Mostly working handshake handler & MOTD handler

utils.ts

@@ -1,25 +1,31 @@
-import { v3 } from "uuid"
 import WebSocket from "ws"
-import { ProxiedPlayer } from "./classes.js"
 import {
     encodeULEB128 as encodeVarInt,
     decodeULEB128 as decodeVarInt,
     encodeSLEB128 as encodeSVarInt,
     decodeSLEB128 as decodeSVarInt
 } from "@thi.ng/leb128"
-import { DisconnectReason, EaglerPacketId, MAGIC_ENDING_IDENTIFYS_BYTES } from "./eaglerPacketDef.js"
+import { DisconnectReason, EAGLERCRAFT_SKIN_CHANNEL_NAME, EaglerPacketId, MAGIC_BUILTIN_SKIN_BYTES, MAGIC_ENDING_IDENTIFY_S_BYTES } from "./eaglerPacketDef.js"
 import { Logger } from "./logger.js"
-import { State } from "./types.js"
-import { toBuffer } from "uuid-buffer"
+import { ChannelMessageType, Chat, ChatColor, ProxiedPlayer, State, UUID } from "./types.js"
+import { toBuffer, toString as uuidToString } from "uuid-buffer"
 import * as mc from "minecraft-protocol"
 import { config } from "./config.js"
+import sharp from "sharp"
+import { createHash, randomUUID } from "crypto"
+import { encodeSSkinDl, encodeSSkinDlBuiltin, packChannelMessage, processClientReqPacket } from "./eaglerSkin.js"
 
-const MAGIC_UUID = "a7e774bc-7ea4-11ed-9a58-1f9e14304a59"
 const logger = new Logger("LoginHandler")
 const USERNAME_REGEX = /[^0-9^a-z^A-Z^_]/gi
 
 export function genUUID(user: string): string {
-    return v3(user, MAGIC_UUID)
+    const str = `OfflinePlayer:${user}`
+    let md5Bytes = createHash('md5').update(str).digest()
+    md5Bytes[6]  &= 0x0f;  /* clear version        */
+    md5Bytes[6]  |= 0x30;  /* set to version 3     */
+    md5Bytes[8]  &= 0x3f;  /* clear variant        */
+    md5Bytes[8]  |= 0x80;  /* set to IETF variant  */
+    return uuidToString(md5Bytes)
 }
 
 export function bufferizeUUID(uuid: string): Buffer {
@@ -33,17 +39,30 @@ export function validateUsername(user: string): void | never {
         throw new Error("Invalid username. Username can only contain alphanumeric characters, and the underscore (_) character.")
 }
 
-export function disconnect(player: ProxiedPlayer, message: string, code?: DisconnectReason) {
+export function chatToPlainString(chat: Chat): string {
+    let ret = ''
+    if (chat.text != null) ret += chat.text
+    if (chat.extra != null) {
+        chat.extra.forEach(extra => {
+            ret += extra.text
+        })
+    }
+    return ret
+}
+
+export function disconnect(player: ProxiedPlayer, message: Chat | string, code?: DisconnectReason) {
     if (player.state == State.POST_HANDSHAKE) {
-        const messageLen = encodeVarInt(message.length)
-        const d = Buffer.alloc(1 + messageLen.length + message.length)
-        d.set([0x40, ...messageLen, ...Buffer.from(message)])
+        const message_m = (typeof message == 'string' ? JSON.stringify({ text: message }) : JSON.stringify(message)) + 0x0
+        const messageLen = encodeVarInt(message_m.length)
+        const d = Buffer.alloc([0x40, ...messageLen, ...Buffer.from(message_m)].length)
+        d.set([0x40, ...messageLen, ...Buffer.from(message_m)])
         player.ws.send(d)
         player.ws.close()
     } else {
-        const messageLen = encodeVarInt(message.length), codeEnc = encodeVarInt(code ?? DisconnectReason.CUSTOM)
-        const d = Buffer.alloc(1 + codeEnc.length + messageLen.length + message.length)
-        d.set([0xff,...codeEnc, ...messageLen, ...Buffer.from(message)])
+        const message_m = (typeof message == 'string' ? message : chatToPlainString(message))
+        const messageLen = encodeVarInt(message_m.length), codeEnc = encodeVarInt(code ?? DisconnectReason.CUSTOM)
+        const d = Buffer.alloc([0xff,...codeEnc, ...messageLen, ...Buffer.from(message_m)].length)
+        d.set([0xff,...codeEnc, ...messageLen, ...Buffer.from(message_m)])
         player.ws.send(d)
         player.ws.close()
     }
@@ -88,7 +107,7 @@ export function awaitPacket(ws: WebSocket, id?: EaglerPacketId): Promise<Buffer>
 
