flesh out data types and start some db access

0x17_authorization_registration_service.go

@@ -1,22 +1,35 @@
 package main
 
 import (
-	"context"
-	"fmt"
+	"errors"
 )
 
-var cipher = "hey wassup"
-
 type AuthorizationRegistrationService struct{}
 
-func (a *AuthorizationRegistrationService) HandleSNAC(ctx context.Context, snac *SNAC) {
+func (a *AuthorizationRegistrationService) HandleSNAC(session *Session, snac *SNAC) error {
+	switch snac.Header.Subtype {
 	// Request MD5 Auth Key
-	if snac.Header.Subtype == 0x06 {
-		fmt.Println("damn it's 0x06")
-		// cipherData := ByteString(cipher) // []byte
+	case 0x06:
+		tlvs, err := UnmarshalTLVs(snac.Data)
+		panicIfError(err)
 
-		// snac := NewSNAC(0x17, 0x07, cipherData)
+		usernameTLV := FindTLV(tlvs, 1)
+		if usernameTLV == nil {
+			return errors.New("missing username TLV")
+		}
 
-		// resp := NewFLAP(2, snac)
+		// Create cipher for this user
+		cipher := "howdy"
+		db.Set("cipher-"+string(usernameTLV.Data), cipher)
+		cipherData := []byte(cipher)
+
+		snac := NewSNAC(0x17, 0x07, cipherData)
+		snacBytes, err := snac.MarshalBinary()
+		panicIfError(err)
+
+		resp := NewFLAP(session, 2, snacBytes)
+		return session.Send(resp)
 	}
+
+	return nil
 }

db.go

@@ -0,0 +1,19 @@
+package main
+
+type DB struct {
+	data map[string]string
+}
+
+func (d *DB) Init() {
+	d.data = make(map[string]string)
+}
+
+func (d *DB) Get(key string) (data string, ok bool) {
+	data, ok = d.data[key]
+	return
+}
+
+func (d *DB) Set(key string, value string) error {
+	d.data[key] = value
+	return nil
+}

flap.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"bytes"
-	"context"
 	"encoding"
 	"encoding/binary"
 	"fmt"
@@ -22,8 +21,7 @@ type FLAP struct {
 	Data   []byte
 }
 
-func NewFLAP(ctx context.Context, channel uint8, data []byte) *FLAP {
-	session := ctx.Value("session").(*Session)
+func NewFLAP(session *Session, channel uint8, data []byte) *FLAP {
 	session.SequenceNumber += 1
 
 	return &FLAP{
@@ -36,6 +34,21 @@ func NewFLAP(ctx context.Context, channel uint8, data []byte) *FLAP {
 	}
 }
 
+func (f *FLAP) MarshalBinary() ([]byte, error) {
+	var buf bytes.Buffer
+	buf.WriteByte(0x2a)
+	binary.Write(&buf, binary.BigEndian, f.Header)
+	n, err := buf.Write(f.Data)
+	if n != int(f.Header.DataLength) {
+		return nil, fmt.Errorf("needed to write %d bytes to buffer but wrote %d", f.Header.DataLength, n)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
 func (f *FLAP) UnmarshalBinary(data []byte) error {
 	buf := bytes.NewBuffer(data)
 	start, err := buf.ReadByte()
@@ -54,17 +67,10 @@ func (f *FLAP) UnmarshalBinary(data []byte) error {
 	return nil
 }
 
-func (f *FLAP) MarshalBinary() ([]byte, error) {
-	var buf bytes.Buffer
-	buf.WriteByte(0x2a)
-	binary.Write(&buf, binary.BigEndian, f.Header)
-	n, err := buf.Write(f.Data)
-	if n != int(f.Header.DataLength) {
-		return nil, fmt.Errorf("needed to write %d bytes to buffer but wrote %d", f.Header.DataLength, n)
-	}
-	if err != nil {
-		return nil, err
-	}
-
-	return buf.Bytes(), nil
+func (f *FLAP) Len() int {
+	return 6 + int(f.Header.DataLength)
+}
+
+func (f *FLAP) String() string {
+	return fmt.Sprintf("FLAP(CH:%d, SEQ:%d):\n%s", f.Header.Channel, f.Header.SequenceNumber, prettyBytes(f.Data))
 }

main.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"context"
 	"fmt"
 	"io"
 	"log"
@@ -10,7 +9,7 @@ import (
 	"os/signal"
 	"syscall"
 
