Change project dir structure

server/entranceserver/crypto.go

@@ -0,0 +1,57 @@
+package entranceserver
+
+import (
+	"encoding/binary"
+)
+
+var (
+	_bin8Key     = []byte{0x01, 0x23, 0x34, 0x45, 0x56, 0xAB, 0xCD, 0xEF}
+	_sum32Table0 = []byte{0x7A, 0xAA, 0x97, 0x53, 0x66, 0x12, 0xDE, 0xDE, 0x35}
+	_sum32Table1 = []byte{0x35, 0x7A, 0xAA, 0x97, 0x53, 0x66, 0x12}
+)
+
+// CalcSum32 calculates the custom MHF "sum32" checksum of the given data.
+func CalcSum32(data []byte) uint32 {
+	tableIdx0 := byte(len(data) & 0xFF)
+	tableIdx1 := byte(data[len(data)>>1])
+
+	out := make([]byte, 4)
+	for i := 0; i < len(data); i++ {
+		tableIdx0++
+		tableIdx1++
+
+		tmp := byte((_sum32Table0[tableIdx1%9] ^ _sum32Table1[tableIdx0%7]) ^ data[i])
+		out[i&3] = (out[i&3] + tmp) & 0xFF
+
+	}
+
+	return binary.BigEndian.Uint32(out)
+}
+
+// EncryptBin8 encrypts the given data using MHF's "binary8" encryption.
+func EncryptBin8(data []byte, key byte) []byte {
+	curKey := uint32(((54323 * uint(key)) + 1) & 0xFFFFFFFF)
+
+	var output []byte
+	for i := 0; i < len(data); i++ {
+		tmp := (_bin8Key[i&7] ^ byte((curKey>>13)&0xFF))
+		output = append(output, data[i]^tmp)
+		curKey = uint32(((54323 * uint(curKey)) + 1) & 0xFFFFFFFF)
+	}
+
+	return output
+}
+
+// DecryptBin8 decrypts the given MHF "binary8" data.
+func DecryptBin8(data []byte, key byte) []byte {
+	curKey := uint32(((54323 * uint(key)) + 1) & 0xFFFFFFFF)
+
+	var output []byte
+	for i := 0; i < len(data); i++ {
+		tmp := (data[i] ^ byte((curKey>>13)&0xFF))
+		output = append(output, tmp^_bin8Key[i&7])
+		curKey = uint32(((54323 * uint(curKey)) + 1) & 0xFFFFFFFF)
+	}
+
+	return output
+}

