diam

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 Go to latest Published: Aug 24, 2014 License: BSD-3-Clause Imports: 17 Imported by: 0

Documentation

Overview

Package go-diameter provides support for the Diameter protocol for Go. See RFC 6733.

go-diameter is minimalist implementation of the Diameter base protocol, organized in sub-packages with specific functionality:

  • diam: the main package, provides the capability of encoding and decoding messages, and a client and server API similar to net/http.

  • diam/avp: implementation of Diameter attribute-value-pairs.

  • diam/avp/format: AVP data formats (e.g. Unsigned32, OctetString).

  • diam/dict: a dictionary parser that supports collections of dictionaries.

  • diam/util: utilities for our sub-packages.

If you're looking to go right into code, see the examples subdirectory for applications like clients and servers.

Diameter Applications

All diameter applications require at least the following:

  • A dictionary with the application id, its commands and message formats
  • A program that implements the application, driven by the dictionary

The diam/dict sub-package supports the base application (id 0, RFC 6733) and the credit control application (id 4, RFC 4006). Each application has its own commands and messages, and their pre-defined AVPs.

AVP data have specific formats, like UTF8String, Unsigned32 and so on. Fortunately, those types map align well with Go types, which makes things easier for us. However, the AVP data formats have specific properties like padding for certain strings, which have to be taken care of. The sub-package diam/avp/format handles it all.

At last, the diam package is used to build clients and servers using an API very similar to the one of net/http. To initiate the client or server, you'll have to pass a dictionary. Messages sent and received are encoded and decoded using the dictionary automatically.

The API of clients and servers require that you assign handlers for certain messages, similar to how you route HTTP endpoints. In the handlers, you'll receive messages already decoded.

Index

Constants

View Source 
const (
	MultiRoundAuth         = 1001
	Success                = 2001
	LimitedSuccess         = 2002
	CommandUnsupported     = 3001
	UnableToDeliver        = 3002
	RealmNotServed         = 3003
	TooBusy                = 3004
	LoopDetected           = 3005
	RedirectIndication     = 3006
	ApplicationUnsupported = 3007
	InvalidHDRBits         = 3008
	InvalidAVPBits         = 3009
	UnknownPeer            = 3010
	AuthenticationRejected = 4001
	OutOfSpace             = 4002
	ElectionLost           = 4003
	AVPUnsupported         = 5001
	UnknownSessionId       = 5002
	AuthorizationRejected  = 5003
	InvalidAVPValue        = 5004
	MissingAVP             = 5005
	ResourcesExceeded      = 5006
	ContradictingAVPs      = 5007
	AVPNotAllowed          = 5008
	AVPOccursTooManyTimes  = 5009
	NoCommonApplication    = 5010
	UnsupportedVersion     = 5011
	UnableToComply         = 5012
	InvalidBitInHeader     = 5013
	InvalidAVPLenght       = 5014
	InvalidMessageLength   = 5015
	InvalidAVPBitCombo     = 5016
	NoCommonSecurity       = 5017
)

Diameter result codes.

View Source 
const (
	AbortSession         = 274
	Accounting           = 271
	CapabilitiesExchange = 257
	CreditControl        = 272
	DeviceWatchdog       = 280
	DisconnectPeer       = 282
	ReAuth               = 258
	SessionTermination   = 275
)
View Source 
const (
	RequestFlag       = 1 << 7
	ProxiableFlag     = 1 << 6
	ErrorFlag         = 1 << 5
	RetransmittedFlag = 1 << 4
)

Command flags.

View Source 
const GroupedAVPFormat = 50 // Must not conflict with other format.DataFormatId.
View Source 
const HeaderLength = 20 // Diameter header length.

Variables

View Source 
var DefaultServeMux = NewServeMux()

DefaultServeMux is the default ServeMux used by Serve.

Functions

func ErrorReports 

func ErrorReports() chan ErrorReport

ErrorReport returns the ErrorReport channel of the DefaultServeMux.

func Handle 

func Handle(cmd string, handler Handler)

Handle registers the handler for the given pattern in the DefaultServeMux.

func HandleFunc 

func HandleFunc(cmd string, handler func(Conn, *Message))

HandleFunc registers the handler function for the given command in the DefaultServeMux.

func ListenAndServe 

func ListenAndServe(addr string, handler Handler, dp *dict.Parser) error

ListenAndServe listens on the TCP network address addr and then calls Serve with handler to handle requests on incoming connections.

