\.\d+)\s([NESW])$/
##
# Creates a new LOC::Coord from +arg+ which may be:
#
# LOC::Coord:: returns +arg+.
# String:: +arg+ must match the LOC::Coord::Regex constant
def self.create(arg)
case arg
when Coord
return arg
when String
coordinates = ''
if Regex =~ arg && $1.to_f < 180
m = $~
hemi = (m[4][/[NE]/]) || (m[4][/[SW]/]) ? 1 : -1
coordinates = [ ((m[1].to_i*(36e5)) + (m[2].to_i*(6e4)) +
(m[3].to_f*(1e3))) * hemi+(2**31) ].pack("N")
orientation = m[4][/[NS]/] ? 'lat' : 'lon'
else
raise ArgumentError.new("not a properly formed Coord string: " + arg)
end
return Coord.new(coordinates,orientation)
else
raise ArgumentError.new("cannot interpret as Coord: #{arg.inspect}")
end
end
def initialize(coordinates,orientation)
unless coordinates.kind_of?(String)
raise ArgumentError.new("Coord must be a 32bit unsigned integer in hex format: #{coordinates.inspect}")
end
unless orientation.kind_of?(String) && orientation[/^lon$|^lat$/]
raise ArgumentError.new('Coord expects orientation to be a String argument of "lat" or "lon"')
end
@coordinates = coordinates
@orientation = orientation
end
##
# The raw coordinates
attr_reader :coordinates
## The orientation of the hemisphere as 'lat' or 'lon'
attr_reader :orientation
def to_s # :nodoc:
c = @coordinates.unpack("N").join.to_i
val = (c - (2**31)).abs
fracsecs = (val % 1e3).to_i.to_s
val = val / 1e3
secs = (val % 60).to_i.to_s
val = val / 60
mins = (val % 60).to_i.to_s
degs = (val / 60).to_i.to_s
posi = (c >= 2**31)
case posi
when true
hemi = @orientation[/^lat$/] ? "N" : "E"
else
hemi = @orientation[/^lon$/] ? "W" : "S"
end
return degs << " " << mins << " " << secs << "." << fracsecs << " " << hemi
end
def inspect # :nodoc:
return "#<#{self.class} #{self}>"
end
def ==(other) # :nodoc:
return @coordinates == other.coordinates
end
def eql?(other) # :nodoc:
return self == other
end
def hash # :nodoc:
return @coordinates.hash
end
end
##
# A Resolv::LOC::Alt
class Alt
Regex = /^([+-]*\d+\.*\d*)[m]$/
##
# Creates a new LOC::Alt from +arg+ which may be:
#
# LOC::Alt:: returns +arg+.
# String:: +arg+ must match the LOC::Alt::Regex constant
def self.create(arg)
case arg
when Alt
return arg
when String
altitude = ''
if Regex =~ arg
altitude = [($1.to_f*(1e2))+(1e7)].pack("N")
else
raise ArgumentError.new("not a properly formed Alt string: " + arg)
end
return Alt.new(altitude)
else
raise ArgumentError.new("cannot interpret as Alt: #{arg.inspect}")
end
end
def initialize(altitude)
@altitude = altitude
end
##
# The raw altitude
attr_reader :altitude
def to_s # :nodoc:
a = @altitude.unpack("N").join.to_i
return ((a.to_f/1e2)-1e5).to_s + "m"
end
def inspect # :nodoc:
return "#<#{self.class} #{self}>"
end
def ==(other) # :nodoc:
return @altitude == other.altitude
end
def eql?(other) # :nodoc:
return self == other
end
def hash # :nodoc:
return @altitude.hash
end
end
end
##
# Default resolver to use for Resolv class methods.
DefaultResolver = self.new
##
# Replaces the resolvers in the default resolver with +new_resolvers+. This
# allows resolvers to be changed for resolv-replace.
def DefaultResolver.replace_resolvers new_resolvers
@resolvers = new_resolvers
end
##
# Address Regexp to use for matching IP addresses.
AddressRegex = /(?:#{IPv4::Regex})|(?:#{IPv6::Regex})/
end
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