might actually happen?

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

internal/outpost/radius/eap/packet.go

@@ -0,0 +1,89 @@
+package eap
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+
+	"goauthentik.io/internal/outpost/radius/eap/tls"
+)
+
+type Code uint8
+
+const (
+	CodeRequest  Code = 1
+	CodeResponse Code = 2
+)
+
+type Type uint8
+
+const (
+	TypeIdentity     Type = 1
+	TypeMD5Challenge Type = 4
+	TypeTLS          Type = 13
+)
+
+type Packet struct {
+	code       Code
+	id         uint8
+	length     uint16
+	msgType    Type
+	rawPayload []byte
+	Payload    Payload
+}
+
+type Payload interface {
+	Decode(raw []byte) error
+	Encode() ([]byte, error)
+}
+
+type PayloadWriter struct{}
+
+func emptyPayload(t Type) Payload {
+	switch t {
+	case TypeIdentity:
+		return &IdentityPayload{}
+	case TypeTLS:
+		return &tls.Payload{}
+	}
+	return nil
+}
+
+func Decode(raw []byte) (*Packet, error) {
+	packet := &Packet{}
+	packet.code = Code(raw[0])
+	packet.id = raw[1]
+	packet.length = binary.BigEndian.Uint16(raw[2:])
+	if packet.length != uint16(len(raw)) {
+		return nil, errors.New("mismatched packet length")
+	}
+	if len(raw) > 4 && (packet.code == CodeRequest || packet.code == CodeResponse) {
+		packet.msgType = Type(raw[4])
+	}
+	packet.Payload = emptyPayload(packet.msgType)
+	packet.rawPayload = raw[5:]
+	fmt.Printf("decode raw '% x\n", raw[5:])
+	err := packet.Payload.Decode(raw[5:])
+	if err != nil {
+		return nil, err
+	}
+	return packet, nil
+}
+
+func (p *Packet) Encode() ([]byte, error) {
+	buff := make([]byte, 5)
+	buff[0] = uint8(p.code)
+	buff[1] = uint8(p.id)
+
+	payloadBuffer, err := p.Payload.Encode()
+	if err != nil {
+		return buff, err
+	}
+	binary.BigEndian.PutUint16(buff[2:], uint16(len(payloadBuffer)+5))
+
+	if p.code == CodeRequest || p.code == CodeResponse {
+		buff[4] = uint8(p.msgType)
+	}
+	buff = append(buff, payloadBuffer...)
+	return buff, nil
+}