If handler is nil, diam.DefaultServeMux is used.

If dict is nil, dict.Default is used.

func ListenAndServeTLS 

func ListenAndServeTLS(addr string, certFile string, keyFile string, handler Handler, dp *dict.Parser) error

ListenAndServeTLS acts identically to ListenAndServe, except that it expects SSL connections. Additionally, files containing a certificate and matching private key for the server must be provided. If the certificate is signed by a certificate authority, the certFile should be the concatenation of the server's certificate followed by the CA's certificate.

One can use generate_cert.go in crypto/tls to generate cert.pem and key.pem.

func Serve 

func Serve(l net.Listener, handler Handler) error

Serve accepts incoming diameter connections on the listener l, creating a new service goroutine for each. The service goroutines read messages and then call handler to reply to them. Handler is typically nil, in which case the DefaultServeMux is used.

Types

type AVP 

type AVP struct {
	Code     uint32        // Code of this AVP
	Flags    uint8         // Flags of this AVP
	Length   int           // Length of this AVP's payload
	VendorId uint32        // VendorId of this AVP
	Data     format.Format // Data of this AVP (payload)
}

Diameter AVP.

func DecodeAVP 

func DecodeAVP(data []byte, application uint32, dictionary *dict.Parser) (*AVP, error)

Decode decodes the bytes of a Diameter AVP. It uses the given application id and dictionary for decoding the bytes.

func NewAVP 

func NewAVP(code uint32, flags uint8, vendor uint32, data format.Format) *AVP

NewAVP creates and initializes a new AVP.

func (*AVP) DecodeFromBytes 

func (a *AVP) DecodeFromBytes(data []byte, application uint32, dictionary *dict.Parser) error

DecodeFromBytes decodes the bytes of a Diameter AVP. It uses the given application id and dictionary for decoding the bytes.

func (*AVP) Len 

func (a *AVP) Len() int

func (*AVP) Serialize 

func (a *AVP) Serialize() ([]byte, error)

Serialize returns the byte sequence that represents this AVP. It requires at least the Code, Flags and Data fields set.

func (*AVP) SerializeTo 

func (a *AVP) SerializeTo(b []byte) error

func (*AVP) String 

func (a *AVP) String() string

type CloseNotifier 

type CloseNotifier interface {
	// CloseNotify returns a channel that is closed
	// when the client connection has gone away.
	CloseNotify() <-chan struct{}
}

The CloseNotifier interface is implemented by Conns which allow detecting when the underlying connection has gone away.

This mechanism can be used to detect if the client has disconnected.

type Conn 

type Conn interface {
	Write(b []byte) (int, error) // Writes a msg to the connection
	Close()                      // Close the connection
	LocalAddr() net.Addr         // Local IP
	RemoteAddr() net.Addr        // Remote IP
	TLS() *tls.ConnectionState   // or nil when not using TLS
}

Conn interface is used by a handler to send diameter messages.

func Dial 

func Dial(addr string, handler Handler, dp *dict.Parser) (Conn, error)

Dial connects to the peer pointed to by addr and returns the Conn that can be used to send diameter messages. Incoming messages are handled by the handler, which is tipically nil and DefaultServeMux is used. If dict is nil, dict.Default is used.

func DialTLS 

func DialTLS(addr, certFile, keyFile string, handler Handler, dp *dict.Parser) (Conn, error)

DialTLS is the same as Dial, but for TLS.

type ErrorReport 

type ErrorReport struct {
	Message *Message
	Error   error
}

ErrorReport is sent out of the server in case it fails to read messages because of a bad dictionary, or due to network errors.

type GroupedAVP 

type GroupedAVP struct {
	AVP []*AVP
}

GroupedAVP that is different from the dummy format.Grouped.

func DecodeGrouped 

func DecodeGrouped(data format.Grouped, application uint32, dictionary *dict.Parser) (*GroupedAVP, error)

func (*GroupedAVP) Format 

func (g *GroupedAVP) Format() format.FormatId

func (*GroupedAVP) Len 

func (g *GroupedAVP) Len() int

func (*GroupedAVP) Padding 

func (g *GroupedAVP) Padding() int

func (*GroupedAVP) Serialize 

func (g *GroupedAVP) Serialize() []byte

func (*GroupedAVP) String 

func (g *GroupedAVP) String() string

type Handler 

type Handler interface {
	ServeDIAM(Conn, *Message)
	ErrorReports() chan ErrorReport
}

Objects implementing the Handler interface can be registered to serve particular messages like CER, DWR.