 export function loginServer(ip: string, port: number, client: ProxiedPlayer) {
     return new Promise<void>((res, rej) => {
-        let receivedCompression = false
+        let blockedSuccessLogin = false
         const mcClient = mc.createClient({
             host: ip,
             port: port,
@@ -100,28 +119,20 @@ export function loginServer(ip: string, port: number, client: ProxiedPlayer) {
             mcClient.end()
             rej(err)
         })
-        mcClient.on('end', () => {
-            client.ws.close()
-        })
         mcClient.on('connect', () => {
             client.remoteConnection = mcClient
+            mcClient.on('end', () => {
+                client.ws.close()
+            })
             logger.info(`Player ${client.username} has been connected to the server.`)
             res()
         })
         mcClient.on('raw', p => {
-            if (p[0] == 0x03 && !receivedCompression) {
-                receivedCompression = true
-                const compT = {
-                    id: null,
-                    thres: null
-                }
-                const id = decodeVarInt(p)
-                compT.id = Number(id[0])
-                const thres = decodeSVarInt(p.subarray(id[1]))
-                compT.thres = thres[0]
-
-                client.compressionThreshold = compT.thres
+            // block the login success packet to fix the bug that prints the UUID in chat on join
+            if (p[0] == 0x02 && blockedSuccessLogin) {
                 client.ws.send(p)
+            } else if (p[0] == 0x02) {
+                blockedSuccessLogin = !blockedSuccessLogin
             } else {
                 client.ws.send(p)
             }
@@ -136,11 +147,10 @@ export async function doHandshake(client: ProxiedPlayer, initialPacket: Buffer)
             client.remoteConnection.end()
         }
         PROXY.players.delete(client.username)
-        PROXY.playerStats.onlineCount -= 1
         logger.info(`Client [/${client.ip}:${client.remotePort}]${client.username ? ` (${client.username})` : ""} disconnected from the server.`)
     })
-    if (PROXY.players.size + 1 > PROXY.playerStats.max) {
-        disconnect(client, "The proxy is full!", DisconnectReason.CUSTOM)
+    if (PROXY.players.size + 1 > PROXY.config.maxPlayers) {
+        disconnect(client, ChatColor.YELLOW + "The proxy is full!", DisconnectReason.CUSTOM)
         return
     }
     const identifyC = {
@@ -164,8 +174,8 @@ export async function doHandshake(client: ProxiedPlayer, initialPacket: Buffer)
     if (true) {
         const brandingLen = encodeVarInt(PROXY.brand.length), brand = PROXY.brand
         const verLen = encodeVarInt(PROXY.version.length), version = PROXY.version
-        const buff = Buffer.alloc(2 + MAGIC_ENDING_IDENTIFYS_BYTES.length + brandingLen.length + brand.length + verLen.length + version.length)
-        buff.set([EaglerPacketId.IDENTIFY_SERVER, 0x01, ...brandingLen, ...Buffer.from(brand), ...verLen, ...Buffer.from(version), ...Buffer.from(MAGIC_ENDING_IDENTIFYS_BYTES)])
+        const buff = Buffer.alloc(2 + MAGIC_ENDING_IDENTIFY_S_BYTES.length + brandingLen.length + brand.length + verLen.length + version.length)
+        buff.set([EaglerPacketId.IDENTIFY_SERVER, 0x01, ...brandingLen, ...Buffer.from(brand), ...verLen, ...Buffer.from(version), ...Buffer.from(MAGIC_ENDING_IDENTIFY_S_BYTES)])
         client.ws.send(buff)
     }
     client.clientBrand = identifyC.branding
@@ -181,61 +191,189 @@ export async function doHandshake(client: ProxiedPlayer, initialPacket: Buffer)
     if (login[0] === EaglerPacketId.LOGIN) {
         const Iid = decodeVarInt(login)
         loginP.id = Number(Iid[0])
-        const usernameLen = decodeVarInt(login.subarray(loginP[1]))
+        const usernameLen = decodeVarInt(login.subarray(Iid[1]))
         loginP.usernameLen = Number(usernameLen[0])
         loginP.username = login.subarray(Iid[1] + usernameLen[1], Iid[1] + usernameLen[1] + loginP.usernameLen).toString()
         const randomStrLen = decodeVarInt(login.subarray(Iid[1] + usernameLen[1] + loginP.usernameLen))
         loginP.randomStrLen = Number(randomStrLen[0])
         loginP.randomStr = login.subarray(Iid[1] + usernameLen[1] + loginP.usernameLen + randomStrLen[1], Iid[1] + usernameLen[1] + loginP.usernameLen + randomStrLen[1] + loginP.randomStrLen).toString()
+        
