WIP: middleware/dnstap (#711)

middleware/dnstap add

vendor/github.com/farsightsec/golang-framestream/Control.go

@@ -0,0 +1,156 @@
+package framestream
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/binary"
+	"io"
+)
+
+const CONTROL_ACCEPT = 0x01
+const CONTROL_START = 0x02
+const CONTROL_STOP = 0x03
+const CONTROL_READY = 0x04
+const CONTROL_FINISH = 0x05
+
+const CONTROL_FIELD_CONTENT_TYPE = 0x01
+
+type ControlFrame struct {
+	ControlType  uint32
+	ContentTypes [][]byte
+}
+
+var ControlStart = ControlFrame{ControlType: CONTROL_START}
+var ControlStop = ControlFrame{ControlType: CONTROL_STOP}
+var ControlReady = ControlFrame{ControlType: CONTROL_READY}
+var ControlAccept = ControlFrame{ControlType: CONTROL_ACCEPT}
+var ControlFinish = ControlFrame{ControlType: CONTROL_FINISH}
+
+func (c *ControlFrame) Encode(w io.Writer) (err error) {
+	var buf bytes.Buffer
+	err = binary.Write(&buf, binary.BigEndian, c.ControlType)
+	if err != nil {
+		return
+	}
+	for _, ctype := range c.ContentTypes {
+		err = binary.Write(&buf, binary.BigEndian, uint32(CONTROL_FIELD_CONTENT_TYPE))
+		if err != nil {
+			return
+		}
+
+		err = binary.Write(&buf, binary.BigEndian, uint32(len(ctype)))
+		if err != nil {
+			return
+		}
+
+		_, err = buf.Write(ctype)
+		if err != nil {
+			return
+		}
+	}
+
+	err = binary.Write(w, binary.BigEndian, uint32(0))
+	if err != nil {
+		return
+	}
+	err = binary.Write(w, binary.BigEndian, uint32(buf.Len()))
+	if err != nil {
+		return
+	}
+	_, err = buf.WriteTo(w)
+	return
+}
+
+func (c *ControlFrame) EncodeFlush(w *bufio.Writer) error {
+	if err := c.Encode(w); err != nil {
+		return err
+	}
+	return w.Flush()
+}
+
+func (c *ControlFrame) Decode(r io.Reader) (err error) {
+	var cflen uint32
+	err = binary.Read(r, binary.BigEndian, &cflen)
+	if err != nil {
+		return
+	}
+
+	err = binary.Read(r, binary.BigEndian, &c.ControlType)
+	if err != nil {
+		return
+	}
+
+	cflen -= 4
+	if cflen > 0 {
+		cfields := make([]byte, int(cflen))
+		_, err = io.ReadFull(r, cfields)
+		if err != nil {
+			return
+		}
+
+		for len(cfields) > 8 {
+			cftype := binary.BigEndian.Uint32(cfields[:4])
+			cfields = cfields[4:]
+			if cftype != CONTROL_FIELD_CONTENT_TYPE {
+				return ErrDecode
+			}
+
+			cflen := int(binary.BigEndian.Uint32(cfields[:4]))
+			cfields = cfields[4:]
+			if cflen > len(cfields) {
+				return ErrDecode
+			}
+
+			c.ContentTypes = append(c.ContentTypes, cfields[:cflen])
+			cfields = cfields[cflen:]
+		}
+
+		if len(cfields) > 0 {
+			return ErrDecode
+		}
+	}
+	return
+}
+
+func (c *ControlFrame) DecodeEscape(r io.Reader) error {
+	var zero uint32
+	err := binary.Read(r, binary.BigEndian, &zero)
+	if err != nil {
+		return err
+	}
+	if zero != 0 {
+		return ErrDecode
+	}
+	return c.Decode(r)
+}
+
+func (c *ControlFrame) DecodeTypeEscape(r io.Reader, ctype uint32) error {
+	err := c.DecodeEscape(r)
+	if err != nil {
+		return err
+	}
+
+	if ctype != c.ControlType {
+		return ErrDecode
+	}
+
+	return nil
+}
+
+func (c *ControlFrame) MatchContentType(ctype []byte) bool {
+	if ctype == nil {
+		return true
+	}
+	for _, cfctype := range c.ContentTypes {
+		if bytes.Compare(ctype, cfctype) == 0 {
+			return true
+		}
+	}
+	return false
+}
+
+func (c *ControlFrame) SetContentType(ctype []byte) {
+	if ctype != nil {
+		c.ContentTypes = [][]byte{ctype}
+	}
+}