strom/tools/uncodeable_packet_hunter_proxy/main.go

package main

import (
	"crypto/sha256"
	"fmt"
	"log/slog"
	"os"

	"github.com/admin-else/strom/api"
	"github.com/admin-else/strom/client"
	"github.com/admin-else/strom/event"
	"github.com/admin-else/strom/proto"
	"github.com/admin-else/strom/proto_base"
	"github.com/admin-else/strom/proto_generated/v1_21_8"
	"github.com/admin-else/strom/server"
	"github.com/admin-else/strom/text"
)

type ProxyClient struct {
	*proto.Conn
	Server *Proxy
}

func (p *ProxyClient) OnDefault(event event.Unhandled) (err error) {
	packet, isPacket := event.Val.(proto_base.EncodeDecodeAble)
	if !isPacket {
		return
	}
	err = p.Server.Send(packet)
	return
}

func (p *ProxyClient) OnCycle(_ event.Tick) (err error) {
	return
}

func (p *ProxyClient) OnStart(_ event.Start) (err error) {
	return
}

func (p *ProxyClient) OnUnCodeAble(packet *proto.UnCodablePacket) (err error) {
	err = p.OnDefault(event.Unhandled{Val: packet})
	if err != nil {
		return
	}
	SaveUnCodeAbleAsTest(proto_base.ToServer, packet)
	return
}

type Proxy struct {
	*proto.Conn
	Client *ProxyClient
}

func (p *Proxy) OnDefault(event event.Unhandled) (err error) {
	packet, isPacket := event.Val.(proto_base.EncodeDecodeAble)
	if !isPacket {
		return
	}
	err = p.Client.Send(packet)
	return
}

func (p *Proxy) OnCycle(_ event.Tick) (err error) {
	return
}

func (p *Proxy) OnStart(_ event.Start) (err error) {
	return
}

func (p *Proxy) OnFinishConfiguration(packet *v1_21_8.ConfigurationToServerPacketFinishConfiguration) (err error) {
	err = p.OnDefault(event.Unhandled{Val: packet})
	if err != nil {
		return
	}
	p.SetState(proto_base.Play)
	p.Client.SetState(proto_base.Play)
	return
}

func (p *Proxy) OnUnCodeAble(packet *proto.UnCodablePacket) (err error) {
	err = p.OnDefault(event.Unhandled{Val: packet})
	if err != nil {
		return
	}
	SaveUnCodeAbleAsTest(proto_base.ToClient, packet)
	return
}

const TestSrcF = `package failed_packets_test

import (
	"bytes"
	"testing"

	"github.com/admin-else/strom/proto_generated/v1_21_8"
)

// Error: %v
func TestFailedPacket%10X(t *testing.T) {
	p := v1_21_8.Play%vPacket{}
	b := bytes.NewBuffer(%#v)
	err := p.Decode(b)
	if err != nil {
		t.Fatal(err)
	}
}
`

func SaveUnCodeAbleAsTest(d proto_base.Direction, packet *proto.UnCodablePacket) {
	hUntrimmed := sha256.Sum256(packet.Data)
	h := hUntrimmed[:8]
	f, err := os.Create(fmt.Sprintf(".failed_packets/%v_%10x_test.go", len(packet.Data), h))
	if err != nil {
		panic(err)
	}
	//goland:noinspection GoUnhandledErrorResult
	defer f.Close()
	_, err = fmt.Fprintf(f, TestSrcF, packet.Err, h, d.Opposite(), packet.Data)
	if err != nil {
		panic(err)
	}
	slog.Info("Packet failed to parse", "error", packet.Err, "saved", f.Name(), "data", fmt.Sprintf("%q", packet.Data))
}

var StatusResponse = server.StatusResponse{
	Version: server.StatusResponseVersion{
		Name:     text.Pretty("STROM"),
		Protocol: 772,
	},
	Players:            server.StatusResponsePlayers{},
	Description:        text.Pretty("Hunt the uncodeable packets"),
	Favicon:            "",
	EnforcesSecureChat: false,
}

func main() {
	slog.SetLogLoggerLevel(slog.LevelDebug)
	err := server.StartServerWithOnConn(":25565", func(serveeConn *proto.Conn) (err error) {
		p := &Proxy{Conn: serveeConn, Client: nil}
		acc := api.NewOfflineAccount("sigma")
		_, err = server.ServeLogin(serveeConn, server.WithOtherAccount(acc), server.WithStatus(StatusResponse))
		if err != nil {
			return
		}
		c, err := client.ConnectAndLogin("127.0.0.1:25566", acc)
		if err != nil {
			return
		}
		pc := &ProxyClient{Conn: c, Server: p}
		p.Client = pc
		errChan := make(chan error)
		defer pc.Close()
		go func() {
			errChan <- pc.Start(pc)
		}()
		go func() {
			errChan <- p.Start(p)
		}()
		err = <-errChan
		return
	})
	if err != nil {
		panic(err)
	}
}