stun

package module
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 Go to latest Published: Jul 12, 2018 License: BSD-3-Clause Imports: 18 Imported by: 0

README

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STUN

Package stun implements Session Traversal Utilities for NAT (STUN) [RFC 5389] with no external dependencies and focuses on speed. See example or stun server for usage.

RFCs

The package aims to implement the follwing RFCs. Note that the requirement status is based on the WebRTC spec, focusing on data channels for now.

rfc status requirement description
RFC5389 status status Session Traversal Utilities for NAT
IPv6 status status IPv6 support
(TLS-over-)TCP status status Sending over TCP or TLS-over-TCP
ALTERNATE-SERVER status status ALTERNATE-SERVER Mechanism

Example

You can get your current IP address from any STUN server by sending binding request. See more idiomatic example at cmd/stun-client.

package main

import (
	"fmt"
	"time"

	"github.com/gortc/stun"
)

func main() {
	// Creating a "connection" to STUN server.
	c, err := stun.Dial("udp", "stun.l.google.com:19302")
	if err != nil {
		panic(err)
	}
	deadline := time.Now().Add(time.Second * 5)
	// Bulding binding request with random transaction id.
	message := stun.MustBuild(stun.TransactionID, stun.BindingRequest)
	// Sending request to STUN server, waiting for response message.
	if err := c.Do(message, deadline, func(res stun.Event) {
		if res.Error != nil {
			panic(res.Error)
		}
		// Decoding XOR-MAPPED-ADDRESS attribute from message.
		var xorAddr stun.XORMappedAddress
		if err := xorAddr.GetFrom(res.Message); err != nil {
			panic(err)
		}
		fmt.Println("your IP is", xorAddr.IP)
	}); err != nil {
		panic(err)
	}
}

Stability

Package is currently approaching beta stage, API should be fairly stable and implementation is almost complete. Bug reports are welcome.

Additional attributes are unlikely to be implemented in scope of stun package, the only exception is constants for attribute or message types.

RFC 3489 notes

RFC 5389 obsoletes RFC 3489, so implementation was ignored by purpose, however, RFC 3489 can be easily implemented as separate package.

Requirements

Go 1.9.2 is currently supported and tested in CI. Should work on 1.8, 1.7, and tip.

Benchmarks

Intel(R) Core(TM) i7-8700K:

