require 'test/unit' require 'resolv' require 'socket' class TestResolvDNS < Test::Unit::TestCase def setup @save_do_not_reverse_lookup = BasicSocket.do_not_reverse_lookup BasicSocket.do_not_reverse_lookup = true end def teardown BasicSocket.do_not_reverse_lookup = @save_do_not_reverse_lookup end def with_udp(host, port) u = UDPSocket.new begin u.bind(host, port) yield u ensure u.close end end def test_query_ipv4_address with_udp('127.0.0.1', 0) {|u| _, server_port, _, server_address = u.addr begin th = Thread.new { Resolv::DNS.open(:nameserver_port => [[server_address, server_port]]) {|dns| dns.getresources("foo.example.org", Resolv::DNS::Resource::IN::A) } } msg, (af, client_port, _, client_address) = u.recvfrom(4096) id, word2, qdcount, ancount, nscount, arcount = msg.unpack("nnnnnn") qr = (word2 & 0x8000) >> 15 opcode = (word2 & 0x7800) >> 11 aa = (word2 & 0x0400) >> 10 tc = (word2 & 0x0200) >> 9 rd = (word2 & 0x0100) >> 8 ra = (word2 & 0x0080) >> 7 z = (word2 & 0x0070) >> 4 rcode = word2 & 0x000f rest = msg[12..-1] assert_equal(0, qr) # 0:query 1:response assert_equal(0, opcode) # 0:QUERY 1:IQUERY 2:STATUS assert_equal(0, aa) # Authoritative Answer assert_equal(0, tc) # TrunCation assert_equal(1, rd) # Recursion Desired assert_equal(0, ra) # Recursion Available assert_equal(0, z) # Reserved for future use assert_equal(0, rcode) # 0:No-error 1:Format-error 2:Server-failure 3:Name-Error 4:Not-Implemented 5:Refused assert_equal(1, qdcount) # number of entries in the question section. assert_equal(0, ancount) # number of entries in the answer section. assert_equal(0, nscount) # number of entries in the authority records section. assert_equal(0, arcount) # number of entries in the additional records section. name = [3, "foo", 7, "example", 3, "org", 0].pack("Ca*Ca*Ca*C") assert_operator(rest, :start_with?, name) rest = rest[name.length..-1] assert_equal(4, rest.length) qtype, qclass = rest.unpack("nn") assert_equal(1, qtype) # A assert_equal(1, qtype) # IN id = id qr = 1 opcode = opcode aa = 0 tc = 0 rd = rd ra = 1 z = 0 rcode = 0 qdcount = 0 ancount = 1 nscount = 0 arcount = 0 word2 = (qr << 15) | (opcode << 11) | (aa << 10) | (tc << 9) | (rd << 8) | (ra << 7) | (z << 4) | rcode msg = [id, word2, qdcount, ancount, nscount, arcount].pack("nnnnnn") type = 1 klass = 1 ttl = 3600 rdlength = 4 rdata = [192,0,2,1].pack("CCCC") # 192.0.2.1 (TEST-NET address) RFC 3330 rr = [name, type, klass, ttl, rdlength, rdata].pack("a*nnNna*") msg << rr u.send(msg, 0, client_address, client_port) result = th.value assert_instance_of(Array, result) assert_equal(1, result.length) rr = result[0] assert_instance_of(Resolv::DNS::Resource::IN::A, rr) assert_instance_of(Resolv::IPv4, rr.address) assert_equal("192.0.2.1", rr.address.to_s) assert_equal(3600, rr.ttl) ensure th.join end } end def test_no_server u = UDPSocket.new u.bind("127.0.0.1", 0) _, port, _, host = u.addr u.close # A rase condition here. # Another program may use the port. # But no way to prevent it. Resolv::DNS.open(:nameserver_port => [[host, port]]) {|dns| assert_equal([], dns.getresources("test-no-server.example.org", Resolv::DNS::Resource::IN::A)) } end end