-	"github.com/ghostiam/binstruct"
+	"github.com/pkg/errors"
 )
 
 const (
@@ -20,8 +19,11 @@ const (
 )
 
 var services = make(map[uint16]Service)
+var db *DB = nil
 
 func init() {
+	db = &DB{}
+	db.Init()
 	services[0x17] = &AuthorizationRegistrationService{}
 }
 
@@ -49,29 +51,27 @@ func main() {
 			os.Exit(1)
 		}
 
-		ctx := NewContextWithSession(context.Background(), conn)
+		session := NewSession(conn)
 		log.Printf("Connection from %v", conn.RemoteAddr())
 
-		go handleTCPConnection(ctx, conn)
+		go handleTCPConnection(session, conn)
 	}
 }
 
-func handleTCPConnection(ctx context.Context, conn net.Conn) {
-	defer (func() {
-		if r := recover(); r != nil {
-			log.Println("Error handling message: ", r.(error).Error())
-		}
-		conn.Close()
-		log.Printf("Closed connection to %v", conn.RemoteAddr())
-	})()
+func handleTCPConnection(session *Session, conn net.Conn) {
+	// defer (func() {
+	// 	if err := recover(); err != nil {
+	// 		log.Printf("Error handling message: %+v\n", err.(error))
+	// 	}
+	// 	conn.Close()
+	// 	log.Printf("Closed connection to %v", conn.RemoteAddr())
+	// })()
 
 	buf := make([]byte, 1024)
 	for {
-		session, err := CurrentSession(ctx)
-		panicIfError(err)
 		if !session.GreetedClient {
 			// send a hello
-			hello := NewFLAP(ctx, 1, []byte{0, 0, 0, 1})
+			hello := NewFLAP(session, 1, []byte{0, 0, 0, 1})
 			err := session.Send(hello)
 			panicIfError(err)
 			session.GreetedClient = true
@@ -87,25 +87,47 @@ func handleTCPConnection(ctx context.Context, conn net.Conn) {
 			return
 		}
 
-		fmt.Printf("%v ->\n%s\n\n", conn.RemoteAddr(), prettyBytes(buf[:n]))
+		// Try to parse all of the FLAPs in the buffer if we have enough bytes to
+		// fill a FLAP header
+		for len(buf) >= 6 && buf[0] == 0x2a {
+			dataLength := Word(buf[4:6])
+			flapLength := int(dataLength) + 6
+			if len(buf) < flapLength {
+				log.Printf("not enough data, only %d bytes\n", len(buf))
+				break
+			}
 
-		flap := &FLAP{}
-		binstruct.UnmarshalBE(buf[:n], flap)
-
-		handleMessage(ctx, flap)
+			flap := &FLAP{}
+			if err := flap.UnmarshalBinary(buf[:flapLength]); err != nil {
+				panicIfError(errors.Wrap(err, "could not unmarshal FLAP"))
+			}
+			buf = buf[flapLength:]
+			fmt.Printf("%v ->\n%+v\n", conn.RemoteAddr(), flap)
+			handleMessage(session, flap)
+		}
 	}
 }
 
-func handleMessage(ctx context.Context, flap *FLAP) {
-	if flap.Channel == 1 {
+func handleMessage(session *Session, flap *FLAP) {
+	if flap.Header.Channel == 1 {
 
-	} else if flap.Channel == 2 {
+	} else if flap.Header.Channel == 2 {
 		snac := &SNAC{}
 		err := snac.UnmarshalBinary(flap.Data)
 		panicIfError(err)
 