goos: linux
goarch: amd64
pkg: github.com/gortc/stun
PASS
benchmark                                          iter       time/iter      throughput   bytes alloc        allocs
---------                                          ----       ---------      ----------   -----------        ------
BenchmarkMappedAddress_AddTo-12              1000000000     22.90 ns/op                        0 B/op   0 allocs/op
BenchmarkAlternateServer_AddTo-12            1000000000     23.00 ns/op                        0 B/op   0 allocs/op
BenchmarkAgent_GC-12                           10000000   2217.00 ns/op                        0 B/op   0 allocs/op
BenchmarkAgent_Process-12                     300000000     52.80 ns/op                        0 B/op   0 allocs/op
BenchmarkMessage_GetNotFound-12              3000000000      4.13 ns/op                        0 B/op   0 allocs/op
BenchmarkClient_Do-12                          30000000    495.00 ns/op                        0 B/op   0 allocs/op
BenchmarkErrorCode_AddTo-12                   300000000     41.10 ns/op                        0 B/op   0 allocs/op
BenchmarkErrorCodeAttribute_AddTo-12          500000000     30.90 ns/op                        0 B/op   0 allocs/op
BenchmarkErrorCodeAttribute_GetFrom-12       2000000000      7.84 ns/op                        0 B/op   0 allocs/op
BenchmarkFingerprint_AddTo-12                 300000000     46.60 ns/op     944.52 MB/s        0 B/op   0 allocs/op
BenchmarkFingerprint_Check-12                 500000000     37.20 ns/op    1397.50 MB/s        0 B/op   0 allocs/op
BenchmarkBuildOverhead/Build-12               100000000    133.00 ns/op                        0 B/op   0 allocs/op
BenchmarkBuildOverhead/BuildNonPointer-12     100000000    262.00 ns/op                      100 B/op   4 allocs/op
BenchmarkBuildOverhead/Raw-12                 100000000    119.00 ns/op                        0 B/op   0 allocs/op
BenchmarkMessageIntegrity_AddTo-12             20000000   1058.00 ns/op      18.89 MB/s      480 B/op   6 allocs/op
BenchmarkMessageIntegrity_Check-12             20000000   1023.00 ns/op      31.27 MB/s      480 B/op   6 allocs/op
BenchmarkMessage_Write-12                    1000000000     16.10 ns/op    1734.19 MB/s        0 B/op   0 allocs/op
BenchmarkMessageType_Value-12               10000000000      0.23 ns/op                        0 B/op   0 allocs/op
BenchmarkMessage_WriteTo-12                  2000000000      8.19 ns/op                        0 B/op   0 allocs/op
BenchmarkMessage_ReadFrom-12                 1000000000     18.00 ns/op    1108.32 MB/s        0 B/op   0 allocs/op
BenchmarkMessage_ReadBytes-12                2000000000     10.50 ns/op    1896.39 MB/s        0 B/op   0 allocs/op
BenchmarkIsMessage-12                       10000000000      0.64 ns/op   31241.13 MB/s        0 B/op   0 allocs/op
BenchmarkMessage_NewTransactionID-12           50000000    385.00 ns/op                        0 B/op   0 allocs/op
BenchmarkMessageFull-12                       100000000    134.00 ns/op                        0 B/op   0 allocs/op
BenchmarkMessageFullHardcore-12               300000000     52.70 ns/op                        0 B/op   0 allocs/op
BenchmarkMessage_WriteHeader-12              3000000000      5.21 ns/op                        0 B/op   0 allocs/op
BenchmarkUsername_AddTo-12                   1000000000     14.60 ns/op                        0 B/op   0 allocs/op
BenchmarkUsername_GetFrom-12                 2000000000     11.70 ns/op                        0 B/op   0 allocs/op
BenchmarkNonce_AddTo-12                      1000000000     20.00 ns/op                        0 B/op   0 allocs/op
BenchmarkNonce_AddTo_BadLength-12             300000000     49.40 ns/op                       32 B/op   1 allocs/op
BenchmarkNonce_GetFrom-12                    2000000000     11.80 ns/op                        0 B/op   0 allocs/op
BenchmarkUnknownAttributes/AddTo-12          1000000000     18.50 ns/op                        0 B/op   0 allocs/op
BenchmarkUnknownAttributes/GetFrom-12        1000000000     13.40 ns/op                        0 B/op   0 allocs/op
BenchmarkXOR-12                              1000000000     14.00 ns/op   73071.52 MB/s        0 B/op   0 allocs/op
BenchmarkXORSafe-12                           100000000    102.00 ns/op    9945.44 MB/s        0 B/op   0 allocs/op
BenchmarkXORFast-12                          1000000000     13.60 ns/op   75332.68 MB/s        0 B/op   0 allocs/op
BenchmarkXORMappedAddress_AddTo-12            500000000     35.20 ns/op                        0 B/op   0 allocs/op
BenchmarkXORMappedAddress_GetFrom-12         1000000000     22.30 ns/op                        0 B/op   0 allocs/op
ok  	github.com/gortc/stun	698.712s

Development goals

stun package is low-level core gortc module, so security, efficiency (both memory and cpu), simplicity, code quality, and low dependencies are paramount goals.

Documentation

Overview

Package stun implements Session Traversal Utilities for NAT (STUN) RFC 5389.

The stun package is intended to use by package that implements extension to STUN (e.g. TURN) or client/server applications.

Most methods are designed to be zero allocations. If it is not enough, low-level methods are available. On other hand, there are helpers that reduce code repeat.

See examples for Message for basic usage, or https://github.com/ernado/turn package for example of stun extension implementation.

Index

Examples

Constants

View Source 
const (
	DefaultPort    = 3478
	DefaultTLSPort = 5349
)

IANA assigned ports for "stun" protocol.

