ZeroConf is a protocol that helps us advertising a service or discovering the available services in our networks. This is how Chromecast works, but why don’t we go deeper? - What is ZeroConf – Why is it needed – Discovery VS Advertising – What are the different implementations that we can find on Android – And on server side? – Small demo and code show

1. IT’S ZEROCONF
Bonjour Android
Roberto Orgiu
Giuseppe Mariniello
Android Developer
Backend Developer

2. WHAT IS ZEROCONF?

3. “ZERO-CONFIGURATION NETWORKING IS A SET OF
TECHNOLOGIES THAT AUTOMATICALLY CREATES A USABLE
COMPUTER NETWORK BASED ON THE INTERNET PROTOCOL
SUITE (TCP/IP) WHEN COMPUTERS OR NETWORK
PERIPHERALS ARE INTERCONNECTED.“
WHAT IS ZEROCONF

4. WHAT IS ZEROCONF
“IT DOES NOT REQUIRE MANUAL
OPERATOR INTERVENTION OR SPECIAL
CONFIGURATION SERVERS.“

5. WHERE CAN WE FIND
ZEROCONF?

6. ALMOST EVERYWHERE

7. BONJOUR ANDROID, IT’S ZEROCONF
THINK “DIFFERENT”
▸ ZeroConf is a standard
▸ UPnP/DLNA are somehow similar, but different people and ideas
▸ Apple has its own implementation, called Bonjour (once Rendezvous)
▸ On Android, we have very different solutions for using it

8. APPLE OFTEN REFERS TO ZEROCONF AS
BONJOUR, GIVING THEIR OWN
DEFINITION OF THE CONCEPTS
BONJOUR ANDROID, IT’S ZEROCONF
FUN FACT

9. Wut? Why do you even…?

10. BONJOUR ANDROID, IT’S ZEROCONF
HOW DOES IT WORK?
Ehy! I am 192.168.1.50
and I have the service
DroidConService running
on port 56472!
Great! Exactly what I was looking for!

11. BONJOUR ANDROID, IT’S ZEROCONF
▸ No infrastructure needed
▸ Simplicity over scalability
▸ 4 areas: IP interface configuration, translation between host name and IP
address, IP multicast address allocation, service discovery
▸ Aware of network changes
▸ Still a draft
HOW DOES IT WORK?

12. BONJOUR ANDROID, IT’S ZEROCONF
▸ Configure netmask
▸ Allocate unique IP address
IP INTERFACE CONFIGURATION

13. BONJOUR ANDROID, IT’S ZEROCONF
▸ Allows hostnames to be mapped to IP addresses and back
▸ Failure proof with retry mechanism
▸ Conflict detection
TRANSLATION BETWEEN HOST NAME AND IP ADDRESS

14. BONJOUR ANDROID, IT’S ZEROCONF
IP MULTICAST ADDRESS ALLOCATION
▸ List which of the scopes (local, site-local, link-local) are available
▸ Select a multicast address preventing conflicts

15. BONJOUR ANDROID, IT’S ZEROCONF
SERVICE DISCOVERY
▸ Service must be discoverable via identifier and/or type
▸ Discovery without the use of a service-specific protocol and should complete in
a timely manner (10s of seconds)
▸ Prompt detection of new services in a timely manner (10s of seconds)
D
R
A
F
T

16. BONJOUR ANDROID, IT’S ZEROCONF
HOW DOES IT WORK?
▸ Each part must start with _ (underscore)
▸ The second part only allows _tcp or _udp
_ServiceType._TransportProtocolName.
List of common services goo.gl/EXh1g

17. BONJOUR ANDROID, IT’S ZEROCONF
WHAT ABOUT ANDROID?
▸ API FROM 4.1
▸ JMDNS FOR JAVA
▸ APPLE NATIVE (C++) IMPLEMENTATION

18. BONJOUR ANDROID, IT’S ZEROCONF
JMDNS FOR JAVA
▸ Easy to implement
▸ Runs on the main thread, unless we specify otherwise
▸ Distributed as JAR or via Maven repo
▸ Long start-up time
▸ Compatible with all the Android versions

19. BONJOUR ANDROID, IT’S ZEROCONF
WHAT ABOUT ANDROID?
▸ API FROM 4.1
▸ JMDNS FOR JAVA
▸ APPLE NATIVE (C++) IMPLEMENTATION

20. BONJOUR ANDROID, IT’S ZEROCONF
APPLE NATIVE (C++) IMPLEMENTATION
▸ Ported to Android by Apple
▸ Open-sourced
▸ Needs Android NDK
▸ Few projects come with it already packed in
▸ Short startup time
▸ More complex logic

21. BONJOUR ANDROID, IT’S ZEROCONF
WHAT ABOUT ANDROID?
▸ API FROM 4.1
▸ JMDNS FOR JAVA
▸ APPLE NATIVE (C++) IMPLEMENTATION

