package dnsx import ( "strings" "testing" "github.com/miekg/dns" ) func TestDNSEncoder(t *testing.T) { t.Run("encode A", func(t *testing.T) { e := &DNSEncoderMiekg{} data, err := e.Encode("x.org", dns.TypeA, false) if err != nil { t.Fatal(err) } dnsValidateEncodedQueryBytes(t, data, byte(dns.TypeA)) }) t.Run("encode AAAA", func(t *testing.T) { e := &DNSEncoderMiekg{} data, err := e.Encode("x.org", dns.TypeAAAA, false) if err != nil { t.Fatal(err) } dnsValidateEncodedQueryBytes(t, data, byte(dns.TypeA)) }) t.Run("encode padding", func(t *testing.T) { // The purpose of this unit test is to make sure that for a wide // array of values we obtain the right query size. getquerylen := func(domainlen int, padding bool) int { e := &DNSEncoderMiekg{} data, err := e.Encode( // This is not a valid name because it ends up being way // longer than 255 octets. However, the library is allowing // us to generate such name and we are not going to send // it on the wire. Also, we check below that the query that // we generate is long enough, so we should be good. dns.Fqdn(strings.Repeat("x.", domainlen)), dns.TypeA, padding, ) if err != nil { t.Fatal(err) } return len(data) } for domainlen := 1; domainlen <= 4000; domainlen++ { vanillalen := getquerylen(domainlen, false) paddedlen := getquerylen(domainlen, true) if vanillalen < domainlen { t.Fatal("vanillalen is smaller than domainlen") } if (paddedlen % dnsPaddingDesiredBlockSize) != 0 { t.Fatal("paddedlen is not a multiple of PaddingDesiredBlockSize") } if paddedlen < vanillalen { t.Fatal("paddedlen is smaller than vanillalen") } } }) } // dnsValidateEncodedQueryBytes validates the query serialized in data // for the given query type qtype (e.g., dns.TypeAAAA). func dnsValidateEncodedQueryBytes(t *testing.T, data []byte, qtype byte) { // skipping over the query ID if data[2] != 1 { t.Fatal("FLAGS should only have RD set") } if data[3] != 0 { t.Fatal("RA|Z|Rcode should be zero") } if data[4] != 0 || data[5] != 1 { t.Fatal("QCOUNT high should be one") } if data[6] != 0 || data[7] != 0 { t.Fatal("ANCOUNT should be zero") } if data[8] != 0 || data[9] != 0 { t.Fatal("NSCOUNT should be zero") } if data[10] != 0 || data[11] != 0 { t.Fatal("ARCOUNT should be zero") } t.Log(data[12]) if data[12] != 1 || data[13] != byte('x') { t.Fatal("The name does not contain 1:x") } if data[14] != 3 || data[15] != byte('o') || data[16] != byte('r') || data[17] != byte('g') { t.Fatal("The name does not contain 3:org") } if data[18] != 0 { t.Fatal("The name does not terminate where expected") } if data[19] != 0 && data[20] != qtype { t.Fatal("The query is not for the expected type") } if data[21] != 0 && data[22] != 1 { t.Fatal("The query is not IN") } }