View Source 
const (

	// TransactionIDSize is length of transaction id array (in bytes).
	TransactionIDSize = 12 // 96 bit
)

Variables

View Source 
var (
	// ErrTransactionStopped indicates that transaction was manually stopped.
	ErrTransactionStopped = errors.New("transaction is stopped")
	// ErrTransactionNotExists indicates that agent failed to find transaction.
	ErrTransactionNotExists = errors.New("transaction not exists")
	// ErrTransactionExists indicates that transaction with same id is already
	// registered.
	ErrTransactionExists = errors.New("transaction exists with same id")
)
View Source 
var (
	// Binding request message type.
	BindingRequest = NewType(MethodBinding, ClassRequest)
	// Binding success response message type
	BindingSuccess = NewType(MethodBinding, ClassSuccessResponse)
	// Binding error response message type.
	BindingError = NewType(MethodBinding, ClassErrorResponse)
)

Common STUN message types.

View Source 
var ErrAgentClosed = errors.New("agent is closed")

ErrAgentClosed indicates that agent is in closed state and is unable to handle transactions.

View Source 
var ErrAttributeNotFound = errors.New("attribute not found")

ErrAttributeNotFound means that attribute with provided attribute type does not exist in message.

View Source 
var ErrBadIPLength = errors.New("invalid length of IP value")

ErrBadIPLength means that len(IP) is not net.{IPv6len,IPv4len}.

View Source 
var ErrBadUnknownAttrsSize = errors.New("bad UNKNOWN-ATTRIBUTES size")

ErrBadUnknownAttrsSize means that UNKNOWN-ATTRIBUTES attribute value has invalid length.

View Source 
var ErrClientClosed = errors.New("client is closed")

ErrClientClosed indicates that client is closed.

View Source 
var ErrClientNotInitialized = errors.New("client not initialized")

ErrClientNotInitialized means that client connection or agent is nil.

View Source 
var ErrDecodeToNil = errors.New("attempt to decode to nil message")

ErrDecodeToNil occurs on Decode(data, nil) call.

View Source 
var ErrFingerprintBeforeIntegrity = errors.New(
	"FINGERPRINT before MESSAGE-INTEGRITY attribute",
)

ErrFingerprintBeforeIntegrity means that FINGEPRINT attribute is already in message, so MESSAGE-INTEGRITY attribute cannot be added.

View Source 
var ErrNoConnection = errors.New("no connection provided")

ErrNoConnection means that ClientOptions.Connection is nil.

View Source 
var ErrNoDefaultReason = errors.New("no default reason for ErrorCode")

ErrNoDefaultReason means that default reason for provided error code is not defined in RFC.

View Source 
var ErrTransactionTimeOut = errors.New("transaction is timed out")

ErrTransactionTimeOut indicates that transaction has reached deadline.

View Source 
var ErrUnexpectedHeaderEOF = errors.New("unexpected EOF: not enough bytes to read header")

ErrUnexpectedHeaderEOF means that there were not enough bytes in m.Raw to read header.

Functions

func Decode added in v0.3.0 

func Decode(data []byte, m *Message) error

Decode decodes Message from data to m, returning error if any.

func FingerprintValue added in v0.3.0 

func FingerprintValue(b []byte) uint32

FingerprintValue returns CRC-32 of b XOR-ed by 0x5354554e.

The value of the attribute is computed as the CRC-32 of the STUN message up to (but excluding) the FINGERPRINT attribute itself, XOR'ed with the 32-bit value 0x5354554e (the XOR helps in cases where an application packet is also using CRC-32 in it).

func IsMessage added in v0.3.0 

func IsMessage(b []byte) bool

IsMessage returns true if b looks like STUN message. Useful for multiplexing. IsMessage does not guarantee that decoding will be successful.

func NewTransactionID added in v0.3.0 

func NewTransactionID() (b [TransactionIDSize]byte)

NewTransactionID returns new random transaction ID using crypto/rand as source.

Types

type Agent added in v0.3.0 

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

Agent is low-level abstraction over transaction list that handles concurrency (all calls are goroutine-safe) and time outs (via Collect call).

func NewAgent added in v0.3.0 

func NewAgent(o AgentOptions) *Agent

NewAgent initializes and returns new Agent from options.

func (*Agent) Close added in v0.3.0 

func (a *Agent) Close() error

Close terminates all transactions with ErrAgentClosed and renders Agent to closed state.

func (*Agent) Collect added in v0.3.0 

func (a *Agent) Collect(gcTime time.Time) error

Collect terminates all transactions that have deadline before provided time, blocking until all handlers will process ErrTransactionTimeOut. Will return ErrAgentClosed if agent is already closed.