22. BONJOUR ANDROID, IT’S ZEROCONF
ANDROID API
▸ From Android 4.1, custom attributes added with 5.1 (API 21)
▸ Already asynchronous, with return on the main thread
▸ Verbose, but easy to implement
▸ Based on two steps: discovery and resolution
▸ Only one service can be resolved at a time
http://developer.android.com/training/connect-devices-wirelessly/nsd.html

23. BONJOUR ANDROID, IT’S ZEROCONF
ANDROID API - SERVER
NsdServiceInfo serviceInfo = new NsdServiceInfo();
serviceInfo.setServiceName("DroidConService");
serviceInfo.setServiceType("_http._tcp.");
serviceInfo.setPort(randomPort);
nsdManager = Context.getSystemService(Context.NSD_SERVICE);
nsdManager.registerService(serviceInfo,
NsdManager.PROTOCOL_DNS_SD, mRegistrationListener);
Remember to unregister the service upon app closing!

24. BONJOUR ANDROID, IT’S ZEROCONF
ANDROID API - CLIENT
class Resolver extends NsdManager.ResolveListener {
@Override
public void onResolveFailed(NsdServiceInfo serviceInfo, int errorCode) {}
@Override
public void onServiceResolved(NsdServiceInfo serviceInfo) {
// here we can use our resolved service
}
};
Resolve resolveListener = new Resolve();

25. BONJOUR ANDROID, IT’S ZEROCONF
ANDROID API - CLIENT
class Resolver extends NsdManager.ResolveListener {
@Override
public void onResolveFailed(NsdServiceInfo serviceInfo, int errorCode) {}
@Override
public void onServiceResolved(NsdServiceInfo serviceInfo) {
// here we can use our resolved service
}
};
Resolve resolveListener = new Resolve();

26. BONJOUR ANDROID, IT’S ZEROCONF
ANDROID API - CLIENT
class SimpleDiscoveryListener extends NsdManager.DiscoveryListener {
@Override public void onDiscoveryStarted(String regType) {}
@Override public void onServiceFound(NsdServiceInfo service) {
if (service.getServiceName().contains(“DroidConService")){
nsdManager.resolveService(service, resolveListener);
}
}
@Override public void onServiceLost(NsdServiceInfo service) {}
@Override public void onDiscoveryStopped(String serviceType) {}
@Override public void onStartDiscoveryFailed(String serviceType, int errorCode) {
nsdManager.stopServiceDiscovery(this);
}
@Override public void onStopDiscoveryFailed(String serviceType, int errorCode) {
nsdManager.stopServiceDiscovery(this);
}};

27. BONJOUR ANDROID, IT’S ZEROCONF
ANDROID API - CLIENT
class SimpleDiscoveryListener extends NsdManager.DiscoveryListener {
@Override public void onDiscoveryStarted(String regType) {}
@Override public void onServiceFound(NsdServiceInfo service) {
if (service.getServiceName().contains(“DroidConService")){
nsdManager.resolveService(service, resolveListener);
}
}
@Override public void onServiceLost(NsdServiceInfo service) {}
@Override public void onDiscoveryStopped(String serviceType) {}
@Override public void onStartDiscoveryFailed(String serviceType, int errorCode) {
nsdManager.stopServiceDiscovery(this);
}
@Override public void onStopDiscoveryFailed(String serviceType, int errorCode) {
nsdManager.stopServiceDiscovery(this);
}};

28. BONJOUR ANDROID, IT’S ZEROCONF
ANDROID API - CLIENT
SimpleDiscoveryListener discoveryListener = new SimpleDiscoveryListener();
nsdManager.discoverServices(SERVICE_TYPE,
NsdManager.PROTOCOL_DNS_SD, discoveryListener);
nsdManager.stopServiceDiscovery(discoveryListener);

29. BONJOUR ANDROID, IT’S ZEROCONF
ANDROID API - CLIENT
SimpleDiscoveryListener discoveryListener = new SimpleDiscoveryListener();
nsdManager.discoverServices(SERVICE_TYPE,
NsdManager.PROTOCOL_DNS_SD, discoveryListener);
nsdManager.stopServiceDiscovery(discoveryListener);

30. ARE THERE BETTER
WAYS OF DOING IT?

31. YES, THERE ARE!
ARE THERE BETTER WAYS OF DOING IT

32. BONJOUR ANDROID, IT’S ZEROCONF
BETTER WAYS OF DOING IT
▸ better-zeroconf
▸ RxDNSSD
▸ RxBonjour
▸ ZeRxConf
▸ android-mdns
▸ JmDNS
▸ Apple mDNS
▸ Apple mDNS
▸ JmDNS + Android Native APIs
▸ Apple mDNS

33. DEMO TIME!

34. Q & A
CHECK THE REPO @ GITHUB.COM/ENNOVA-IT/DROIDCON-DEMO

35. BONJOUR ANDROID, IT’S ZEROCONF
THANKS FOR WATCHING!