= Basic Net types for Golang
brent saner <bts@r00t2.io>
Last updated {localdatetime}
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WARNING: This part of `sysutils` is not finished. Work will resume later.

This "submodule/subpackage" (such a thing technically doesn't exist in Golang) is a collection of data taken directly from IANA's https://www.iana.org/protocols[database^] that contains populated ports
footnote:[https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml[Service Name and Transport Protocol Port Number Registry^]] and
protocolsfootnote:[https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml[Protocol Numbers^]].

You probably don't want to use anything in this parent directory (`r00t2.io/sysutils/net`), as it's only used to generate the data from the IANA's registries.

== Ports

You can specify your own port via several methods.

=== The long way

[source,go]
----
package main

import (
	`fmt`
	
	`r00t2.io/sysutils/net/ports`
	`r00t2.io/sysutils/net/protos`
)

func main() {
	var p *ports.IPPort

	p = &ports.IPPort{
		Number: 22,
		Protocol: &protos.IPProto{
			Name: "TCP",
			Number: 6,
			Reference: "[RFC793]",
			Reserved: false,
			Description: "Transmission Control",
			IP6ExtensionHeader: false,
		},
		ServiceName: "SSH",
		Description: "Secure Shell",
		Reserved:    false,
	}
	
	fmt.Printf(
		"Port:\n" +
		"\tNumber: %v\n" +
		"\tProto: %v\n" +
		"\tService: %v\n" +
		"\tDesc: %v\n" +
		"\tReserved?: %v\n",
		p.Number, p.Proto.Name, p.ServiceName, p.Description, p.Reserved)
}
----

=== The Shorter Way

[source,go]
----
package main

import (
	`fmt`
	`log`

	`r00t2.io/sysutils/net/ports`
	`r00t2.io/sysutils/net/protos`
)

func main() {
	var proto *protos.IPProto
	var port *ports.IPPort
	var err error

	proto = &protos.IPProto{Name: "TCP"}
	port = &ports.IPPort{Number:22, Protocol: &proto}
	// Populate recurses down into Protocol as well.
	if err = port.Populate(); err != nil {
		log.Panic(err)
	}

    fmt.Printf(
    	"Port:\n" +
        "\tNumber: %v\n" +
        "\tProto: %v\n" +
        "\tService: %v\n" +
        "\tDesc: %v\n" +
        "\tReserved?: %v\n",
        port.Number, port.Proto.Name, port.ServiceName, port.Description, port.Reserved)
}
----

=== The "Gotta Go Fast" Way

[source,go]
----
package main

import (
	`fmt`
	`log`

	`r00t2.io/sysutils/net/ports`
)

func main() {
	var err error
	var port *ports.IPPort

	// The default protocol is "TCP".
	// If a UDP service is found but no TCP for the given port number, UDP is used.
	if err = port.FetchNum(22); err != nil {
		log.Panic(err)
	}

    // If you need to specify a protocol (by name) - e.g. it isn't TCP, use FetchNumProto.
	port.FetchNumProto(22, "TCP")

	fmt.Printf("%#v\n", port)

}
----

== Protocols

You can specify your own protocol via several methods.

=== The long way

[source,go]
----
package main

import (
	`fmt`

	`r00t2.io/sysutils/net/protos`
)

func main() {
	var p *protos.IPProto

	p = &protos.IPProto{
			Name: "TCP",
			Number: 6,
			Reference: "[RFC793]",
			Description: "Transmission Control",
			Reserved: false,
			IP6ExtensionHeader: false,
	}

	fmt.Printf(
		"Protocol:\n" +
		"\tName: %v\n" +
		"\tNumber: %v\n" +
		"\tReference: %v\n" +
		"\tReserved?: %v\n" +
		"\tIPv6 Extension Header?: %v\n",
		p.Name, p.Number, p.Reference, p.Reserved, p.IP6ExtensionHeader)
}
----

=== The Shorter Way

[source,go]
----
package main

import (
	`fmt`
	`log`

	`r00t2.io/sysutils/net/protos`
)

func main() {
	var proto *protos.IPProto
	var err error

	proto = &protos.IPProto{Name: "TCP"}
	if err = proto.Populate(); err != nil {
		log.Panic(err)
	}

	fmt.Printf(
		"Protocol:\n" +
		"\tName: %v\n" +
		"\tNumber: %v\n" +
		"\tReference: %v\n" +
		"\tReserved?: %v\n" +
		"\tIPv6 Extension Header?: %v\n",
		p.Name, p.Number, p.Reference, p.Reserved, p.IP6ExtensionHeader)
}
----

=== The "Gotta Go Fast" Way

[source,go]
----
package main

import (
	`fmt`
	`log`

	`r00t2.io/sysutils/net/protos`
)

func main() {
	var err error
	var proto *protos.IPProto

	if err = proto.FetchName("TCP"); err != nil {
		log.Panic(err)
	}

	if err = port.FetchNum(6); err != nil {
		log.Panic(err)
	}

    fmt.Printf("%#v\n", proto)

}
----