It is safe to call Collect concurrently but makes no sense.

func (*Agent) Process added in v0.3.0 

func (a *Agent) Process(m *Message) error

Process incoming message, picking handler by transaction id. If transaction is not registered, zero handler is used. If default handle is not provided, message is silently ignored. Call blocks until handler returns.

func (*Agent) Start added in v0.3.0 

func (a *Agent) Start(id [TransactionIDSize]byte, deadline time.Time, h Handler) error

Start registers transaction with provided id, deadline and callback. Could return ErrAgentClosed, ErrTransactionExists. Callback f is guaranteed to be eventually called. See AgentFn for callback processing constraints.

func (*Agent) Stop added in v0.3.0 

func (a *Agent) Stop(id [TransactionIDSize]byte) error

Stop stops transaction by id with ErrTransactionStopped, blocking until callback returns.

func (*Agent) StopWithError added in v0.3.0 

func (a *Agent) StopWithError(id [TransactionIDSize]byte, err error) error

StopWithError removes transaction from list and calls transaction callback with provided error. Can return ErrTransactionNotExists and ErrAgentClosed.

type AgentOptions added in v1.5.1 

type AgentOptions struct {
	Handler Handler // Default handler, can be nil.
}

AgentOptions are required to initialize Agent.

type AlternateServer added in v0.3.0 

type AlternateServer struct {
	IP   net.IP
	Port int
}

AlternateServer represents ALTERNATE-SERVER attribute.

RFC 5389 Section 15.11

func (*AlternateServer) AddTo added in v0.3.0 

func (s *AlternateServer) AddTo(m *Message) error

AddTo adds ALTERNATE-SERVER attribute to message.

func (*AlternateServer) GetFrom added in v0.3.0 

func (s *AlternateServer) GetFrom(m *Message) error

GetFrom decodes ALTERNATE-SERVER from message.

type AttrLengthErr added in v1.5.1 

type AttrLengthErr struct {
	Attr     AttrType
	Got      int
	Expected int
}

AttrLengthErr means that length for attribute is invalid.

func (AttrLengthErr) Error added in v1.5.1 

func (e AttrLengthErr) Error() string

type AttrOverflowErr added in v1.5.1 

type AttrOverflowErr struct {
	Type AttrType
	Max  int
	Got  int
}

AttrOverflowErr occurs when len(v) > Max.

func (AttrOverflowErr) Error added in v1.5.1 

func (e AttrOverflowErr) Error() string

type AttrType 

type AttrType uint16

AttrType is attribute type. 

const (
	AttrMappedAddress     AttrType = 0x0001 // MAPPED-ADDRESS
	AttrUsername          AttrType = 0x0006 // USERNAME
	AttrMessageIntegrity  AttrType = 0x0008 // MESSAGE-INTEGRITY
	AttrErrorCode         AttrType = 0x0009 // ERROR-CODE
	AttrUnknownAttributes AttrType = 0x000A // UNKNOWN-ATTRIBUTES
	AttrRealm             AttrType = 0x0014 // REALM
	AttrNonce             AttrType = 0x0015 // NONCE
	AttrXORMappedAddress  AttrType = 0x0020 // XOR-MAPPED-ADDRESS
)

Attributes from comprehension-required range (0x0000-0x7FFF). 

const (
	AttrSoftware        AttrType = 0x8022 // SOFTWARE
	AttrAlternateServer AttrType = 0x8023 // ALTERNATE-SERVER
	AttrFingerprint     AttrType = 0x8028 // FINGERPRINT
)

Attributes from comprehension-optional range (0x8000-0xFFFF). 

const (
	AttrPriority       AttrType = 0x0024 // PRIORITY
	AttrUseCandidate   AttrType = 0x0025 // USE-CANDIDATE
	AttrICEControlled  AttrType = 0x8029 // ICE-CONTROLLED
	AttrICEControlling AttrType = 0x802A // ICE-CONTROLLING
)

Attributes from RFC 5245 ICE. 

