Refactor: separate packet parsing and connection state

Computing a response to a packet is now separate from unpacking a packet
This commit is contained in:
ChillerDragon 2024-06-22 12:25:29 +08:00
parent 915943ff16
commit 72bf459d79
8 changed files with 158 additions and 172 deletions

View file

@ -36,9 +36,8 @@ func (msg CtrlConnect) Pack() []byte {
)
}
// TODO: no idea if this works
func (msg *CtrlConnect) Unpack(u *packer.Unpacker) {
msg.Token = [4]byte(u.Data())
msg.Token = [4]byte(u.Rest())
}
func (msg *CtrlConnect) Header() *chunk7.ChunkHeader {

View file

@ -39,9 +39,8 @@ func (msg CtrlToken) Pack() []byte {
)
}
// TODO: no idea if this works
func (msg *CtrlToken) Unpack(u *packer.Unpacker) {
msg.Token = [4]byte(u.Data())
msg.Token = [4]byte(u.Rest())
}
func (msg *CtrlToken) Header() *chunk7.ChunkHeader {

61
messages7/snap_single.go Normal file
View file

@ -0,0 +1,61 @@
package messages7
import (
"slices"
"github.com/teeworlds-go/teeworlds/chunk7"
"github.com/teeworlds-go/teeworlds/network7"
"github.com/teeworlds-go/teeworlds/packer"
)
type SnapSingle struct {
ChunkHeader *chunk7.ChunkHeader
GameTick int
DeltaTick int
Crc int
PartSize int
Data []byte
}
func (msg SnapSingle) MsgId() int {
return network7.MsgSysSnapSingle
}
func (msg SnapSingle) MsgType() network7.MsgType {
return network7.TypeNet
}
func (msg SnapSingle) System() bool {
return true
}
func (msg SnapSingle) Vital() bool {
return false
}
func (msg SnapSingle) Pack() []byte {
return slices.Concat(
packer.PackInt(msg.GameTick),
packer.PackInt(msg.DeltaTick),
packer.PackInt(msg.Crc),
packer.PackInt(msg.PartSize),
msg.Data[:],
)
}
func (msg *SnapSingle) Unpack(u *packer.Unpacker) {
msg.GameTick = u.GetInt()
msg.DeltaTick = u.GetInt()
msg.Crc = u.GetInt()
msg.PartSize = u.GetInt()
msg.Data = u.Rest()
}
func (msg *SnapSingle) Header() *chunk7.ChunkHeader {
return msg.ChunkHeader
}
func (msg *SnapSingle) SetHeader(header *chunk7.ChunkHeader) {
msg.ChunkHeader = header
}

View file

@ -39,8 +39,7 @@ func (msg Unknown) System() bool {
}
func (msg Unknown) Vital() bool {
// TODO: check is not ctrl and then unpack Data
panic("not implemented yet")
panic("You are not mean't to pack unknown messages. Use msg.Header().Vital instead.")
}
func (msg Unknown) Pack() []byte {
@ -52,7 +51,10 @@ func (msg *Unknown) Unpack(u *packer.Unpacker) {
}
func (msg *Unknown) Header() *chunk7.ChunkHeader {
return nil
if msg.Type == network7.TypeControl {
return nil
}
return msg.ChunkHeader
}
func (msg *Unknown) SetHeader(header *chunk7.ChunkHeader) {

