fold sysinfo into network

the backends are network backends

src/network/network-interface.js

@@ -0,0 +1,60 @@
+'use strict';
+
+exports = module.exports = {
+    getIPv4,
+    getIPv6,
+    testIPv4Config,
+    testIPv6Config
+};
+
+const assert = require('assert'),
+    BoxError = require('../boxerror.js'),
+    debug = require('debug')('box:network/network-interface'),
+    os = require('os'),
+    safe = require('safetydance');
+
+async function getIPv4(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 ${config.ifname}`);
+
+    const addresses = iface.filter(i => i.family === 'IPv4').map(i => i.address);
+    if (addresses.length === 0) throw new BoxError(BoxError.NETWORK_ERROR, `${config.ifname} does not have any IPv4 address`);
+    if (addresses.length > 1) debug(`${config.ifname} has multiple ipv4 - ${JSON.stringify(addresses)}. choosing the first one.`);
+
+    return addresses[0];
+}
+
+async function getIPv6(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 IPv6 address`);
+    if (addresses.length > 1) debug(`${config.ifname} has multiple ipv6 - ${JSON.stringify(addresses)}. choosing the first one.`);
+
+    return addresses[0];
+}
+
+async function testIPv4Config(config) {
+    assert.strictEqual(typeof config, 'object');
+
+    if (typeof config.ifname !== 'string') return new BoxError(BoxError.BAD_FIELD, 'ifname is not a string');
+
+    const [error] = await safe(getIPv4(config));
+    return error || null;
+}
+
+async function testIPv6Config(config) {
+    assert.strictEqual(typeof config, 'object');
+
+    if (typeof config.ifname !== 'string') return new BoxError(BoxError.BAD_FIELD, 'ifname is not a string');
+
+    const [error] = await safe(getIPv6(config));
+    return error || null;
+}