const (
	AttrChannelNumber      AttrType = 0x000C // CHANNEL-NUMBER
	AttrLifetime           AttrType = 0x000D // LIFETIME
	AttrXORPeerAddress     AttrType = 0x0012 // XOR-PEER-ADDRESS
	AttrData               AttrType = 0x0013 // DATA
	AttrXORRelayedAddress  AttrType = 0x0016 // XOR-RELAYED-ADDRESS
	AttrEvenPort           AttrType = 0x0018 // EVEN-PORT
	AttrRequestedTransport AttrType = 0x0019 // REQUESTED-TRANSPORT
	AttrDontFragment       AttrType = 0x001A // DONT-FRAGMENT
	AttrReservationToken   AttrType = 0x0022 // RESERVATION-TOKEN
)

Attributes from RFC 5766 TURN. 

const (
	AttrOrigin AttrType = 0x802F
)

Attributes from An Origin Attribute for the STUN Protocol.

func (AttrType) String 

func (t AttrType) String() string

func (AttrType) Value added in v0.3.0 

func (t AttrType) Value() uint16

Value returns uint16 representation of attribute type.

type Attributes added in v0.3.0 

type Attributes []RawAttribute

Attributes is list of message attributes.

func (Attributes) Get added in v0.3.0 

func (a Attributes) Get(t AttrType) (RawAttribute, bool)

Get returns first attribute from list by the type. If attribute is present the RawAttribute is returned and the boolean is true. Otherwise the returned RawAttribute will be empty and boolean will be false.

type CRCMismatch added in v1.3.1 

type CRCMismatch struct {
	Expected uint32
	Actual   uint32
}

CRCMismatch represents CRC check error.

func (CRCMismatch) Error added in v1.3.1 

func (m CRCMismatch) Error() string

type Checker added in v0.3.0 

type Checker interface {
	Check(m *Message) error
}

Checker checks *Message attribute.

type Client 

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

Client simulates "connection" to STUN server.

func Dial added in v0.3.0 

func Dial(network, address string) (*Client, error)

Dial connects to the address on the named network and then initializes Client on that connection, returning error if any.

func NewClient 

func NewClient(options ClientOptions) (*Client, error)

NewClient initializes new Client from provided options, starting internal goroutines and using default options fields if necessary. Call Close method after using Client to release resources.

func (*Client) Close 

func (c *Client) Close() error

Close stops internal connection and agent, returning CloseErr on error.

func (*Client) Do added in v0.3.0 

func (c *Client) Do(m *Message, d time.Time, f func(Event)) error

Do is Start wrapper that waits until callback is called. If no callback provided, Indicate is called instead.

Do has cpu overhead due to blocking, see BenchmarkClient_Do. Use Start method for less overhead.

func (*Client) Indicate added in v0.3.0 

func (c *Client) Indicate(m *Message) error

Indicate sends indication m to server. Shorthand to Start call with zero deadline and callback.

func (*Client) Start added in v0.3.0 

func (c *Client) Start(m *Message, d time.Time, h Handler) error

Start starts transaction (if f set) and writes message to server, handler is called asynchronously.

type ClientAgent added in v0.3.0 

type ClientAgent interface {
	Process(*Message) error
	Close() error
	Start(id [TransactionIDSize]byte, deadline time.Time, f Handler) error
	Stop(id [TransactionIDSize]byte) error
	Collect(time.Time) error
}

ClientAgent is Agent implementation that is used by Client to process transactions.

type ClientOptions added in v1.5.1 

type ClientOptions struct {
	Agent       ClientAgent
	Connection  Connection
	TimeoutRate time.Duration // defaults to 100 ms
}

ClientOptions are used to initialize Client.

type CloseErr added in v0.3.0 

type CloseErr struct {
	AgentErr      error
	ConnectionErr error
}

CloseErr indicates client close failure.

func (CloseErr) Error added in v0.3.0 

func (c CloseErr) Error() string

type Connection added in v0.3.0 

type Connection interface {
	io.Reader
	io.Writer
	io.Closer
}

Connection wraps Reader, Writer and Closer interfaces.

type DecodeErr added in v0.3.0 

type DecodeErr struct {
	Place   DecodeErrPlace
	Message string
}

DecodeErr records an error and place when it is occurred.

