go-pfcp

PFCP implementation in Golang.

What is PFCP?

PFCP(Packet Forwarding Control Protocol) is a signaling protocol used in mobile networking infrastructure(LTE EPC, 5GC) to realize CUPS architecture(Control and User Plane Separation, not a printing system) defined in 3GPP TS29.244.

Are you looking for a GTP implementation in Golang? go-gtp would be the right choice for you :P

Project Status

This project is still WIP.
Implementation of all the messages and IEs defined in TS29.244 V16.7.0(2021-04) has been done, but the exported APIs may still be updated in the future, as they are not tested enough (we add a new tag in that case).

We are now working on implementing networking functionalities (like setting up associations, establish sessions with easy & quick APIs), as well as updating the messages and IE definitions according to the latest specifications.

Getting Started

Installation

go-pfcp supports Go Modules. Just run go mod tidy in your project's directory to collect the required packages automatically.

go mod tidy

Running examples

Exchanging Heartbeat

Small heartbeat client and server examples are available under examples/heartheat. The client sends HeartbeatRequest, and the server responds with HeartbeatResponse.

1. run server first,

By default, the server listens on loopback. It can be specified explicitly by the -s flag.

go-pfcp/examples/heartbeat/hb-server$ go run main.go
2019/12/22 20:03:31 waiting for messages to come on: 127.0.0.2:8805

2. then run client,

By default, the client sends a Heartbeat to loopback. It can be specified explicitly by the -s flag. It exits after printing the timestamp in Heartbeat Response from the server.

go-pfcp/examples/heartbeat/hb-client$ go run main.go
2019/12/22 20:03:36 sent Heartbeat Request to: 127.0.0.2:8805
2019/12/22 20:03:36 got Heartbeat Response with TS: 2019-12-22 20:03:36 +0900 JST, from: 127.0.0.2:8805
go-pfcp/examples/heartbeat/hb-client$
go-pfcp/examples/heartbeat/hb-client$ go run main.go
2019/12/22 20:03:40 sent Heartbeat Request to: 127.0.0.2:8805
2019/12/22 20:03:40 got Heartbeat Response with TS: 2019-12-22 20:03:40 +0900 JST, from: 127.0.0.2:8805

3. and see the outcome on server

It starts listening again after responding to the client.

go-pfcp/examples/heartbeat/hb-server$ go run main.go
2019/12/22 20:03:31 waiting for messages to come on: 127.0.0.2:8805
2019/12/22 20:03:36 got Heartbeat Request with TS: 2019-12-22 20:03:36 +0900 JST, from: 127.0.0.1:47305
2019/12/22 20:03:36 sent Heartbeat Response to: 127.0.0.1:47305
2019/12/22 20:03:36 waiting for messages to come on: 127.0.0.2:8805
2019/12/22 20:03:40 got Heartbeat Request with TS: 2019-12-22 20:03:40 +0900 JST, from: 127.0.0.1:55395
2019/12/22 20:03:40 sent Heartbeat Response to: 127.0.0.1:55395
2019/12/22 20:03:40 waiting for messages to come on: 127.0.0.2:8805
^Csignal: interrupt

Supported Features

Messages

PFCP Node related messages

PFCP Session related messages

Information Elements

All the IEs are of the same type: ie.IE.

Constructors are available for every type of IEs.
To create CreatePDR IE, use NewCreatePDR(). Parameters for those constructors are implemented as friendly for Gophers as possible. See ie/ie_test.go for detailed (and working) usage.

// returned type and parameters in NewCreatePDR() are all *ie.IE.
createPDR := ie.NewCreatePDR(
    ie.NewPDRID(0xffff),
    ie.NewPrecedence(0x11111111),
    ie.NewPDI(
        ie.NewSourceInterface(ie.SrcInterfaceAccess),
        ie.NewFTEID(0x01, 0x11111111, net.ParseIP("127.0.0.1"), nil, 0),
        ie.NewNetworkInstance("some.instance.example"),
        ie.NewRedundantTransmissionParametersInPDI(
            ie.NewFTEID(0x01, 0x11111111, net.ParseIP("127.0.0.1"), nil, 0),
            ie.NewNetworkInstance("some.instance.example"),
        ),
        ie.NewUEIPAddress(0x02, "127.0.0.1", "", 0),
        ie.NewTrafficEndpointID(0x01),
        ie.NewSDFFilter("aaaaaaaa", "bb", "cccc", "ddd", 0xffffffff),
        ie.NewApplicationID("https://github.com/wmnsk/go-pfcp/"),
        ie.NewEthernetPDUSessionInformation(0x01),
        ie.NewEthernetPacketFilter(
            ie.NewEthernetFilterID(0xffffffff),
            ie.NewEthernetFilterProperties(0x01),
            ie.NewMACAddress(mac1, mac2, mac3, mac4),
            ie.NewEthertype(0xffff),
            ie.NewCTAG(0x07, 1, 1, 4095),
            ie.NewSTAG(0x07, 1, 1, 4095),
            ie.NewSDFFilter("aaaaaaaa", "bb", "cccc", "ddd", 0xffffffff),
        ),
    ),
    ie.NewOuterHeaderRemoval(0x01, 0x02),
    ie.NewFARID(0xffffffff),
    ie.NewURRID(0xffffffff),
    ie.NewQERID(0xffffffff),
    ie.NewActivatePredefinedRules("go-pfcp"),
    ie.NewActivationTime(time.Date(2019, time.January, 1, 0, 0, 0, 0, time.UTC)),
    ie.NewDeactivationTime(time.Date(2019, time.January, 1, 0, 0, 0, 0, time.UTC)),
    ie.NewMARID(0x1111),
    ie.NewPacketReplicationAndDetectionCarryOnInformation(0x0f),
    ie.NewIPMulticastAddressingInfo(
        ie.NewIPMulticastAddress(net.ParseIP("127.0.0.1"), nil, net.ParseIP("127.0.0.1"), nil),
        ie.NewSourceIPAddress(net.ParseIP("127.0.0.1"), nil, 24),
    ),
    ie.NewUEIPAddressPoolIdentity("go-pfcp"),
)

Or just use ie.New() to create an arbitrary IE(when you don't need constructors or you need to create an enterprise-specific one).

ie := ie.New(ieType, enterpriseID, payload)

Values can be retrieved by calling helper methods on *ie.IE. For instance, you can immediately get the value in a string by calling NetworkInstance().

ni := ie.NewNetworkInstance("some.instance.example")

v, err := ni.NetworkInstance()
// returns "some.instance.example" if ni is valid. Otherwise it returns error.

For complex IEs like F-TEID, <IE-name> method returns <IE-name>Fields structure.

fteid := ie.NewFTEID(0x01, 0x11111111, net.ParseIP("127.0.0.1"), nil, nil)

f, err := fteid.FTEID()
// returns FTEIDFields struct which contains values in its fields.

teid := f.TEID // has TEID as uint32
v4 := f.IPv4Address // has IPv4 address as net.IP

On grouped IEs, the value (or custom fields) can be retrieved by directly calling such methods.

createPDR := ie.NewCreatePDR(
    ie.NewPDRID(0xffff),
    // ...
)

v, err := createPDR.PDRID()
// returns 0xffff if createPDR contains PDRID and it is valid. Otherwise it returns error.

List of implemented IEs

IEs are (basically) implemented in conformance with TS29.244 V16.3.1(2020-04).

Author(s)

Yoshiyuki Kurauchi (Website / LinkedIn)

I'm always open to welcome co-authors! Please feel free to talk to me.

LICENSE

MIT