diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/net/dnsclient_unix.go | 19 | ||||
| -rw-r--r-- | src/net/dnsclient_unix_test.go | 57 |
2 files changed, 2 insertions, 74 deletions
diff --git a/src/net/dnsclient_unix.go b/src/net/dnsclient_unix.go index fae78ae1b1..21aa91f665 100644 --- a/src/net/dnsclient_unix.go +++ b/src/net/dnsclient_unix.go @@ -30,10 +30,6 @@ const ( // to be used as a useTCP parameter to exchange useTCPOnly = true useUDPOrTCP = false - - // Requested DNS packet size. - // Value taken from https://dnsflagday.net/2020/. - maxDNSPacketSize = 1232 ) var ( @@ -60,19 +56,6 @@ func newRequest(q dnsmessage.Question) (id uint16, udpReq, tcpReq []byte, err er if err := b.Question(q); err != nil { return 0, nil, nil, err } - - // Accept packets up to maxDNSPacketSize. RFC 6891. - if err := b.StartAdditionals(); err != nil { - return 0, nil, nil, err - } - var rh dnsmessage.ResourceHeader - if err := rh.SetEDNS0(maxDNSPacketSize, dnsmessage.RCodeSuccess, false); err != nil { - return 0, nil, nil, err - } - if err := b.OPTResource(rh, dnsmessage.OPTResource{}); err != nil { - return 0, nil, nil, err - } - tcpReq, err = b.Finish() udpReq = tcpReq[2:] l := len(tcpReq) - 2 @@ -99,7 +82,7 @@ func dnsPacketRoundTrip(c Conn, id uint16, query dnsmessage.Question, b []byte) return dnsmessage.Parser{}, dnsmessage.Header{}, err } - b = make([]byte, maxDNSPacketSize) + b = make([]byte, 512) // see RFC 1035 for { n, err := c.Read(b) if err != nil { diff --git a/src/net/dnsclient_unix_test.go b/src/net/dnsclient_unix_test.go index e5f01dba2a..14366eca8c 100644 --- a/src/net/dnsclient_unix_test.go +++ b/src/net/dnsclient_unix_test.go @@ -881,7 +881,7 @@ func (f *fakeDNSPacketConn) Close() error { func TestIgnoreDNSForgeries(t *testing.T) { c, s := Pipe() go func() { - b := make([]byte, maxDNSPacketSize) + b := make([]byte, 512) n, err := s.Read(b) if err != nil { t.Error(err) @@ -2161,58 +2161,3 @@ func TestRootNS(t *testing.T) { t.Errorf("records = [%v]; want [%v]", strings.Join(records, " "), want[0]) } } - -// Test that we advertise support for a larger DNS packet size. -// This isn't a great test as it just tests the dnsmessage package -// against itself. -func TestDNSPacketSize(t *testing.T) { - fake := fakeDNSServer{ - rh: func(_, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { - if len(q.Additionals) == 0 { - t.Error("missing EDNS record") - } else if opt, ok := q.Additionals[0].Body.(*dnsmessage.OPTResource); !ok { - t.Errorf("additional record type %T, expected OPTResource", q.Additionals[0]) - } else if len(opt.Options) != 0 { - t.Errorf("found %d Options, expected none", len(opt.Options)) - } else { - got := int(q.Additionals[0].Header.Class) - t.Logf("EDNS packet size == %d", got) - if got != maxDNSPacketSize { - t.Errorf("EDNS packet size == %d, want %d", got, maxDNSPacketSize) - } - } - - // Hand back a dummy answer to verify that - // LookupIPAddr completes. - r := dnsmessage.Message{ - Header: dnsmessage.Header{ - ID: q.Header.ID, - Response: true, - RCode: dnsmessage.RCodeSuccess, - }, - Questions: q.Questions, - } - if q.Questions[0].Type == dnsmessage.TypeA { - r.Answers = []dnsmessage.Resource{ - { - Header: dnsmessage.ResourceHeader{ - Name: q.Questions[0].Name, - Type: dnsmessage.TypeA, - Class: dnsmessage.ClassINET, - Length: 4, - }, - Body: &dnsmessage.AResource{ - A: TestAddr, - }, - }, - } - } - return r, nil - }, - } - - r := &Resolver{PreferGo: true, Dial: fake.DialContext} - if _, err := r.LookupIPAddr(context.Background(), "go.dev"); err != nil { - t.Errorf("lookup failed: %v", err) - } -} |