server/entranceserver/crypto_test.go

@@ -0,0 +1,73 @@
+package entranceserver
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+	"testing"
+)
+
+var tests = []struct {
+	data          []byte
+	sum           uint32
+	encryptedData []byte
+	encryptionKey byte
+}{
+	{
+		[]byte{0x4C, 0x6F, 0x72, 0x65, 0x6D, 0x20},
+		0xAE6CA2C,
+		[]byte{0x7E, 0x4C, 0x1D, 0x16, 0x9D, 0x46},
+		0x55,
+	},
+	{
+		[]byte{0x69, 0x70, 0x73, 0x75, 0x6D, 0x20, 0x64, 0x6F, 0x6C, 0x6F, 0x72, 0x20, 0x73, 0x69, 0x74, 0x20, 0x61, 0x6D, 0x65, 0x74, 0x2C, 0x20},
+		0xCE5F1E96,
+		[]byte{0x41, 0x65, 0xFF, 0x74, 0x64, 0x45, 0xB8, 0xB1, 0x18, 0xB0, 0x94, 0xA3, 0xF8, 0xD, 0xBF, 0x3C, 0xC8, 0x24, 0xE2, 0xEC, 0x3B, 0xCE},
+		0x7A,
+	},
+	{
+		[]byte{0x63, 0x6F, 0x6E, 0x73, 0x65, 0x63, 0x74, 0x65, 0x74, 0x75, 0x72, 0x20, 0x61, 0x64, 0x69, 0x70, 0x69, 0x73, 0x63, 0x69, 0x6E, 0x67, 0x20, 0x65, 0x6C, 0x69, 0x74, 0x2C, 0x20},
+		0xF3EECEBB,
+		[]byte{0xE, 0xBB, 0x19, 0xA5, 0xB9, 0x34, 0xFE, 0x51, 0x0, 0x61, 0x2D, 0x38, 0xB2, 0x98, 0xC2, 0xE0, 0x17, 0xDE, 0x6E, 0xE3, 0x6C, 0x1E, 0x19, 0xB6, 0x8C, 0x57, 0x32, 0x32, 0xD8},
+		0xF8,
+	},
+}
+
+func TestSum32(t *testing.T) {
+	for k, test := range tests {
+		testname := fmt.Sprintf("sum32_test_%d", k)
+		t.Run(testname, func(t *testing.T) {
+			gotSum := CalcSum32(test.data)
+
+			if gotSum != test.sum {
+				t.Errorf("got sum32 0x%X, want 0x%X", gotSum, test.sum)
+			}
+		})
+	}
+}
+
+func TestEncryptBin8(t *testing.T) {
+	for k, test := range tests {
+		testname := fmt.Sprintf("encrypt_bin8_test_%d", k)
+		t.Run(testname, func(t *testing.T) {
+			gotEncData := EncryptBin8(test.data, test.encryptionKey)
+
+			if !bytes.Equal(gotEncData, test.encryptedData) {
+				t.Errorf("got\n\t%s\nwant\n\t%s", hex.Dump(gotEncData), hex.Dump(test.encryptedData))
+			}
+		})
+	}
+}
+
+func TestDecryptBin8(t *testing.T) {
+	for k, test := range tests {
+		testname := fmt.Sprintf("decrypt_bin8_test_%d", k)
+		t.Run(testname, func(t *testing.T) {
+			gotDecData := DecryptBin8(test.encryptedData, test.encryptionKey)
+
+			if !bytes.Equal(gotDecData, test.data) {
+				t.Errorf("got\n\t%s\nwant\n\t%s", hex.Dump(gotDecData), hex.Dump(test.data))
+			}
+		})
+	}
+}

server/entranceserver/entrance_server.go

@@ -0,0 +1,120 @@
+package entranceserver
+
+import (
+	"database/sql"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"net"
+	"sync"
+
+	"github.com/Andoryuuta/Erupe/config"
+	"github.com/Andoryuuta/Erupe/network"
+	"go.uber.org/zap"
+)
+
+// Server is a MHF entrance server.
+type Server struct {
+	sync.Mutex
+	logger         *zap.Logger
+	erupeConfig    *config.Config
+	db             *sql.DB
+	listener       net.Listener
+	isShuttingDown bool
+}
+
+// Config struct allows configuring the server.
+type Config struct {
+	Logger      *zap.Logger
+	DB          *sql.DB
+	ErupeConfig *config.Config
+}
+
+// NewServer creates a new Server type.
+func NewServer(config *Config) *Server {
+	s := &Server{
+		logger:      config.Logger,
+		erupeConfig: config.ErupeConfig,
+		db:          config.DB,
+	}
+	return s
+}
+
+// Start starts the server in a new goroutine.
+func (s *Server) Start() error {
+
+	l, err := net.Listen("tcp", fmt.Sprintf(":%d", s.erupeConfig.Entrance.Port))
+	if err != nil {
+		return err
+	}
+
+	s.listener = l
+
+	go s.acceptClients()
+
+	return nil
+}
+
+// Shutdown exits the server gracefully.
+func (s *Server) Shutdown() {
+	s.logger.Debug("Shutting down")
+
+	s.Lock()
+	s.isShuttingDown = true
+	s.Unlock()
+
+	// This will cause the acceptor goroutine to error and exit gracefully.
+	s.listener.Close()
+}
+
+//acceptClients handles accepting new clients in a loop.
+func (s *Server) acceptClients() {
+	for {
+		conn, err := s.listener.Accept()
+		if err != nil {
+			// Check if we are shutting down and exit gracefully if so.
+			s.Lock()
+			shutdown := s.isShuttingDown
+			s.Unlock()
+
+			if shutdown {
+				break
+			} else {
+				continue
+			}
+		}
+
+		// Start a new goroutine for the connection so that we don't block other incoming connections.
+		go s.handleEntranceServerConnection(conn)
+	}
+}
+
+func (s *Server) handleEntranceServerConnection(conn net.Conn) {
+	// Client initalizes the connection with a one-time buffer of 8 NULL bytes.
+	nullInit := make([]byte, 8)
+	n, err := io.ReadFull(conn, nullInit)
+	if err != nil {
+		s.logger.Warn("Failed to read 8 NULL init", zap.Error(err))
+		return
+	} else if n != len(nullInit) {
+		s.logger.Warn("io.ReadFull couldn't read the full 8 byte init.")
+		return
+	}
+
+	// Create a new encrypted connection handler and read a packet from it.
+	cc := network.NewCryptConn(conn)
+	pkt, err := cc.ReadPacket()
+	if err != nil {
+		s.logger.Warn("Error reading packet", zap.Error(err))
+		return
+	}
+
+	s.logger.Debug("Got entrance server command:\n", zap.String("raw", hex.Dump(pkt)))
+
+	data := makeResp(s.erupeConfig.Entrance.Entries)
+	cc.SendPacket(data)
+
+	// Close because we only need to send the response once.
+	// Any further requests from the client will come from a new connection.
+	conn.Close()
+}

