initial commit

processor.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+	"errors"
+	"github.com/renorris/openfsd/protocol"
+	"strings"
+)
+
+// ProcessorResult represents the result of a handler function
+type ProcessorResult struct {
+	Replies          []string
+	Mail             []Mail
+	ShouldDisconnect bool
+}
+
+func NewProcessorResult() *ProcessorResult {
+	return &ProcessorResult{
+		Replies:          nil,
+		Mail:             nil,
+		ShouldDisconnect: false,
+	}
+}
+
+// Disconnect sets the flag to disconnect the client
+func (r *ProcessorResult) Disconnect(flag bool) {
+	r.ShouldDisconnect = flag
+}
+
+// AddReply adds a packet to send back to the client
+func (r *ProcessorResult) AddReply(packet string) {
+	if r.Replies == nil {
+		r.Replies = make([]string, 0)
+	}
+	r.Replies = append(r.Replies, packet)
+}
+
+// AddMail adds mail to be sent to other clients
+func (r *ProcessorResult) AddMail(mail Mail) {
+	if r.Mail == nil {
+		r.Mail = make([]Mail, 0)
+	}
+	r.Mail = append(r.Mail, mail)
+}
+
+// Processor represents a function to process an incoming FSD packet
+type Processor func(client *FSDClient, rawPacket string) *ProcessorResult
+
+// InvalidPacketError means the packet was not recognized by the parser
+func newInvalidPacketError() error {
+	return errors.New("Invalid packet")
+}
+
+var (
+	InvalidPacketError = newInvalidPacketError()
+)
+
+func GetProcessor(rawPacket string) (Processor, error) {
+	rawPacket = strings.TrimSuffix(rawPacket, "\r\n")
+	if len(rawPacket) < 3 {
+		return nil, InvalidPacketError
+	}
+
+	fields := strings.Split(rawPacket, protocol.Delimeter)
+
+	switch rawPacket[0] {
+	case '^':
+		return FastPilotPositionProcessor, nil
+	case '@':
+		return PilotPositionProcessor, nil
+	case '#', '$':
+		pduID := rawPacket[0:3]
+		switch pduID {
+		case "$CQ":
+			return ClientQueryProcessor, nil
+		case "$CR":
+			return ClientQueryResponseProcessor, nil
+		case "#SL":
+			return FastPilotPositionProcessor, nil
+		case "#ST":
+			return FastPilotPositionProcessor, nil
+		case "$AX":
+			// TODO: implement METAR request
+		case "$PI":
+			return PingProcessor, nil
+		case "$ZC":
+			return AuthChallengeProcessor, nil
+		case "$ZR":
+			return AuthChallengeResponseProcessor, nil
+		case "$!!":
+			return KillRequestProcessor, nil
+		case "#DP":
+			return DeletePilotProcessor, nil
+		case "#SB":
+			if len(fields) < 3 {
+				return nil, InvalidPacketError
+			}
+			if fields[2] == "PIR" {
+				return PlaneInfoRequestProcessor, nil
+			}
+			if fields[2] == "PI" && len(fields) > 3 && fields[3] == "GEN" {
+				return PlaneInfoResponseProcessor, nil
+			}
+		case "#TM":
+			if len(fields) > 3 {
+				return nil, InvalidPacketError
+			}
+			switch fields[1] {
+			case "*":
+				return BroadcastMessageProcessor, nil
+			case "*S":
+				return WallopMessageProcessor, nil
+			default:
+				if len(fields[1]) > 0 && fields[1][0:1] == "@" {
+					return RadioMessageProcessor, nil
+				} else {
+					return DirectMessageProcessor, nil
+				}
+			}
+		}
+	}
+
+	return nil, InvalidPacketError
+}