ServeDIAM should write messages to the Conn and then return. Returning signals that the request is finished and that the server can move on to the next request on the connection.

type HandlerFunc 

type HandlerFunc func(Conn, *Message)

The HandlerFunc type is an adapter to allow the use of ordinary functions as diameter handlers. If f is a function with the appropriate signature, HandlerFunc(f) is a Handler object that calls f.

func (HandlerFunc) ErrorReports 

func (f HandlerFunc) ErrorReports() chan ErrorReport

ErrorReports calls f.ErrorReports()

func (HandlerFunc) ServeDIAM 

func (f HandlerFunc) ServeDIAM(c Conn, m *Message)

ServeDIAM calls f(c, m). 

type Header struct {
	Version       uint8
	MessageLength uint32
	CommandFlags  uint8
	CommandCode   uint32
	ApplicationId uint32
	HopByHopId    uint32
	EndToEndId    uint32
}

Diameter Header.

func DecodeHeader 

func DecodeHeader(data []byte) (*Header, error)

DecodeHeader decodes the bytes of a Diameter Header.

func (*Header) DecodeFromBytes 

func (h *Header) DecodeFromBytes(data []byte) error

DecodeFromBytes decodes the bytes of a Diameter Header.

func (*Header) Serialize 

func (h *Header) Serialize() []byte

func (*Header) SerializeTo 

func (h *Header) SerializeTo(b []byte)

SerializeTo serializes the header to a byte sequence in network byte order.

func (*Header) String 

func (h *Header) String() string

type Message 

type Message struct {
	Header *Header
	AVP    []*AVP

	Dictionary *dict.Parser // Used to encode and decode AVPs.
}

Diameter message.

func NewMessage 

func NewMessage(cmd uint32, flags uint8, appid, hopbyhop, endtoend uint32, dictionary *dict.Parser) *Message

NewMessage creates and initializes Message.

func NewRequest 

func NewRequest(cmd uint32, appid uint32, dictionary *dict.Parser) *Message

NewRequest is an alias to NewMessage.

func ReadMessage 

func ReadMessage(reader io.Reader, dictionary *dict.Parser) (*Message, error)

ReadMessage returns a Message. It uses the dictionary to parse the binary stream from the reader.

func (*Message) AddAVP 

func (m *Message) AddAVP(a *AVP)

AddAVP adds the AVP to the Message.

func (*Message) Answer 

func (m *Message) Answer(resultCode uint32) *Message

Answer creates an answer for the current Message with an embedded Result-Code AVP.

func (*Message) FindAVP 

func (m *Message) FindAVP(code interface{}) (*AVP, error)

FindAVP searches the Message for a specific AVP. The code can be either the AVP code (int, uint32) or name (string).

Example: 

avp, err := m.FindAVP(264)
avp, err := m.FindAVP("Origin-Host")

func (*Message) Len 

func (m *Message) Len() int

func (*Message) NewAVP 

func (m *Message) NewAVP(code interface{}, flags uint8, vendor uint32, data format.Format) (*AVP, error)

NewAVP creates and initializes a new AVP and adds it to the Message.

func (*Message) Serialize 

func (m *Message) Serialize() []byte

func (*Message) SerializeTo 

func (m *Message) SerializeTo(b []byte)

func (*Message) String 

func (m *Message) String() string

func (*Message) Unmarshal 

func (m *Message) Unmarshal(dst interface{}) error

Unmarshal stores the result of a diameter message in the struct pointed to by dst.

Unmarshal can not only decode AVPs into the struct, but also their Go equivalent data types, directly.

For example: 

type CER struct {
	OriginHost  AVP    `avp:"Origin-Host"`
	.. or
	OriginHost  *AVP   `avp:"Origin-Host"`
	.. or
	OriginHost  string `avp:"Origin-Host"`
}
var d CER
err := diam.Unmarshal(&d)

This decodes the Origin-Host AVP as three different types. The first, AVP, makes a copy of the AVP in the message and stores in the struct. The second, *AVP, stores a pointer to the original AVP in the message. If you change the values of it, you're actually changing the message. The third decodes the inner contents of AVP.Data, which in this case is a format.DiameterIdentity, and stores the value of it in the struct.

Unmarshal supports all the basic Go types, including slices, for multiple AVPs of the same type) and structs, for grouped AVPs.