func (DecodeErr) Error added in v0.3.0 

func (e DecodeErr) Error() string

func (DecodeErr) IsInvalidCookie added in v0.3.0 

func (e DecodeErr) IsInvalidCookie() bool

IsInvalidCookie returns true if error means that magic cookie value is invalid.

func (DecodeErr) IsPlace added in v0.3.0 

func (e DecodeErr) IsPlace(p DecodeErrPlace) bool

IsPlace reports if error place is p.

func (DecodeErr) IsPlaceChildren added in v0.3.0 

func (e DecodeErr) IsPlaceChildren(c string) bool

IsPlaceChildren reports if error place children is c.

func (DecodeErr) IsPlaceParent added in v0.3.0 

func (e DecodeErr) IsPlaceParent(p string) bool

IsPlaceParent reports if error place parent is p.

type DecodeErrPlace added in v0.3.0 

type DecodeErrPlace struct {
	Parent   string
	Children string
}

DecodeErrPlace records a place where error is occurred.

func (DecodeErrPlace) String added in v0.3.0 

func (p DecodeErrPlace) String() string

type ErrorCode 

type ErrorCode int

ErrorCode is code for ERROR-CODE attribute. 

const (
	CodeTryAlternate     ErrorCode = 300
	CodeBadRequest       ErrorCode = 400
	CodeUnauthorised     ErrorCode = 401
	CodeUnknownAttribute ErrorCode = 420
	CodeStaleNonce       ErrorCode = 428
	CodeRoleConflict     ErrorCode = 478
	CodeServerError      ErrorCode = 500
)

Possible error codes. 

const (
	CodeForbidden             ErrorCode = 403 // Forbidden
	CodeAllocMismatch         ErrorCode = 437 // Allocation Mismatch
	CodeWrongCredentials      ErrorCode = 441 // Wrong Credentials
	CodeUnsupportedTransProto ErrorCode = 442 // Unsupported Transport Protocol
	CodeAllocQuotaReached     ErrorCode = 486 // Allocation Quota Reached
	CodeInsufficientCapacity  ErrorCode = 508 // Insufficient Capacity
)

Error codes from RFC 5766.

RFC 5766 Section 15

func (ErrorCode) AddTo added in v0.3.0 

func (c ErrorCode) AddTo(m *Message) error

AddTo adds ERROR-CODE with default reason to m. If there is no default reason, returns ErrNoDefaultReason.

type ErrorCodeAttribute added in v0.3.0 

type ErrorCodeAttribute struct {
	Code   ErrorCode
	Reason []byte
}

ErrorCodeAttribute represents ERROR-CODE attribute.

RFC 5389 Section 15.6

func (ErrorCodeAttribute) AddTo added in v0.3.0 

func (c ErrorCodeAttribute) AddTo(m *Message) error

AddTo adds ERROR-CODE to m.

func (*ErrorCodeAttribute) GetFrom added in v0.3.0 

func (c *ErrorCodeAttribute) GetFrom(m *Message) error

GetFrom decodes ERROR-CODE from m. Reason is valid until m.Raw is valid.

func (ErrorCodeAttribute) String added in v0.3.0 

func (c ErrorCodeAttribute) String() string

type Event added in v0.3.0 

type Event struct {
	Message *Message
	Error   error
}

Event is set of arguments passed to AgentFn, describing an transaction event. Do not reuse outside AgentFn.

type FingerprintAttr added in v0.3.0 

type FingerprintAttr byte

FingerprintAttr represents FINGERPRINT attribute.

RFC 5389 Section 15.5 

var Fingerprint FingerprintAttr

Fingerprint is shorthand for FingerprintAttr.

Example: 

m := New()
Fingerprint.AddTo(m)

func (FingerprintAttr) AddTo added in v0.3.0 

func (FingerprintAttr) AddTo(m *Message) error

AddTo adds fingerprint to message.

func (FingerprintAttr) Check added in v0.3.0 

func (FingerprintAttr) Check(m *Message) error

Check reads fingerprint value from m and checks it, returning error if any. Can return *AttrLengthErr, ErrAttributeNotFound, and *CRCMismatch.

type Getter added in v0.3.0 

type Getter interface {
	GetFrom(m *Message) error
}

Getter parses attribute from *Message.

