sysinfo: add interface to get IPv6 address

src/sysinfo/network-interface.js

@@ -1,7 +1,8 @@
 'use strict';
 
 exports = module.exports = {
-    getServerIp,
+    getServerIPv4,
+    getServerIPv6,
     testConfig
 };
 
@@ -11,7 +12,7 @@ const assert = require('assert'),
     os = require('os'),
     safe = require('safetydance');
 
-async function getServerIp(config) {
+async function getServerIPv4(config) {
     assert.strictEqual(typeof config, 'object');
 
     const ifaces = os.networkInterfaces();
@@ -25,12 +26,26 @@ async function getServerIp(config) {
     return addresses[0];
 }
 
+async function getServerIPv6(config) {
+    assert.strictEqual(typeof config, 'object');
+
+    const ifaces = os.networkInterfaces();
+    const iface = ifaces[config.ifname]; // array of addresses
+    if (!iface) throw new BoxError(BoxError.NETWORK_ERROR, `No interface named ${config.ifname}`);
+
+    const addresses = iface.filter(i => i.family === 'IPv6').map(i => i.address);
+    if (addresses.length === 0) throw new BoxError(BoxError.NETWORK_ERROR, `${config.ifname} does not have any IPv4 address`);
+    if (addresses.length > 1) debug(`${config.ifname} has multiple ipv6 - ${JSON.stringify(addresses)}. choosing the first one.`);
+
+    return addresses[0];
+}
+
 async function testConfig(config) {
     assert.strictEqual(typeof config, 'object');
     assert.strictEqual(typeof callback, 'function');
 
     if (typeof config.ifname !== 'string') return new BoxError(BoxError.BAD_FIELD, 'ifname is not a string');
 
-    const [error] = await safe(getServerIp(config));
+    const [error] = await safe(getServerIPv4(config));
     return error || null;
 }