solidDoWant
134 lines
4.0 KiB
Go
134 lines
4.0 KiB
Go
package mcproto
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import (
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"bytes"
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"strings"
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"github.com/pkg/errors"
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)
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const invalidPacketDataBytesMsg = "data should be byte slice from Packet.Data"
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// DecodeHandshake takes the Packet.Data bytes and decodes a Handshake message from it
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func DecodeHandshake(data interface{}) (*Handshake, error) {
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dataBytes, ok := data.([]byte)
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if !ok {
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return nil, errors.New(invalidPacketDataBytesMsg)
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}
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handshake := &Handshake{}
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buffer := bytes.NewBuffer(dataBytes)
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var err error
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protocolVersion, err := ReadVarInt(buffer)
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if err != nil {
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return nil, err
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}
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handshake.ProtocolVersion = ProtocolVersion(protocolVersion)
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handshake.ServerAddress, err = ReadString(buffer)
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if err != nil {
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return nil, err
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}
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// Forge Mod Loader adds some data after the server address. Truncate it.
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handshake.ServerAddress, _, _ = strings.Cut(handshake.ServerAddress, string(rune(0)))
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handshake.ServerPort, err = ReadUnsignedShort(buffer)
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if err != nil {
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return nil, err
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}
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nextState, err := ReadVarInt(buffer)
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if err != nil {
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return nil, err
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}
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handshake.NextState = State(nextState)
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return handshake, nil
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}
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// DecodeLoginStart takes the Packet.Data bytes and decodes a LoginStart message from it
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func DecodeLoginStart(protocolVersion ProtocolVersion, data interface{}) (*LoginStart, error) {
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dataBytes, ok := data.([]byte)
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if !ok {
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return nil, errors.New(invalidPacketDataBytesMsg)
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}
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loginStart := NewLoginStart()
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buffer := bytes.NewBuffer(dataBytes)
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var err error
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loginStart.Name, err = ReadString(buffer)
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if err != nil {
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return loginStart, errors.Wrap(err, "failed to read username")
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}
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// These versions can send player keypair data. Ignore it.
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// References:
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// * https://github.com/MCCTeam/Minecraft-Console-Client/blob/f785f509f228bf787c237ac139e6f666a960819a/MinecraftClient/Protocol/Handlers/Protocol18.cs#L2808-L2828
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// * https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Protocol?oldid=2772902#Login_Start
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if protocolVersion >= ProtocolVersion1_19 && protocolVersion <= ProtocolVersion1_19_2 {
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hasSignatureData, err := ReadBoolean(buffer)
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if err != nil {
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return loginStart, errors.Wrap(err, "failed to read has signature data flag")
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}
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if hasSignatureData {
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// Read and discard the data
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_, err = ReadLong(buffer) // Expiration time
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if err != nil {
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return loginStart, errors.Wrap(err, "failed to read expiration time")
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}
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pubKeyLength, err := ReadVarInt(buffer) // Length of the public key
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if err != nil {
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return loginStart, errors.Wrap(err, "failed to read public key length")
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}
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_, err = ReadByteArray(buffer, pubKeyLength) // Public key data
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if err != nil {
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return loginStart, errors.Wrap(err, "failed to read public key")
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}
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signatureLength, err := ReadVarInt(buffer) // Length of the signature
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if err != nil {
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return loginStart, errors.Wrap(err, "failed to read signature length")
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}
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_, err = ReadByteArray(buffer, signatureLength) // Signature data
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if err != nil {
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return loginStart, errors.Wrap(err, "failed to read signature")
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}
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}
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}
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// References:
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// * https://github.com/MCCTeam/Minecraft-Console-Client/blob/f785f509f228bf787c237ac139e6f666a960819a/MinecraftClient/Protocol/Handlers/Protocol18.cs#L2831-L2853
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// * https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Protocol?oldid=2772944#Login_Start
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switch {
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case protocolVersion >= ProtocolVersion1_19_2 && protocolVersion < ProtocolVersion1_20_2:
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// Check to see if a UUID was provided at all
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hasUUID, err := ReadBoolean(buffer)
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if err != nil {
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return loginStart, errors.Wrap(err, "failed to read has uuid flag")
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}
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if !hasUUID {
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break
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}
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fallthrough
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case protocolVersion >= ProtocolVersion1_20_2:
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// For 1.20.2 and later, the UUID is always present
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playerUuid, err := ReadUuid(buffer)
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if err != nil {
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return loginStart, errors.Wrap(err, "failed to read player uuid")
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}
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loginStart.PlayerUuid = playerUuid
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default:
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// For versions before 1.19.2, the UUID is not present
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}
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return loginStart, nil
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}
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