@mesh-tech/mesh-cli/dist/src/utils/socks-forward.js

CLI for Mesh platform development utilities

import * as net from "node:net";
export function ipv4ToBytes(ip) {
    const parts = ip.split(".");
    if (parts.length !== 4)
        throw new Error(`not an IPv4 address: ${ip}`);
    return parts.map((p) => {
        const n = Number(p);
        if (!Number.isInteger(n) || n < 0 || n > 255 || !/^\d+$/.test(p)) {
            throw new Error(`not an IPv4 address: ${ip}`);
        }
        return n;
    });
}
export function socks5ConnectRequest(ip, port) {
    return Buffer.from([0x05, 0x01, 0x00, 0x01, ...ipv4ToBytes(ip), (port >> 8) & 0xff, port & 0xff]);
}
const SOCKS_REPLY_MESSAGES = {
    0: "succeeded",
    1: "general SOCKS server failure",
    2: "connection not allowed by ruleset",
    3: "network unreachable",
    4: "host unreachable",
    5: "connection refused",
    6: "TTL expired",
    7: "command not supported",
    8: "address type not supported",
};
export function interpretSocksReply(code) {
    return { ok: code === 0, message: SOCKS_REPLY_MESSAGES[code] ?? `unknown SOCKS reply ${code}` };
}
export function createForwarder(opts) {
    const socksHost = opts.socksHost ?? "127.0.0.1";
    const server = net.createServer((client) => {
        const up = net.connect(opts.socksPort, socksHost);
        let buf = Buffer.alloc(0);
        let phase = 0;
        up.on("connect", () => up.write(Buffer.from([0x05, 0x01, 0x00])));
        up.on("data", (d) => {
            if (phase === 2)
                return;
            buf = Buffer.concat([buf, d]);
            if (phase === 0) {
                if (buf.length < 2)
                    return;
                buf = buf.subarray(2);
                phase = 1;
                up.write(socks5ConnectRequest(opts.targetIp, opts.targetPort));
            }
            if (phase === 1) {
                if (buf.length < 10)
                    return;
                const reply = interpretSocksReply(buf[1]);
                const leftover = buf.subarray(10);
                phase = 2;
                if (!reply.ok) {
                    up.destroy();
                    client.destroy();
                    return;
                }
                if (leftover.length)
                    client.write(leftover);
                client.pipe(up);
                up.pipe(client);
            }
        });
        client.on("error", () => up.destroy());
        up.on("error", () => client.destroy());
        client.on("close", () => up.destroy());
        up.on("close", () => client.destroy());
    });
    server.on("error", (err) => opts.onError?.(err));
    server.listen(opts.listenPort, "127.0.0.1");
    return server;
}