Slices: 

type CER struct {
	Vendors  []*AVP `avp:"Supported-Vendor-Id"`
}
var d CER
err := diam.Unmarshal(&d)

Slices have the same principles of other types. If they're of type []*AVP it'll store references in the struct, while []AVP makes copies and []int (or []string, etc) decodes the AVP data for you.

Grouped AVPs: 

type VSA struct {
	AuthAppId int `avp:"Auth-Application-Id"`
	VendorId  int `avp:"Vendor-Id"`
}
type CER struct {
	VSA VSA  `avp:"Vendor-Specific-Application-Id"`
	.. or
	VSA *VSA `avp:"Vendor-Specific-Application-Id"`
	.. or
	VSA struct {
		AuthAppId int `avp:"Auth-Application-Id"`
		VendorId  int `avp:"Vendor-Id"`
	} `avp:"Vendor-Specific-Application-Id"`
}
var d CER
err := m.Unmarshal(&d)

Other types are supported as well, such as net.IP and time.Time where applicable. See the format sub-package for details. Usually, you want to decode values to their native Go type when the AVPs don't have to be re-used in an answer, such as Origin-Host and friends. The ones that are usually added to responses, such as Origin-State-Id are better decoded to just AVP or *AVP, making it easier to re-use them in the answer.

Note that decoding values to *AVP is much faster and more efficient than decoding to AVP or the native Go types.

func (*Message) WriteTo 

func (m *Message) WriteTo(writer io.Writer) (int64, error)

type ServeMux 

type ServeMux struct {
	// contains filtered or unexported fields
}

ServeMux is a diameter message multiplexer. It matches the command from the incoming message against a list of registered commands and calls the handler.

func NewServeMux 

func NewServeMux() *ServeMux

NewServeMux allocates and returns a new ServeMux.

func (*ServeMux) ErrorReports 

func (mux *ServeMux) ErrorReports() chan ErrorReport

ErrorReports returns the ErrorReport channel of the handler.

func (*ServeMux) Handle 

func (mux *ServeMux) Handle(cmd string, handler Handler)

Handle registers the handler for the given code. If a handler already exists for code, Handle panics.

func (*ServeMux) HandleFunc 

func (mux *ServeMux) HandleFunc(cmd string, handler func(Conn, *Message))

HandleFunc registers the handler function for the given command. Special cmd "ALL" may be used as a catch all.

func (*ServeMux) ServeDIAM 

func (mux *ServeMux) ServeDIAM(c Conn, m *Message)

ServeDIAM dispatches the request to the handler whose code match the incoming message, or close the connection if no handler is found.

type Server 

type Server struct {
	Addr         string        // TCP address to listen on, ":3868" if empty
	Handler      Handler       // handler to invoke, diam.DefaultServeMux if nil
	Dict         *dict.Parser  // diameter dictionaries for this server
	ReadTimeout  time.Duration // maximum duration before timing out read of the request
	WriteTimeout time.Duration // maximum duration before timing out write of the response
	TLSConfig    *tls.Config   // optional TLS config, used by ListenAndServeTLS
}

A Server defines parameters for running a diameter server.

func (*Server) ListenAndServe 

func (srv *Server) ListenAndServe() error

ListenAndServe listens on the TCP network address srv.Addr and then calls Serve to handle requests on incoming connections. If srv.Addr is blank, ":3868" is used.

func (*Server) ListenAndServeTLS 

func (srv *Server) ListenAndServeTLS(certFile, keyFile string) error

ListenAndServeTLS listens on the TCP network address srv.Addr and then calls Serve to handle requests on incoming TLS connections.

Filenames containing a certificate and matching private key for the server must be provided. If the certificate is signed by a certificate authority, the certFile should be the concatenation of the server's certificate followed by the CA's certificate.

If srv.Addr is blank, ":3868" is used.

func (*Server) Serve 

func (srv *Server) Serve(l net.Listener) error

Serve accepts incoming connections on the Listener l, creating a new service goroutine for each. The service goroutines read requests and then call srv.Handler to reply to them.

Source Files

View all Source files

Directories

Path Synopsis
avp
Diameter AVP codes and flags.
 Diameter AVP codes and flags.
format
Diameter AVP data formats.
 Diameter AVP data formats.
Diameter dictionary parser.
 Diameter dictionary parser.
Utilities to support our sub-packages.
 Utilities to support our sub-packages.

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