gopenfusion/internal/protocol/cnpeer.go

151 lines
3.2 KiB
Go

package protocol
import (
"encoding/binary"
"fmt"
"io"
"log"
"net"
"time"
"github.com/CPunch/gopenfusion/internal/protocol/pool"
)
const (
USE_E = iota
USE_FE
)
// CNPeer is a simple wrapper for net.Conn connections to send/recv packets over the Fusionfall packet protocol.
type CNPeer struct {
conn net.Conn
eRecv chan *Event
SzID string
E_key []byte
FE_key []byte
AccountID int
PlayerID int32
whichKey int
alive bool
}
func GetTime() uint64 {
return uint64(time.Now().UnixMilli())
}
func NewCNPeer(eRecv chan *Event, conn net.Conn) *CNPeer {
return &CNPeer{
conn: conn,
eRecv: eRecv,
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)
// allocate space for packet size
buf.Write(make([]byte, 4))
// 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
}
}
// prepend the packet size
binary.LittleEndian.PutUint32(buf.Bytes()[:4], uint32(buf.Len()-4))
// encrypt body
switch peer.whichKey {
case USE_E:
EncryptData(buf.Bytes()[4:], peer.E_key)
case USE_FE:
EncryptData(buf.Bytes()[4:], peer.FE_key)
}
// send full packet
log.Printf("Sending %#v, sizeof: %d, buffer: %v", data, buf.Len(), buf.Bytes())
if _, err := peer.conn.Write(buf.Bytes()); err != nil {
return fmt.Errorf("failed to write packet body! %v", err)
}
return nil
}
func (peer *CNPeer) SetActiveKey(whichKey int) {
peer.whichKey = whichKey
}
func (peer *CNPeer) Kill() {
log.Printf("Killing peer %p", peer)
if !peer.alive {
return
}
peer.alive = false
peer.conn.Close()
peer.eRecv <- &Event{Type: EVENT_CLIENT_DISCONNECT, Peer: 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 {
buf := pool.Get()
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 pktID
var pktID uint32
if err := pkt.Decode(&pktID); 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", pktID, sz)
peer.eRecv <- &Event{Type: EVENT_CLIENT_PACKET, Peer: peer, Pkt: buf, PktID: pktID}
return nil
}(); err != nil {
log.Printf("[FATAL] %v", err)
return
}
}
}