1 files changed, 104 insertions, 8 deletions

diff --git a/server/server.go b/server/server.go
index 522cd17..369d5b1 100644
--- a/server/server.go
+++ b/server/server.go
@@ -6,12 +6,20 @@ import (
 	"log"
 	"fmt"
 	"time"
+	"strconv"
+	"strings"
 	"os/signal"
 	"git.citrons.xyz/metronode/classic"
 	"git.citrons.xyz/metronode/phony"
 )
 
 var SoftwareName = "Metronode"
+var supportedExtensions = []string {
+	"ExtEntityPositions",
+}
+var requiredExtensions = []string {
+	"ExtEntityPositions",
+}
 
 type ServerInfo struct {
 	Name string
@@ -227,8 +235,9 @@ func (s *Server) newLevel(info levelInfo) (levelId, *level) {
 	return s.LastId, l
 }
 
-func (s *Server) newPlayer(cl *client, name string) *player {
-	pl := newPlayer(s, cl, name)
+func (s *Server) newPlayer(
+		cl *client, name string, ext map[string]bool) *player {
+	pl := newPlayer(s, cl, name, ext)
 	s.players[name] = pl
 	return pl
 }
@@ -280,7 +289,8 @@ func (s *Server) kick(playerName string, reason string) bool {
 }
 
 func (s *Server) NewPlayer(
-		from phony.Actor, cl *client, name string, reply func(*player)) {
+		from phony.Actor, cl *client, name string, ext map[string]bool,
+		reply func(*player)) {
 	s.Act(from, func() {
 		banReason, ok := s.worldState.Banned[name]
 		if ok {
@@ -293,12 +303,12 @@ func (s *Server) NewPlayer(
 			s.players[name].Act(s, func() {
 				s.players[name].kick("Replaced by new connection")
 				s.Act(s.players[name], func() {
-					s.newPlayer(cl, name)
+					s.newPlayer(cl, name, ext)
 					s.GetPlayer(from, name, reply)
 				})
 			})
 		} else {
-			s.newPlayer(cl, name)
+			s.newPlayer(cl, name, ext)
 			s.GetPlayer(from, name, reply)
 		}
 	})
@@ -347,6 +357,7 @@ type client struct {
 	conn net.Conn
 	username string
 	player *player
+	extensions map[string]bool
 }
 
 func newClient(server *Server, srvInfo ServerInfo, conn net.Conn) *client {
@@ -364,7 +375,9 @@ func (cl *client) performHandshake(conn net.Conn, srvInfo ServerInfo) {
 	cl.conn = conn
 	conn.SetDeadline(time.Now().Add(10 * time.Second))
 
-	packet, err := classic.SReadPacket(conn)
+	var ext = make(map[string]bool)
+
+	packet, err := classic.SReadPacket(conn, ext)
 	if cl.handleError(err) != nil {
 		return
 	}
@@ -377,6 +390,11 @@ func (cl *client) performHandshake(conn net.Conn, srvInfo ServerInfo) {
 			)
 		}
 		cl.username = classic.UnpadString(pid.Username)
+		if pid.Ext == classic.UseCpe {
+			if !cl.cpeHandshake(conn, ext) {
+				return
+			}
+		}
 	default:
 		cl.disconnect("Expected handshake")
 		return
@@ -385,6 +403,7 @@ func (cl *client) performHandshake(conn net.Conn, srvInfo ServerInfo) {
 		cl.disconnect("Invalid player name")
 		return
 	}
+
 	err = classic.WritePacket(conn, &classic.ServerId {
 		Version: 7,
 		ServerName: classic.PadString(srvInfo.Name),
@@ -393,16 +412,93 @@ func (cl *client) performHandshake(conn net.Conn, srvInfo ServerInfo) {
 	if cl.handleError(err) != nil {
 		return
 	}
-	cl.server.NewPlayer(cl, cl, cl.username, func(pl *player) {
+	cl.server.NewPlayer(cl, cl, cl.username, ext, func(pl *player) {
 		cl.player = pl
 	})
 
 	conn.SetDeadline(time.Time{})
 }
 
+func (cl *client) cpeHandshake(conn net.Conn, ext map[string]bool) bool {
+	var (packet classic.Packet; err error)
+	err = classic.WritePacket(conn, &classic.ExtInfo {
+		AppName: classic.PadString(SoftwareName),
+		ExtensionCount: int16(len(supportedExtensions)),
+	})
+	if cl.handleError(err) != nil {
+		return false
+	}
+	for _, extString := range supportedExtensions {
+		var (name string; version = 1)
+		split := strings.Split(extString, ".")
+		name = split[0]
+		if len(split) > 1 {
+			version, err = strconv.Atoi(split[1])
+			if err != nil {
+				panic(err)
+			}
+		}
+		err = classic.WritePacket(conn, &classic.ExtEntry {
+			ExtName: classic.PadString(name),
+			Version: int32(version),
+		})
+		if cl.handleError(err) != nil {
+			return false
+		}
+	}
+	packet, err = classic.SReadPacket(conn, ext)
+	if cl.handleError(err) != nil {
+		return false
+	}
+	var count int
+	switch info := packet.(type) {
+	case *classic.ExtInfo:
+		log.Printf(
+			"%s is connecting via '%s' client with %d extensions",
+			cl.username, info.AppName, info.ExtensionCount,
+		)
+		count = int(info.ExtensionCount)
+	default:
+		cl.disconnect("Expected ExtInfo")
+		return false
+	}
+	for i := 0; i < count; i++ {
+		var extString string
+		packet, err = classic.SReadPacket(conn, ext)
+		if cl.handleError(err) != nil {
+			return false
+		}
+		switch entry := packet.(type) {
+		case *classic.ExtEntry:
+			extString = classic.UnpadString(entry.ExtName)
+			if entry.Version != 1 {
+				extString += "." + strconv.Itoa(int(entry.Version))
+			}
+		default:
+			cl.disconnect("Expected ExtEntry")
+			return false
+		}
+		ext[extString] = true
+	}
+	var extList []string
+	for extString := range ext {
+		extList = append(extList, extString)
+	}
+	log.Printf(
+		"%s has extensions: %s", cl.username, strings.Join(extList, ", "),
+	)
+	for _, req := range requiredExtensions {
+		if !ext[req] {
+			cl.disconnect("Missing required extension: " + req)
+		}
+	}
+	cl.extensions = ext
+	return true
+}
+
 func (cl *client) readPackets(conn net.Conn) {
 	for {
-		packet, err := classic.SReadPacket(conn)
+		packet, err := classic.SReadPacket(conn, cl.extensions)
 		cl.Act(nil, func() {
 			if cl.handleError(err) != nil {
 				return