socket.bind() + bound address becomes unavailable + query = indefinite hang

[timbowhite]

BTW thanks for this module.

If you socket.bind() to a local address, and then the interface becomes unavailable (ie. network goes down, network interface no longer available, cable unplugged, etc), and you then run a query, the query will hang indefinitely.

Example:

'use strict';

const dnsSocket = require('.')
const socket = dnsSocket({retries: 0, timeout: 5000});

// bind to some local address, 192.168.0.2 in this case, adjust accordingly
new Promise(function (fulfill, reject){
    socket.on('error', reject);
    socket.on('listening', fulfill);
    socket.bind(null, '192.168.0.2');
})
// do something like unplug your network cable
// to make the bound address --> EADDRNOTAVAIL 
.then(function(){
    console.log('socket bound');
    console.log('to reproduce, kill your network connection within the next 5 seconds');
    return new Promise(function(resolve, reject) {
        setTimeout(resolve, 5000);
    });
})
// make a query, it'll hang indefinitely
.then(function(){
    console.log('making socket query, should hang indefinitely');
    return new Promise(function(resolve, reject) {
        socket.query({
              questions: [{
                type: 'A',
                name: 'google.com'
              }]
            },
            53,
            '1.1.1.1',
            function(err, res){
                if (err) return reject(err);
                resolve(res);
            }
        );
    });
})
.then(function(res){
    console.log('got response', res);
    console.log('all done, destroy socket');
    socket.destroy();
})
.catch(function(err){
    console.log('caught error', err);
    socket.destroy();
});

Output:

socket bound
to reproduce, kill your network connection within the next 5 seconds
making socket query, should hang indefinitely

To reproduce, you'll need to:

1. replace '192.168.0.2' with your local IP address
2. unplug your network cable/kill your network connection when prompted

I think I see the issue, PR incoming.

[timbowhite]

Nevermind this issue, it can probably be closed :) I didn't wait long enough. dns-socket was still doing retries under the hood and it did eventually time out, even though I did specify 0 retries, 0 is falsey, and thus in the options will still default to 5, i.e:

const socket = dnsSocket({retries: 0, timeout: 5000});

and

this.retries = opts.retries || 0

I'll submit a PR that immediately fails if socket.send() callback has an error, but no worries if you'd prefer not to merge it.

[silverwind]

Option parsing should be improved to support a 0 value on numeric values. Not sure I agree with immediately failing on socket.send, some errors should be retried, some not, but it's not really easy to distinguish. I'd rather walk on the safe side and retry always.