View file

@ -4,13 +4,9 @@ import (
"bytes"
"fmt"
"os"
"slices"
"github.com/teeworlds-go/huffman"
"github.com/teeworlds-go/teeworlds/chunk7"
"github.com/teeworlds-go/teeworlds/messages7"
"github.com/teeworlds-go/teeworlds/network7"
"github.com/teeworlds-go/teeworlds/packer"
)
type Player struct {
@ -96,19 +92,20 @@ func byteSliceToString(s []byte) string {
return string(s)
}
func (connection *Connection) OnSystemMsg(msg int, chunk chunk7.Chunk, u *packer.Unpacker, result *PacketResult) bool {
if msg == network7.MsgSysMapChange {
func (connection *Connection) OnSystemMsg(msg messages7.NetMessage, response *Packet) bool {
// TODO: is this shadow nasty?
switch msg := msg.(type) {
case *messages7.MapChange:
fmt.Println("got map change")
result.Response.Messages = append(result.Response.Messages, &messages7.Ready{})
} else if msg == network7.MsgSysConReady {
response.Messages = append(response.Messages, &messages7.Ready{})
case *messages7.ConReady:
fmt.Println("got ready")
result.Response.Messages = append(result.Response.Messages, connection.MsgStartInfo())
} else if msg == network7.MsgSysSnapSingle {
// tick := u.GetInt()
// fmt.Printf("got snap single tick=%d\n", tick)
result.Response.Messages = append(result.Response.Messages, &messages7.CtrlKeepAlive{})
} else {
fmt.Printf("unknown system message id=%d data=%x\n", msg, chunk.Data)
response.Messages = append(response.Messages, connection.MsgStartInfo())
case *messages7.SnapSingle:
// fmt.Printf("got snap single tick=%d\n", msg.GameTick)
response.Messages = append(response.Messages, &messages7.CtrlKeepAlive{})
default:
fmt.Printf("unknown system message id=%d payload=%x\n", msg.MsgId(), msg.Pack())
return false
}
return true
@ -123,155 +120,78 @@ func (client *Connection) OnChatMessage(msg *messages7.SvChat) {
fmt.Printf("[chat] <%s> %s\n", name, msg.Message)
}
func (client *Connection) OnMotd(motd string) {
fmt.Printf("[motd] %s\n", motd)
}
func (client *Connection) OnGameMsg(msg int, chunk chunk7.Chunk, u *packer.Unpacker, result *PacketResult) bool {
if msg == network7.MsgGameReadyToEnter {
func (connection *Connection) OnGameMsg(msg messages7.NetMessage, response *Packet) bool {
// TODO: is this shadow nasty?
switch msg := msg.(type) {
case *messages7.ReadyToEnter:
fmt.Println("got ready to enter")
result.Packet.Messages = append(result.Packet.Messages, &messages7.Ready{ChunkHeader: &chunk.Header})
result.Response.Messages = append(result.Response.Messages, &messages7.EnterGame{})
} else if msg == network7.MsgGameSvMotd {
motd := u.GetString()
if motd != "" {
client.OnMotd(motd)
}
} else if msg == network7.MsgGameSvChat {
chat := &messages7.SvChat{ChunkHeader: &chunk.Header}
chat.Unpack(u)
client.OnChatMessage(chat)
result.Packet.Messages = append(result.Packet.Messages, chat)
} else if msg == network7.MsgGameSvClientInfo {
clientId := packer.UnpackInt(chunk.Data[1:])
client.Players[clientId].Info.Unpack(u)
fmt.Printf("got client info id=%d name=%s\n", clientId, client.Players[clientId].Info.Name)
} else {
fmt.Printf("unknown game message id=%d data=%x\n", msg, chunk.Data)
response.Messages = append(response.Messages, &messages7.EnterGame{})
case *messages7.SvMotd:
fmt.Printf("[motd] %s\n", msg.Message)
case *messages7.SvChat:
connection.OnChatMessage(msg)
case *messages7.SvClientInfo:
connection.Players[msg.ClientId].Info = *msg
fmt.Printf("got client info id=%d name=%s\n", msg.ClientId, msg.Name)
default:
fmt.Printf("unknown game message id=%d payload=%x\n", msg.MsgId(), msg.Pack())
return false
}
return true
}
func (client *Connection) OnMessage(chunk chunk7.Chunk, result *PacketResult) bool {
// fmt.Printf("got chunk size=%d data=%v\n", chunk.Header.Size, chunk.Data)
if chunk.Header.Flags.Vital {
client.Ack++
func (connection *Connection) OnMessage(msg messages7.NetMessage, response *Packet) bool {
if msg.Header() == nil {
// this is probably an unknown message
fmt.Printf("warning ignoring msgId=%d because header is nil\n", msg.MsgId())
return false
}
if msg.Header().Flags.Vital {
connection.Ack++
