Acquire Internet IP from Libp2p API

[317787106]

Rationale

At present, java-tron clients obtain external IPv4 and IPv6 through a method that accesses two certain URLs, it’s the same as libp2p. Java-tron executes this method first, and libp2p executes later when being initialized. This time-consuming method has been executed twice and may delay the startup speed of the java-tron clients.

Implementation

1. When java-tron clients start, it obtains the external IP through Libp2p’s method/api directly.
2. When initializing libp2p, java-tron assigns two IPs to the related fields of P2pConfig, and Libp2p does not need to acquire the external IP again. To meet this requirement we need to add a new constructor method for libp2p.

Compatibility

There is no backward compatibility concern for this issue.

[halibobo1205]

What is the purpose of external IPv4 and IPv6? What are the effects if they are not acquired ?

[317787106]

@halibobo1205 The main usage of ip in libp2p is used to construct your homenode, that is part of UDP Ping & Pong message sent to other in p2p node discovering, and you can find third party nodes from neighbours's message that include ip. Usage of ip in java-tron is to build HelloMessage in HandshakeService.

[tomatoishealthy]

Why not initial the libp2p module first, and try to get the IPs through the libp2p interface?

[eodiandie]

Why not initial the libp2p module first, and try to get the IPs through the libp2p interface?

agree with @guoquanwu , if java-tron's use libp2p module as a dependency, it is better to query the needed config directly from the dependency instead of constructing it itself.

[kuny0707]

Why not initial the libp2p module first, and try to get the IPs through the libp2p interface?

same viewpoint with this. Using Libp2p’s method/api directly to get the external IP and then reusing the IP to initial libp2p may be unreasonable.

[317787106]

@guoquanwu @xq-lu @yuekun0707 Good suggestion! I accept this idea. There will be more places to modify, but that is another matter.

[halibobo1205]

@halibobo1205 The main usage of ip in libp2p is used to construct your homenode, that is part of UDP Ping & Pong message sent to other in p2p node discovering, and you can find third party nodes from neighbours's message that include ip. Usage of ip in java-tron is to build HelloMessage in HandshakeService.

BTW, what are the effects if they are acquired failed?

[317787106]

@halibobo1205 If java-tron fails to get the external IP, it use 127.0.0.1 as default, it records HelloMessage in log. When some exception happens, developer can backtrack the whole process easily. But this will become harder if ip is missing or use default ip in HelloMessage. Node in HelloMessage includes IPv4 and IPv6, so it has more information than the socket's address.

[lurais]

What if the ip changed after you acquired it ? How much time does it cost to obtain external IPv4 and IPv6? As I know, it should be very fast to obtain external IPv4 and IPv6