jackpal / go-nat-pmp Goto Github PK

The current test only works if the test machine has networking executables installed, so that the gateway library can find the default gateway, and only if there is a NAT-PMP server on the default gateway.

Can we test some portion of this code without either of those things?

Getting this error from AddPortMapping. Curious if anyone has seen it before or knows what it means.

Non-zero result code 3

It would be nice to have support for PCP, which is the successor of NAT-PMP (basically NAT-PMP v1).

PCP basically extends NAT-PMP to be able to control stateful firewalls (IPv4 or IPv6), without necessarily involving NAT. Stateful firewalls are the real issue when applications need incoming connectivity (especially in an IPv6 world), NAT is just an artifact of the limited IPv4 address space.

From RFC 6886:

In 2013, NAT-PMP was superseded by the IETF Standards Track Port
Control Protocol [RFC6887].  PCP builds on NAT-PMP and uses a
compatible packet format, and adds a number of significant
enhancements, including IPv6 support, management of outbound
mappings, management of firewall rules, full compatibility with
large-scale NATs with a pool of external addresses, error lifetimes,
and an extension mechanism to enable future enhancements.

The on-wire format and UDP ports are the same, and there is support to facilitate the interoperability between the two protocols, see: https://tools.ietf.org/html/rfc6887#page-87

Hello,
I am using your library and the function GetExternalAddress() is not returning an error but it isn't returning a proper result either, it just gets stuck at that part of my program.

	gatewayIP, err := gateway.DiscoverGateway()
	if err != nil {
		log.Fatalln("Can't discover gateway: " + err.Error())
	} else {
		client := natpmp.NewClient(gatewayIP)
		fmt.Println("Created a new client!")
		address, err := client.GetExternalAddress()
		if err != nil {
			log.Fatalln("Can't get external address: " + err.Error())
		} 
	}

The file torrent/gateway.go has a neat DiscoverGateway() function that could be included in this package.

I understand that this function may not always work, but could not it be included in this package?

It could be made such that if you provide natpmp.NewClient with the argument nil, it would try to guess. Does it make sense?

Pro of removing dependency: decouples the two libraries.
Con of removing dependency: breaks existing clients. (of which there are very few.)

In the README you are linking to a draft version: https://tools.ietf.org/html/draft-cheshire-nat-pmp-03

The final version is: https://tools.ietf.org/html/rfc6886

Two questions:

• can/will you fix this? (should I send a PR?)
• does this library implement the draft or the final version (sorry.. I haven't check whether there actually are any differences..)?