         client.username = loginP.username
         client.uuid = genUUID(client.username)
         try { validateUsername(client.username) }
         catch (err) {
-            disconnect(client, err.message, DisconnectReason.BAD_USERNAME)
+            disconnect(client, ChatColor.RED + err.message, DisconnectReason.CUSTOM)
             return
         }
         if (PROXY.players.has(client.username)) {
-            disconnect(client, `Duplicate username: ${client.username}. Please connect under a different username.`, DisconnectReason.DUPLICATE_USERNAME)
+            disconnect(client, `Duplicate username: ${client.username}. Please connect under a different username.`, DisconnectReason.CUSTOM)
             return
         }
         PROXY.players.set(client.username, client)
         if (true) {
             const usernameLen = encodeVarInt(client.username.length), username = client.username
-            const uuidLen = encodeVarInt(client.uuid.length), uuid = client.uuid
-            const buff = Buffer.alloc(1 + usernameLen.length + username.length + uuidLen.length + uuid.length)
-            buff.set([EaglerPacketId.LOGIN_ACK, ...usernameLen, ...Buffer.from(username), ...uuidLen, ...Buffer.from(uuid)])
+            const uuid = bufferizeUUID(client.uuid)
+            const buff = Buffer.alloc(1 + usernameLen.length + username.length + uuid.length)
+            buff.set([EaglerPacketId.LOGIN_ACK, ...usernameLen, ...Buffer.from(username), ...Buffer.from(uuid)])
             client.ws.send(buff)
-            
             if (true) {
                 const [skin, ready] = await Promise.all([awaitPacket(client.ws, EaglerPacketId.SKIN), awaitPacket(client.ws, EaglerPacketId.C_READY)])
                 if (ready[0] != 0x08) {
                     logger.error(`Client [/${client.ip}:${client.remotePort}] sent an unexpected packet! Disconnecting.`)
-                    disconnect(client, "Received bad packet", DisconnectReason.UNEXPECTED_PACKET)
+                    disconnect(client, ChatColor.RED + "Received bad packet.", DisconnectReason.CUSTOM)
                     client.ws.close()
                     return
                 }
+                if (true) {
+                    const skinP = {
+                        id: null,
+                        skinVerLen: null,
+                        skinVer: null, // skin_v1
+                        type: null, // CUSTOM or BUILTIN
+                        skinId: null,
+                        skinDimens: null,
+                        skin: null
+                    }
+                    const Iid = decodeVarInt(skin)
+                    skinP.id = Number(Iid[0])
+                    const skinVerLen = decodeVarInt(skin.subarray(Iid[1]))
+                    skinP.skinVerLen = Number(skinVerLen[0])
+                    skinP.skinVer = skin.subarray(Iid[1] + skinVerLen[1], Iid[1] + skinVerLen[1] + skinP.skinVerLen).toString()
+                    const typebuff = skin.subarray(Iid[1] + skinVerLen[1] + skinP.skinVerLen, Iid[1] + skinVerLen[1] + skinP.skinVerLen + MAGIC_BUILTIN_SKIN_BYTES.length)
+                    if (typebuff.compare(Buffer.from(MAGIC_BUILTIN_SKIN_BYTES)) == 0) {
+                        skinP.type = "BUILTIN"
+                        skinP.skinId = Number(decodeVarInt(skin.subarray(Iid[1] + skinVerLen[1] + skinP.skinVerLen + MAGIC_BUILTIN_SKIN_BYTES.length))[0])
+                    } else {
+                        skinP.type = "CUSTOM"
+                        const skinSqrt = decodeVarInt(skin.subarray(Iid[1] + skinVerLen[1] + skinP.skinVerLen)), dimensions = Number(skinSqrt[0]) * Number(skinSqrt[0]) * 3
+                        skinP.skinDimens = dimensions
+                        skinP.skin = skin.subarray(Iid[1] + skinVerLen[1] + skinP.skinVerLen + skinSqrt[1] + 16)
+                        console.log(skinP.skin.length)
+                        if (skinP.skin.length > 16385) {
+                            disconnect(client, ChatColor.RED + "Invalid skin received!")
+                            return
+                        }
+                        console.log(skinP.skin[skinP.skin.length - 1])
+                    }
+                    client.skin = {
+                        type: skinP.type,
+                        skinId: skinP.skinId,
+                        customSkin: skinP.skin
+                    }
+                }
 