}
u := packer.Unpacker{}
u.Reset(chunk.Data)
msg := u.GetInt()
sys := msg&1 != 0
msg >>= 1
if sys {
return client.OnSystemMsg(msg, chunk, &u, result)
if msg.System() {
return connection.OnSystemMsg(msg, response)
}
return client.OnGameMsg(msg, chunk, &u, result)
return connection.OnGameMsg(msg, response)
}
func (connection *Connection) OnPacketPayload(data []byte, result *PacketResult) (*PacketResult, error) {
chunks := chunk7.UnpackChunks(data)
// Takes a full teeworlds packet as argument
// And returns the response packet from the clients perspective
func (connection *Connection) OnPacket(packet *Packet) *Packet {
response := connection.BuildResponse()
for _, c := range chunks {
if connection.OnMessage(c, result) == false {
unknown := &messages7.Unknown{
Data: slices.Concat(c.Header.Pack(), c.Data),
Type: network7.TypeNet,
}
result.Packet.Messages = append(result.Packet.Messages, unknown)
}
}
return result, nil
}
type PacketResult struct {
// Suggested response that should be sent to the server
// Will be *nil* if no response should be sent
Response *Packet
// Incoming traffic from the server parsed into a Packet struct
Packet *Packet
}
// TODO: there should be a Packet.Unpack()
//
// and it should only do the parsing no state handling or responses
// and Connection.OnPack() should take a Packet instance as parameter
// not raw data
// So ideally it would look like this:
//
// packet := Packet{}
// packet.Unpack(data)
// conn := Connection{}
// result, err := conn.OnPacket(packet)
func (connection *Connection) OnPacket(data []byte) (*PacketResult, error) {
result := &PacketResult{
Response: connection.BuildResponse(),
Packet: &Packet{},
}
result.Packet.Header.Unpack(data[:7])
payload := data[7:]
if result.Packet.Header.Flags.Control {
ctrlMsg := int(payload[0])
fmt.Printf("got ctrl msg %d\n", ctrlMsg)
if ctrlMsg == network7.MsgCtrlToken {
copy(connection.ServerToken[:], payload[1:5])
result.Response.Header.Token = connection.ServerToken
fmt.Printf("got server token %x\n", connection.ServerToken)
result.Packet.Messages = append(result.Packet.Messages, &messages7.CtrlToken{Token: connection.ServerToken})
result.Response.Messages = append(
result.Response.Messages,
if packet.Header.Flags.Control {
msg := packet.Messages[0]
fmt.Printf("got ctrl msg %d\n", msg.MsgId())
// TODO: is this shadow nasty?
switch msg := msg.(type) {
case *messages7.CtrlToken:
fmt.Printf("got server token %x\n", msg.Token)
connection.ServerToken = msg.Token
response.Header.Token = msg.Token
response.Messages = append(
response.Messages,
&messages7.CtrlConnect{
Token: connection.ClientToken,
},
)
} else if ctrlMsg == network7.MsgCtrlAccept {
case *messages7.CtrlAccept:
fmt.Println("got accept")
result.Packet.Messages = append(result.Packet.Messages, &messages7.CtrlAccept{})
// TODO: don't hardcode info
result.Response.Messages = append(result.Response.Messages, &messages7.Info{})
} else if ctrlMsg == network7.MsgCtrlClose {
// TODO: get length from packet header to determine if a reason is set or not
// len(data) -> is 1400 (maxPacketLen)
reason := byteSliceToString(payload)
fmt.Printf("disconnected (%s)\n", reason)
response.Messages = append(response.Messages, &messages7.Info{})
case *messages7.CtrlClose:
fmt.Printf("disconnected (%s)\n", msg.Reason)
os.Exit(0)
} else {
unknown := &messages7.Unknown{
Data: payload,
Type: network7.TypeControl,
}
result.Packet.Messages = append(result.Packet.Messages, unknown)
fmt.Printf("unknown control message: %x\n", data)
default:
fmt.Printf("unknown control message: %d\n", msg.MsgId())
}
if len(result.Response.Messages) == 0 {
return nil, nil
}
return result, nil
return response
}
if result.Packet.Header.Flags.Compression {
huff := huffman.Huffman{}
var err error
payload, err = huff.Decompress(payload)
if err != nil {
fmt.Printf("huffman error: %v\n", err)
return nil, nil
}
for _, msg := range packet.Messages {
connection.OnMessage(msg, response)
}
result, err := connection.OnPacketPayload(payload, result)
return result, err
return response
}