+		fmt.Printf("%+v\n", snac)
+		if tlvs, err := UnmarshalTLVs(snac.Data); err == nil {
+			for _, tlv := range tlvs {
+				fmt.Printf("%+v\n", tlv)
+			}
+		} else {
+			fmt.Printf("%s\n\n", prettyBytes(snac.Data))
+		}
+
 		if service, ok := services[snac.Header.Family]; ok {
-			service.HandleSNAC(ctx, snac)
+			err = service.HandleSNAC(session, snac)
+			panicIfError(err)
 		}
 	}
 }

service.go

@@ -1,9 +1,5 @@
 package main
 
-import (
-	"context"
-)
-
 type Service interface {
-	HandleSNAC(context.Context, *SNAC)
+	HandleSNAC(*Session, *SNAC) error
 }

session.go

@@ -5,6 +5,8 @@ import (
 	"encoding"
 	"fmt"
 	"net"
+
+	"github.com/pkg/errors"
 )
 
 type sessionKey string
@@ -37,20 +39,20 @@ func NewContextWithSession(ctx context.Context, conn net.Conn) context.Context {
 }
 
 func CurrentSession(ctx context.Context) (session *Session, err error) {
-	session, ok := ctx.Value(currentSession).(*Session)
-	if !ok {
-		return nil, fmt.Errorf("no session in context")
+	s := ctx.Value(currentSession)
+	if s == nil {
+		return nil, errors.New("no session in context")
 	}
-	return
+	return s.(*Session), nil
 }
 
 func (s *Session) Send(m encoding.BinaryMarshaler) error {
 	bytes, err := m.MarshalBinary()
 	if err != nil {
-		return err
+		return errors.Wrap(err, "could not marshal message")
 	}
 
 	fmt.Printf("-> %v\n%s\n\n", s.Conn.RemoteAddr(), prettyBytes(bytes))
 	_, err = s.Conn.Write(bytes)
-	return err
+	return errors.Wrap(err, "could not write to client connection")
 }

snac.go

@@ -2,15 +2,19 @@ package main
 
 import (
 	"bytes"
+	"encoding"
 	"encoding/binary"
 	"fmt"
 )
 
+var _ encoding.BinaryUnmarshaler = &SNAC{}
+var _ encoding.BinaryMarshaler = &SNAC{}
+
 type SNACHeader struct {
 	Family    uint16
 	Subtype   uint16
 	Flags     uint16
-	RequestID uint16
+	RequestID uint32
 }
 
 type SNAC struct {
@@ -19,6 +23,9 @@ type SNAC struct {
 }
 
 func NewSNAC(family uint16, subtype uint16, data []byte) *SNAC {
+	d := make([]byte, 0, len(data))
+	copy(d, data)
+
 	return &SNAC{
 		Header: SNACHeader{
 			Family:    family,
@@ -26,7 +33,7 @@ func NewSNAC(family uint16, subtype uint16, data []byte) *SNAC {
 			Flags:     0,
 			RequestID: 0,
 		},
-		Data: data,
+		Data: d,
 	}
 }
 
@@ -47,12 +54,16 @@ func (s *SNAC) MarshalBinary() ([]byte, error) {
 
 func (s *SNAC) UnmarshalBinary(data []byte) error {
 	buf := bytes.NewBuffer(data)
-
-	if err := binary.Read(buf, binary.BigEndian, &s.Header); s != nil {
+	if err := binary.Read(buf, binary.BigEndian, &s.Header); err != nil {
 		return err
 	}
 
