rewrote how packing/unpacking is handled

rvpn/packer/packer.go

@@ -5,11 +5,13 @@ import (
 	"fmt"
 	"net"
 	"strconv"
+	"strings"
 )
 
 const (
-	packerV1 byte = 255 - 1
+	_             = iota // skip the iota value of 0
-	packerV2 byte = 255 - 2
+	packerV1 byte = 255 - iota
+	packerV2
 )
 
 //Packer -- contains both header and data
@@ -26,121 +28,95 @@ func NewPacker() (p *Packer) {
 	return
 }
 
+func splitHeader(header []byte, names []string) (map[string]string, error) {
+	parts := strings.Split(string(header), ",")
+	if p, n := len(parts), len(names); p > n {
+		return nil, fmt.Errorf("Header contains %d extra fields", p-n)
+	} else if p < n {
+		return nil, fmt.Errorf("Header missing fields %q", names[p:])
+	}
+
+	result := make(map[string]string, len(names))
+	for ind, key := range names {
+		result[key] = parts[ind]
+	}
+	return result, nil
+}
+
 //ReadMessage -
-func ReadMessage(b []byte) (p *Packer, err error) {
+func ReadMessage(b []byte) (*Packer, error) {
 	fmt.Println("ReadMessage")
-	var pos int
 
-	err = nil
+	// Detect protocol in use
-	// detect protocol in use
 	if b[0] == packerV1 {
-		p = NewPacker()
+		// Separate the header and body using the header length in the second byte.
+		p := NewPacker()
+		header := b[2 : b[1]+2]
+		data := b[b[1]+2:]
 
-		// Handle Header Length
+		// Handle the different parts of the header.
-		pos = pos + 1
+		parts, err := splitHeader(header, []string{"address family", "address", "port", "data length", "service"})
-		p.Header.HeaderLen = b[pos]
+		if err != nil {
-
-		//handle address family
-		pos = pos + 1
-		end := bytes.IndexAny(b[pos:], ",")
-		if end == -1 {
-			err = fmt.Errorf("missing , while parsing address family")
 			return nil, err
 		}
 
-		bAddrFamily := b[pos : pos+end]
+		if familyText := parts["address family"]; familyText == addressFamilyText[FamilyIPv4] {
-		if bytes.ContainsAny(bAddrFamily, addressFamilyText[FamilyIPv4]) {
 			p.Header.family = FamilyIPv4
-		} else if bytes.ContainsAny(bAddrFamily, addressFamilyText[FamilyIPv6]) {
+		} else if familyText == addressFamilyText[FamilyIPv6] {
 			p.Header.family = FamilyIPv6
 		} else {
-			err = fmt.Errorf("Address family not supported %d", bAddrFamily)
+			return nil, fmt.Errorf("Address family %q not supported", familyText)
 		}
 
-		//handle address
+		p.Header.address = net.ParseIP(parts["address"])
-		pos = pos + end + 1
+		if p.Header.address == nil {
-		end = bytes.IndexAny(b[pos:], ",")
+			return nil, fmt.Errorf("Invalid network address %q", parts["address"])
-		if end == -1 {
+		} else if p.Header.Family() == FamilyIPv4 && p.Header.address.To4() == nil {
-			err = fmt.Errorf("missing , while parsing address")
+			return nil, fmt.Errorf("Address %q is not in address family %s", parts["address"], p.Header.FamilyText())
-			return nil, err
-		}
-		p.Header.address = net.ParseIP(string(b[pos : pos+end]))
-
-		//handle import
-		pos = pos + end + 1
-		end = bytes.IndexAny(b[pos:], ",")
-		if end == -1 {
-			err = fmt.Errorf("missing , while parsing address")
-			return nil, err
 		}
 
-		p.Header.Port, err = strconv.Atoi(string(b[pos : pos+end]))
+		//handle port
-		if err != nil {
+		if port, err := strconv.Atoi(parts["port"]); err != nil {
-			err = fmt.Errorf("error converting port %s", err)
+			return nil, fmt.Errorf("Error converting port %q: %v", parts["port"], err)
+		} else if port <= 0 || port > 65535 {
+			return nil, fmt.Errorf("Port %d out of range", port)
+		} else {
+			p.Header.Port = port
 		}
 