View file

@ -89,6 +89,10 @@ func (packet *Packet) unpackSystem(msgId int, chunk chunk7.Chunk, u *packer.Unpa
msg := &messages7.ConReady{ChunkHeader: &chunk.Header}
msg.Unpack(u)
packet.Messages = append(packet.Messages, msg)
} else if msgId == network7.MsgSysSnapSingle {
msg := &messages7.SnapSingle{ChunkHeader: &chunk.Header}
msg.Unpack(u)
packet.Messages = append(packet.Messages, msg)
} else {
return false
}
@ -98,7 +102,7 @@ func (packet *Packet) unpackSystem(msgId int, chunk chunk7.Chunk, u *packer.Unpa
func (packet *Packet) unpackGame(msgId int, chunk chunk7.Chunk, u *packer.Unpacker) bool {
if msgId == network7.MsgGameReadyToEnter {
msg := &messages7.Ready{ChunkHeader: &chunk.Header}
msg := &messages7.ReadyToEnter{ChunkHeader: &chunk.Header}
msg.Unpack(u)
packet.Messages = append(packet.Messages, msg)
} else if msgId == network7.MsgGameSvMotd {
@ -140,8 +144,9 @@ func (packet *Packet) unpackPayload(payload []byte) {
for _, c := range chunks {
if packet.unpackChunk(c) == false {
unknown := &messages7.Unknown{
Data: slices.Concat(c.Header.Pack(), c.Data),
Type: network7.TypeNet,
ChunkHeader: &c.Header,
Data: slices.Concat(c.Header.Pack(), c.Data),
Type: network7.TypeNet,
}
packet.Messages = append(packet.Messages, unknown)
}

View file

@ -135,12 +135,10 @@ func TestRepackUnknownMessages(t *testing.T) {
}
conn := Connection{}
result, err := conn.OnPacket(dump)
if err != nil {
t.Errorf("Unexpected error %v\n", err)
}
repack := result.Packet.Pack(&conn)
packet := Packet{}
packet.Unpack(dump)
repack := packet.Pack(&conn)
if !reflect.DeepEqual(repack, dump) {
t.Errorf("got %v, wanted %v", repack, dump)

View file

@ -86,39 +86,41 @@ func main() {
time.Sleep(10_000_000)
select {
case msg := <-ch:
result, err := client.OnPacket(msg)
packet := &protocol7.Packet{}
err := packet.Unpack(msg)
if err != nil {
panic(err)
}
if result != nil && result.Response != nil {
response := client.OnPacket(packet)
if response != nil {
// example of inspecting incoming trafic
for i, msg := range result.Packet.Messages {
if msg.MsgId() == network7.MsgGameSvChat {
var chat *messages7.SvChat
var ok bool
if chat, ok = result.Packet.Messages[i].(*messages7.SvChat); ok {
fmt.Printf("got chat msg: %s\n", chat.Message)
for i, _ := range packet.Messages {
var chat *messages7.SvChat
var ok bool
if chat, ok = packet.Messages[i].(*messages7.SvChat); ok {
fmt.Printf("got chat msg: %s\n", chat.Message)
// modify chat if this was a proxy
result.Packet.Messages[i] = chat
}
// modify chat if this was a proxy
packet.Messages[i] = chat
}
}
// example of modifying outgoing traffic
for i, msg := range result.Response.Messages {
for i, msg := range response.Messages {
if msg.MsgId() == network7.MsgCtrlConnect {
var connect *messages7.CtrlConnect
var ok bool
if connect, ok = result.Response.Messages[i].(*messages7.CtrlConnect); ok {
if connect, ok = response.Messages[i].(*messages7.CtrlConnect); ok {
connect.Token = [4]byte{0xaa, 0xaa, 0xaa, 0xaa}
result.Response.Messages[i] = connect
response.Messages[i] = connect
}
}
}
conn.Write(result.Response.Pack(client))
if len(response.Messages) > 0 || response.Header.Flags.Resend {
conn.Write(response.Pack(client))
}
}
default:
// do nothing