-	s.Data = buf.Bytes()
+	s.Data = make([]byte, buf.Len())
+	copy(s.Data, buf.Bytes())
 
 	return nil
 }
+
+func (s *SNAC) String() string {
+	return fmt.Sprintf("SNAC(%#x, %#x)", s.Header.Family, s.Header.Subtype)
+}

tlv.go

@@ -0,0 +1,114 @@
+package main
+
+import (
+	"encoding"
+	"encoding/binary"
+	"fmt"
+	"io"
+
+	"github.com/pkg/errors"
+)
+
+var _ encoding.BinaryUnmarshaler = &TLV{}
+var _ encoding.BinaryMarshaler = &TLV{}
+
+type TLV struct {
+	Type       uint16
+	DataLength uint16
+	Data       []byte
+}
+
+func NewTLV(tlvType uint16, data []byte) *TLV {
+	return &TLV{
+		Type:       tlvType,
+		DataLength: uint16(len(data)),
+		Data:       data,
+	}
+}
+
+func (t *TLV) Len() int {
+	return 4 + int(t.DataLength)
+}
+
+func (t *TLV) MarshalBinary() ([]byte, error) {
+	buf := make([]byte, 4+t.DataLength)
+	binary.BigEndian.PutUint16(buf[:2], t.Type)
+	binary.BigEndian.PutUint16(buf[2:4], t.DataLength)
+	copy(buf[4:], t.Data)
+	return buf, nil
+}
+
+func (t *TLV) UnmarshalBinary(data []byte) error {
+	if len(data) < 4 {
+		return io.ErrUnexpectedEOF
+	}
+	t.Type = Word(data[:2])
+	t.DataLength = Word(data[2:4])
+	if len(data) < 4+int(t.DataLength) {
+		return io.ErrUnexpectedEOF
+	}
+	t.Data = make([]byte, int(t.DataLength))
+	copy(t.Data, data[4:4+int(t.DataLength)])
+	return nil
+}
+
+func (t *TLV) String() string {
+	return fmt.Sprintf("TLV(%#x):\n%s", t.Type, prettyBytes(t.Data))
+}
+
+func UnmarshalTLVs(data []byte) ([]*TLV, error) {
+	tlvs := make([]*TLV, 0)
+	d := make([]byte, len(data))
+	copy(d, data)
+
+	for len(d) > 0 {
+		tlv := &TLV{}
+		if err := tlv.UnmarshalBinary(d); err != nil {
+			return nil, errors.Wrap(err, "enexpected end to unmarshalling TLVs")
+		}
+		tlvs = append(tlvs, tlv)
+		d = d[tlv.Len():]
+	}
+	return tlvs, nil
+}
+
+func FindTLV(tlvs []*TLV, tlvType uint16) *TLV {
+	for _, tlv := range tlvs {
+		if tlv.Type == tlvType {
+			return tlv
+		}
+	}
+	return nil
+}
+
+// type TLVReader struct {
+// 	buf []byte
+// 	pos int
+// }
+
+// func (r *TLVReader) ReadNextTLV() (*TLV, error) {
+// 	if len(r.buf) < 4 {
+// 		return nil, io.ErrUnexpectedEOF
+// 	}
+
+// 	t := &TLV{}
+// 	t.Type = Word(r.buf[r.pos:r.pos+2])
+// 	r.pos = r.pos + 2
+// 	t.DataLength = Word(r.buf[r.pos : r.pos+2])
+// 	r.pos = r.pos + 2
+// 	copy(p[2:4], r.buf[r.pos:r.pos+2])
+// 	r.pos = r.pos + 2
+
+// 	// If there is not enough space to write the expected amount of data, error
+// 	if dataLength > len(p)+4 {
+// 		return 0, io.ErrUnexpectedEOF
+// 	}
+
+// 	n = n + copy(p[4:dataLength], r.buf[r.pos:r.pos+dataLength])
+// 	r.pos = r.pos + dataLength
+// 	return n, nil
+// }
+
+// func NewTLVReader(data []byte) *TLVReader {
+// 	return &TLVReader{buf: data, pos: 0}
+// }

util.go

@@ -23,3 +23,13 @@ func panicIfError(err error) {
 		panic(err)
 	}
 }
+
+func Word(b []byte) uint16 {
+	var _ = b[1]
+	return uint16(b[1]) | uint16(b[0])<<8
+}
+
+func DWord(b []byte) uint32 {
+	var _ = b[3]
+	return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
+}