server/entranceserver/make_resp.go

@@ -0,0 +1,86 @@
+package entranceserver
+
+import (
+	"encoding/binary"
+	"net"
+
+	"github.com/Andoryuuta/Erupe/config"
+	"github.com/Andoryuuta/byteframe"
+)
+
+func paddedString(x string, size uint) []byte {
+	out := make([]byte, size)
+	copy(out, x)
+
+	// Null terminate it.
+	out[len(out)-1] = 0
+	return out
+}
+
+func encodeServerInfo(serverInfos []config.EntranceServerInfo) []byte {
+	bf := byteframe.NewByteFrame()
+
+	for serverIdx, si := range serverInfos {
+		bf.WriteUint32(binary.LittleEndian.Uint32(net.ParseIP(si.IP).To4()))
+		bf.WriteUint16(16 + uint16(serverIdx))
+		bf.WriteUint16(si.Unk2)
+		bf.WriteUint16(uint16(len(si.Channels)))
+		bf.WriteUint8(si.Type)
+		bf.WriteUint8(si.Season)
+		bf.WriteUint8(si.Unk6)
+		bf.WriteBytes(paddedString(si.Name, 66))
+		bf.WriteUint32(si.AllowedClientFlags)
+
+		for channelIdx, ci := range si.Channels {
+			bf.WriteUint16(ci.Port)
+			bf.WriteUint16(16 + uint16(channelIdx))
+			bf.WriteUint16(ci.MaxPlayers)
+			bf.WriteUint16(ci.CurrentPlayers)
+			bf.WriteUint16(ci.Unk4)
+			bf.WriteUint16(ci.Unk5)
+			bf.WriteUint16(ci.Unk6)
+			bf.WriteUint16(ci.Unk7)
+			bf.WriteUint16(ci.Unk8)
+			bf.WriteUint16(ci.Unk9)
+			bf.WriteUint16(ci.Unk10)
+			bf.WriteUint16(ci.Unk11)
+			bf.WriteUint16(ci.Unk12)
+			bf.WriteUint16(ci.Unk13)
+		}
+	}
+
+	return bf.Data()
+}
+
+func makeHeader(data []byte, respType string, entryCount uint16, key byte) []byte {
+	bf := byteframe.NewByteFrame()
+	bf.WriteBytes([]byte(respType))
+	bf.WriteUint16(entryCount)
+	bf.WriteUint16(uint16(len(data)))
+	if len(data) > 0 {
+		bf.WriteUint32(CalcSum32(data))
+		bf.WriteBytes(data)
+	}
+
+	dataToEncrypt := bf.Data()
+
+	bf = byteframe.NewByteFrame()
+	bf.WriteUint8(key)
+	bf.WriteBytes(EncryptBin8(dataToEncrypt, key))
+	return bf.Data()
+}
+
+func makeResp(servers []config.EntranceServerInfo) []byte {
+	rawServerData := encodeServerInfo(servers)
+
+	bf := byteframe.NewByteFrame()
+	bf.WriteBytes(makeHeader(rawServerData, "SV2", uint16(len(servers)), 0x00))
+
+	// TODO(Andoryuuta): Figure out what this user data is.
+	// Is it for the friends list at the world selection screen?
+	// If so, how does it work without the entrance server connection being authenticated?
+	bf.WriteBytes(makeHeader([]byte{}, "USR", 0, 0x00))
+
+	return bf.Data()
+
+}