type Handler added in v0.3.0 

type Handler interface {
	// HandleEvent is called on transaction state change.
	// Usage of e is valid only during call, user must
	// copy needed fields explicitly.
	HandleEvent(e Event)
}

Handler handles state changes of transaction.

type HandlerFunc added in v1.6.1 

type HandlerFunc func(e Event)

HandlerFunc is function that implements Handler interface.

func (HandlerFunc) HandleEvent added in v1.6.1 

func (f HandlerFunc) HandleEvent(e Event)

HandleEvent implements Handler.

type IntegrityErr added in v1.3.1 

type IntegrityErr struct {
	Expected []byte
	Actual   []byte
}

IntegrityErr occurs when computed HMAC differs from expected.

func (*IntegrityErr) Error added in v1.3.1 

func (i *IntegrityErr) Error() string

type MappedAddress added in v0.3.0 

type MappedAddress struct {
	IP   net.IP
	Port int
}

MappedAddress represents MAPPED-ADDRESS attribute.

This attribute is used only by servers for achieving backwards compatibility with RFC 3489 clients.

RFC 5389 Section 15.1

func (*MappedAddress) AddTo added in v0.3.0 

func (a *MappedAddress) AddTo(m *Message) error

AddTo adds MAPPED-ADDRESS to message.

func (*MappedAddress) GetFrom added in v0.3.0 

func (a *MappedAddress) GetFrom(m *Message) error

GetFrom decodes MAPPED-ADDRESS from message.

func (MappedAddress) String added in v0.3.0 

func (a MappedAddress) String() string

type Message 

type Message struct {
	Type          MessageType
	Length        uint32 // len(Raw) not including header
	TransactionID [TransactionIDSize]byte
	Attributes    Attributes
	Raw           []byte
}

Message represents a single STUN packet. It uses aggressive internal buffering to enable zero-allocation encoding and decoding, so there are some usage constraints: 

Message, its fields, results of m.Get or any attribute a.GetFrom
are valid only until Message.Raw is not modified.
Example 
buf := new(bytes.Buffer)
m := new(Message)
m.Build(BindingRequest,
	NewTransactionIDSetter([TransactionIDSize]byte{
		1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1,
	}),
	NewSoftware("ernado/stun"),
	NewLongTermIntegrity("username", "realm", "password"),
	Fingerprint,
)
// Instead of calling Build, use AddTo(m) directly for all setters
// to reduce allocations.
// For example:
//	software := NewSoftware("ernado/stun")
//	software.AddTo(m)  // no allocations
// Or pass software as follows:
//	m.Build(&software) // no allocations
// If you pass software as value, there will be 1 allocation.
// This rule is correct for all setters.
fmt.Println(m, "buff length:", len(m.Raw))
n, err := m.WriteTo(buf)
fmt.Println("wrote", n, "err", err)

// Decoding from buf new *Message.
decoded := new(Message)
decoded.Raw = make([]byte, 0, 1024) // for ReadFrom that reuses m.Raw
// ReadFrom does not allocate internal buffer for reading from io.Reader,
// instead it uses m.Raw, expanding it length to capacity.
decoded.ReadFrom(buf)
fmt.Println("has software:", decoded.Contains(AttrSoftware))
fmt.Println("has nonce:", decoded.Contains(AttrNonce))
var software Software
decoded.Parse(&software) // or software.GetFrom(decoded)
// Rule for Parse method is same as for Build.
fmt.Println("software:", software)
if err := Fingerprint.Check(decoded); err == nil {
	fmt.Println("fingerprint is correct")
} else {
	fmt.Println("fingerprint is incorrect:", err)
}
// Checking integrity
i := NewLongTermIntegrity("username", "realm", "password")
if err := i.Check(decoded); err == nil {
	fmt.Println("integrity ok")
} else {
	fmt.Println("integrity bad:", err)
}
fmt.Println("for corrupted message:")
decoded.Raw[22] = 33
fmt.Println("fingerprint:", Fingerprint.Check(decoded))
iErr, ok := i.Check(decoded).(*IntegrityErr)
if ok {
	fmt.Println("integrity check failed")
	fmt.Printf("got:  %x\n", iErr.Actual)
	fmt.Printf("want: %x\n", iErr.Expected)
} else {
	fmt.Println("assertion failed")
}