 		//handle data length
-		pos = pos + end + 1
+		if dataLen, err := strconv.Atoi(parts["data length"]); err != nil {
-		end = bytes.IndexAny(b[pos:], ",")
+			return nil, fmt.Errorf("Error converting data length %q: %v", parts["data length"], err)
-		if end == -1 {
+		} else if dataLen != len(data) {
-			err = fmt.Errorf("missing , while parsing address")
+			return nil, fmt.Errorf("Data length %d doesn't match received length %d", dataLen, len(data))
-			return nil, err
-		}
-
-		p.Data.DataLen, err = strconv.Atoi(string(b[pos : pos+end]))
-		if err != nil {
-			err = fmt.Errorf("error converting data length %s", err)
 		}
 
 		//handle Service
-		pos = pos + end + 1
+		p.Header.Service = parts["service"]
-		end = pos + int(p.Header.HeaderLen)
-		p.Header.Service = string(b[pos : p.Header.HeaderLen+2])
 
 		//handle payload
-		pos = int(p.Header.HeaderLen + 2)
+		p.Data.AppendBytes(data)
-		p.Data.AppendBytes(b[pos:])
+		return p, nil
-
-	} else {
-		err = fmt.Errorf("Version %d not supported", b[0:0])
 	}
 
-	return
+	return nil, fmt.Errorf("Version %d not supported", 255-b[0])
-
 }
 
 //PackV1 -- Outputs version 1 of packer
-func (p *Packer) PackV1() (b bytes.Buffer) {
+func (p *Packer) PackV1() bytes.Buffer {
-	version := packerV1
+	header := strings.Join([]string{
-
+		p.Header.FamilyText(),
-	var headerBuf bytes.Buffer
+		p.Header.AddressString(),
-	headerBuf.WriteString(p.Header.FamilyText())
+		strconv.Itoa(p.Header.Port),
-	headerBuf.WriteString(",")
+		strconv.Itoa(p.Data.DataLen()),
-	headerBuf.Write([]byte(p.Header.Address().String()))
+		p.Header.Service,
-	headerBuf.WriteString(",")
+	}, ",")
-	headerBuf.WriteString(fmt.Sprintf("%d", p.Header.Port))
-	headerBuf.WriteString(",")
-	headerBuf.WriteString(fmt.Sprintf("%d", p.Data.buffer.Len()))
-	headerBuf.WriteString(",")
-	headerBuf.WriteString(p.Header.Service)
-
-	var metaBuf bytes.Buffer
-	metaBuf.WriteByte(version)
-	metaBuf.WriteByte(byte(headerBuf.Len()))
 
 	var buf bytes.Buffer
-	buf.Write(metaBuf.Bytes())
+	buf.WriteByte(packerV1)
-	buf.Write(headerBuf.Bytes())
+	buf.WriteByte(byte(len(header)))
-	buf.Write(p.Data.buffer.Bytes())
+	buf.WriteString(header)
+	buf.Write(p.Data.Data())
 
-	//fmt.Println("header: ", headerBuf.String())
+	return buf
-	//fmt.Println("meta: ", metaBuf)
-	//fmt.Println("Data: ", p.Data.buffer)
-	//fmt.Println("Buffer: ", buf.Bytes())
-	//fmt.Println("Buffer: ", hex.Dump(buf.Bytes()))
-	//fmt.Printf("Buffer %s", buf.Bytes())
-
-	b = buf
-
-	return
 }

rvpn/packer/packer_data.go

@@ -6,14 +6,11 @@ import (
 
 //packerData -- Contains packer data
 type packerData struct {
-	buffer  *bytes.Buffer
+	buffer bytes.Buffer
-	DataLen int
 }
 
-func newPackerData() (p *packerData) {
+func newPackerData() *packerData {
-	p = new(packerData)
+	return new(packerData)
-	p.buffer = new(bytes.Buffer)
-	return
 }
 
 func (p *packerData) AppendString(dataString string) (int, error) {
@@ -28,3 +25,7 @@ func (p *packerData) AppendBytes(dataBytes []byte) (int, error) {
 func (p *packerData) Data() []byte {
 	return p.buffer.Bytes()
 }
+
+func (p *packerData) DataLen() int {
+	return p.buffer.Len()
+}

rvpn/packer/packer_header.go

@@ -13,7 +13,6 @@ type packerHeader struct {
 	address net.IP
 	Port    int
 	Service string
-	HeaderLen byte
 }
 
 //Family -- ENUM for Address Family
@@ -32,7 +31,6 @@ func newPackerHeader() (p *packerHeader) {
 	p.SetAddress("127.0.0.1")
 	p.Port = 65535
 	p.Service = "na"
-	p.HeaderLen = 0
 	return
 }