                 const buff = Buffer.alloc(1)
                 buff.set([EaglerPacketId.COMPLETE_HANDSHAKE])
                 client.ws.send(buff)
 
                 client.state = State.POST_HANDSHAKE
-                PROXY.playerStats.onlineCount += 1
 
-                logger.info(`Client [/${client.ip}:${client.remotePort}] authenticated as player "${client.username}" and passed handshake. Connecting!`)
+                logger.info(`Client [/${client.ip}:${client.remotePort}] authenticated as player ${client.username} (${client.uuid}) and passed handshake. Connecting!`)
                 try { await loginServer(config.server.host, config.server.port, client) }
                 catch (err) {
                     logger.error(`Could not connect to remote server at [/${config.server.host}:${config.server.port}]: ${err}`)
-                    disconnect(client, "Failed to connect to server. Please try again later.", DisconnectReason.CUSTOM)
+                    disconnect(client, ChatColor.RED + "Failed to connect to server. Please try again later.", DisconnectReason.CUSTOM)
                     client.state = State.DISCONNECTED
                     client.ws.close()
                     return
                 }
+
+                if (client.queuedEaglerSkinPackets.length > 0) {
+                    for (const packet of client.queuedEaglerSkinPackets) {
+                        processClientReqPacket(packet, client)
+                    }
+                }
             }
         }
     } else {
         logger.error(`Client [/${client.ip}:${client.remotePort}] sent an unexpected packet! Disconnecting.`)
-        disconnect(client, "Received bad packet", DisconnectReason.UNEXPECTED_PACKET)
+        disconnect(client, ChatColor.RED + "Received bad packet", DisconnectReason.CUSTOM)
         client.ws.close()
     }
+}
+
+export type MotdPlayer = {
+    name: string,
+    id: UUID
+}
+
+export type MotdJSONRes = {
+    brand: string,
+    cracked: true,
+    data: {
+        cache: true,
+        icon: boolean,
+        max: number,
+        motd: [string, string],
+        online: number,
+        players: string[],
+    },
+    name: string,
+    secure: false,
+    time: ReturnType<typeof Date.now>,
+    type: "motd",
+    uuid: ReturnType<typeof randomUUID>,
+    vers: string
+}
+
+// a 16384 byte array
+export type MotdServerLogo = Buffer
+
+const ICON_SQRT = 64
+
+export function generateMOTDImage(file: Buffer): Promise<MotdServerLogo> {
+    return new Promise<MotdServerLogo>((res, rej) => {
+        sharp(file)
+            .resize(ICON_SQRT, ICON_SQRT, {
+                kernel: 'nearest'
+            })
+            .raw({
+                depth: 'uchar'
+            })
+            .toBuffer()
+            .then(buff => {
+                for (const pixel of buff) {
+                    if ((pixel & 0xFFFFFF) == 0) {
+                        buff[buff.indexOf(pixel)] = 0
+                    }
+                }
+                res(buff)
+            })
+            .catch(rej)
+    })
+}
+
+export function handleMotd(player: Partial<ProxiedPlayer>) {
+    const names = []
+    for (const [username, player] of PROXY.players) {
+        if (names.length > 0) {
+            names.push(`${ChatColor.GRAY}${ChatColor.ITALIC}(and ${PROXY.players.size - names.length} more)`)
+            break
+        } else {
+            names.push(username)
+        }
+    }
+
+    player.ws.send(JSON.stringify({
+        brand: PROXY.brand,
+        cracked: true,
+        data: {
+            cache: true,
+            icon: PROXY.MOTD.icon ? true : false,
+            max: PROXY.config.maxPlayers,
+            motd: PROXY.MOTD.motd,
+            online: PROXY.players.size,
+            players: names
+        },
+        name: PROXY.serverName,
+        secure: false,
+        time: Date.now(),
+        type: "motd",
+        uuid: PROXY.proxyUUID,
+        vers: PROXY.MOTDVersion
+    } as MotdJSONRes))
+    if (PROXY.MOTD.icon) {
+        player.ws.send(PROXY.MOTD.icon)
+    }
+    player.ws.close()
 }