slightly better decoding

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

internal/outpost/radius/eap/protocol/eap/decode.go

@@ -0,0 +1,23 @@
+package eap
+
+import (
+	"fmt"
+
+	"goauthentik.io/internal/outpost/radius/eap/protocol"
+)
+
+func EmptyPayload(settings protocol.Settings, t protocol.Type) (protocol.Payload, protocol.Type, error) {
+	for _, cons := range settings.Protocols {
+		np := cons()
+		if np.Type() == t {
+			return np, np.Type(), nil
+		}
+		// If the protocol has an inner protocol, return the original type but the code for the inner protocol
+		if i, ok := np.(protocol.Inner); ok {
+			if ii := i.HasInner(); ii != nil {
+				return np, ii.Type(), nil
+			}
+		}
+	}
+	return nil, protocol.Type(0), fmt.Errorf("unsupported EAP type %d", t)
+}

internal/outpost/radius/eap/protocol/eap/payload.go

@@ -22,6 +22,8 @@ type Payload struct {
 	MsgType    protocol.Type
 	Payload    protocol.Payload
 	RawPayload []byte
+
+	Settings protocol.Settings
 }
 
 func (p *Payload) Type() protocol.Type {
@@ -44,10 +46,12 @@ func (p *Payload) Decode(raw []byte) error {
 	}
 	log.WithField("raw", debug.FormatBytes(raw)).WithField("payload", fmt.Sprintf("%T", p.Payload)).Trace("EAP: decode raw")
 	p.RawPayload = raw[5:]
-	if p.Payload == nil {
-		return nil
+	pp, _, err := EmptyPayload(p.Settings, p.MsgType)
+	if err != nil {
+		return err
 	}
-	err := p.Payload.Decode(raw[5:])
+	p.Payload = pp
+	err = p.Payload.Decode(raw[5:])
 	if err != nil {
 		return err
 	}

internal/outpost/radius/eap/protocol/empty.go

@@ -1,14 +0,0 @@
-package protocol
-
-import "layeh.com/radius"
-
-type EmptyPayload struct {
-	ModifyPacket func(p *radius.Packet) *radius.Packet
-}
-
-func (ep EmptyPayload) Decode(raw []byte) error {
-	return nil
-}
-func (ep EmptyPayload) Encode() ([]byte, error) {
-	return []byte{}, nil
-}