"use strict"; const {isIP} = require("net"); const execa = require("execa"); const dests = new Set(["default", "0.0.0.0", "0.0.0.0/0", "::", "::/0"]); const args = { v4: ["-rn", "-f", "inet"], v6: ["-rn", "-f", "inet6"], }; const parse = stdout => { let result; (stdout || "").trim().split("\n").some(line => { const [target, gateway, _, iface] = line.split(/ +/) || []; if (dests.has(target) && gateway && isIP(gateway)) { result = {gateway, interface: (iface ? iface : null)}; return true; } }); if (!result) { throw new Error("Unable to determine default gateway"); } return result; }; const promise = async family => { const {stdout} = await execa("netstat", args[family]); return parse(stdout); }; const sync = family => { const {stdout} = execa.sync("netstat", args[family]); return parse(stdout); }; module.exports.v4 = () => promise("v4"); module.exports.v6 = () => promise("v6"); module.exports.v4.sync = () => sync("v4"); module.exports.v6.sync = () => sync("v6");