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1"use strict";
2
3const {isIP} = require("net");
4const execa = require("execa");
5const dests = new Set(["default", "0.0.0.0", "0.0.0.0/0", "::", "::/0"]);
6
7const args = {
8 v4: ["-rn", "-f", "inet"],
9 v6: ["-rn", "-f", "inet6"],
10};
11
12const parse = stdout => {
13 let result;
14
15 (stdout || "").trim().split("\n").some(line => {
16 const results = line.split(/ +/) || [];
17 const target = results[0];
18 const gateway = results[1];
19 const iface = results[5];
20 if (dests.has(target) && gateway && isIP(gateway)) {
21 result = {gateway, interface: (iface ? iface : null)};
22 return true;
23 }
24 });
25
26 if (!result) {
27 throw new Error("Unable to determine default gateway");
28 }
29
30 return result;
31};
32
33const promise = async family => {
34 const {stdout} = await execa("netstat", args[family]);
35 return parse(stdout);
36};
37
38const sync = family => {
39 const {stdout} = execa.sync("netstat", args[family]);
40 return parse(stdout);
41};
42
43module.exports.v4 = () => promise("v4");
44module.exports.v6 = () => promise("v6");
45
46module.exports.v4.sync = () => sync("v4");
47module.exports.v6.sync = () => sync("v6");