protocol: added CNPeer

- moved Peer from the server package to the protocol package, it was also renamed to CNPeer as most fusionfall specific constants in the client use the 'CN' prefix.

protocol/cnpeer.go

@@ -0,0 +1,148 @@
+package protocol
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"log"
+	"net"
+
+	"github.com/CPunch/gopenfusion/protocol/pool"
+)
+
+const (
+	USE_E = iota
+	USE_FE
+)
+
+type PeerHandler interface {
+	HandlePacket(client *CNPeer, typeID uint32, pkt Packet) error
+	Disconnect(client *CNPeer)
+}
+
+// CNPeer is a simple wrapper for net.Conn connections to send/recv packets over the Fusionfall packet protocol.
+type CNPeer struct {
+	conn      net.Conn
+	handler   PeerHandler
+	SzID      string
+	E_key     []byte
+	FE_key    []byte
+	AccountID int
+	whichKey  int
+	alive     bool
+}
+
+func NewCNPeer(handler PeerHandler, conn net.Conn) *CNPeer {
+	return &CNPeer{
+		conn:      conn,
+		handler:   handler,
+		SzID:      "",
+		E_key:     []byte(DEFAULT_KEY),
+		FE_key:    nil,
+		AccountID: -1,
+		whichKey:  USE_E,
+		alive:     true,
+	}
+}
+
+func (peer *CNPeer) Send(typeID uint32, data ...interface{}) error {
+	// grab buffer from pool
+	buf := pool.Get()
+	defer pool.Put(buf)
+
+	// body start
+	pkt := NewPacket(buf)
+
+	// encode type id
+	if err := pkt.Encode(typeID); err != nil {
+		return err
+	}
+
+	// encode data
+	for _, trailer := range data {
+		if err := pkt.Encode(trailer); err != nil {
+			return err
+		}
+	}
+
+	// encrypt body
+	switch peer.whichKey {
+	case USE_E:
+		EncryptData(buf.Bytes(), peer.E_key)
+	case USE_FE:
+		EncryptData(buf.Bytes(), peer.FE_key)
+	}
+
+	// write packet size
+	if err := binary.Write(peer.conn, binary.LittleEndian, uint32(buf.Len())); err != nil {
+		return err
+	}
+
+	// write packet body
+	log.Printf("Sending %#v, sizeof: %d", data, buf.Len())
+	if _, err := peer.conn.Write(buf.Bytes()); err != nil {
+		return fmt.Errorf("[FATAL] failed to write packet body! %v", err)
+	}
+
+	return nil
+}
+
+func (peer *CNPeer) Kill() {
+	if !peer.alive {
+		return
+	}
+
+	peer.alive = false
+	peer.conn.Close()
+	peer.handler.Disconnect(peer)
+}
+
+// meant to be invoked as a goroutine
+func (peer *CNPeer) Handler() {
+	defer peer.Kill()
+
+	for {
+		// read packet size, the goroutine spends most of it's time parked here
+		var sz uint32
+		if err := binary.Read(peer.conn, binary.LittleEndian, &sz); err != nil {
+			log.Printf("[FATAL] failed to read packet size! %v\n", err)
+			return
+		}
+
+		// client should never send a packet size outside of this range
+		if sz > CN_PACKET_BUFFER_SIZE || sz < 4 {
+			log.Printf("[FATAL] malicious packet size received! %d", sz)
+			return
+		}
+
+		// grab buffer && read packet body
+		if err := func() error { // we wrap this in a closure so we can easily defer the buffer return to pool
+			buf := pool.Get()
+			defer pool.Put(buf)
+			if _, err := buf.ReadFrom(io.LimitReader(peer.conn, int64(sz))); err != nil {
+				return fmt.Errorf("failed to read packet body! %v", err)
+			}
+
+			// decrypt
+			DecryptData(buf.Bytes(), peer.E_key)
+			pkt := NewPacket(buf)
+
+			// create packet && read typeID
+			var typeID uint32
+			if err := pkt.Decode(&typeID); err != nil {
+				return fmt.Errorf("failed to read packet type! %v", err)
+			}
+
+			// dispatch packet
+			log.Printf("Got packet ID: %x, with a sizeof: %d\n", typeID, sz)
+			if err := peer.handler.HandlePacket(peer, typeID, pkt); err != nil {
+				return err
+			}
+
+			return nil
+		}(); err != nil {
+			log.Printf("[FATAL] %v", err)
+			return
+		}
+	}
+}