Output:

binding request l=48 attrs=3 id=AQIDBAUGBwgJAAEA buff length: 68
wrote 68 err <nil>
has software: true
has nonce: false
software: ernado/stun
fingerprint is correct
integrity ok
for corrupted message:
fingerprint: CRC mismatch: b36d2c38 (expected) != 8ef13141 (actual)
integrity check failed
got:  06f0692c159f4256c14b9442927889e341256ac2
want: c1105962efee5c96f4f194cc91b4eb8ab7667c7a

func Build 

func Build(setters ...Setter) (*Message, error)

Build wraps Message.Build method.

func MustBuild added in v0.3.0 

func MustBuild(setters ...Setter) *Message

MustBuild wraps Build call and panics on error.

func New added in v0.3.0 

func New() *Message

New returns *Message with pre-allocated Raw.

func (*Message) Add added in v0.3.0 

func (m *Message) Add(t AttrType, v []byte)

Add appends new attribute to message. Not goroutine-safe.

Value of attribute is copied to internal buffer so it is safe to reuse v.

func (*Message) AddTo added in v0.3.0 

func (m *Message) AddTo(b *Message) error

AddTo sets b.TransactionID to m.TransactionID.

Implements Setter to aid in crafting responses.

func (*Message) Build added in v0.3.0 

func (m *Message) Build(setters ...Setter) error

Build resets message and applies setters to it in batch, returning on first error. To prevent allocations, pass pointers to values.

Example: 

var (
	t        = BindingRequest
	username = NewUsername("username")
	nonce    = NewNonce("nonce")
	realm    = NewRealm("example.org")
)
m := new(Message)
m.Build(t, username, nonce, realm)     // 4 allocations
m.Build(&t, &username, &nonce, &realm) // 0 allocations

See BenchmarkBuildOverhead.

func (*Message) Check added in v0.3.0 

func (m *Message) Check(checkers ...Checker) error

Check applies checkers to message in batch, returning on first error.

func (*Message) CloneTo added in v0.3.0 

func (m *Message) CloneTo(b *Message) error

CloneTo clones m to b securing any further m mutations.

func (*Message) Contains added in v0.3.0 

func (m *Message) Contains(t AttrType) bool

Contains return true if message contain t attribute.

func (*Message) Decode added in v0.3.0 

func (m *Message) Decode() error

Decode decodes m.Raw into m.

func (*Message) Encode added in v0.3.0 

func (m *Message) Encode()

Encode resets m.Raw and calls WriteHeader and WriteAttributes.

func (*Message) Equal added in v0.3.0 

func (m *Message) Equal(b *Message) bool

Equal returns true if Message b equals to m. Ignores m.Raw.

func (*Message) Get added in v0.3.0 

func (m *Message) Get(t AttrType) ([]byte, error)

Get returns byte slice that represents attribute value, if there is no attribute with such type, ErrAttributeNotFound is returned.

func (*Message) NewTransactionID added in v0.3.0 

func (m *Message) NewTransactionID() error

NewTransactionID sets m.TransactionID to random value from crypto/rand and returns error if any.

func (*Message) Parse added in v0.3.0 

func (m *Message) Parse(getters ...Getter) error

Parse applies getters to message in batch, returning on first error.

func (*Message) ReadFrom added in v0.3.0 

func (m *Message) ReadFrom(r io.Reader) (int64, error)

ReadFrom implements ReaderFrom. Reads message from r into m.Raw, Decodes it and return error if any. If m.Raw is too small, will return ErrUnexpectedEOF, ErrUnexpectedHeaderEOF or *DecodeErr.

Can return *DecodeErr while decoding too.

func (*Message) Reset added in v0.3.0 

func (m *Message) Reset()

Reset resets Message, attributes and underlying buffer length.

func (*Message) SetType added in v0.3.0 

func (m *Message) SetType(t MessageType)

SetType sets m.Type and writes it to m.Raw.

func (*Message) String added in v0.3.0 

func (m *Message) String() string

func (*Message) Write added in v0.3.0 

func (m *Message) Write(tBuf []byte) (int, error)

Write decodes message and return error if any.

Any error is unrecoverable, but message could be partially decoded.

func (*Message) WriteAttributes added in v0.3.0 

func (m *Message) WriteAttributes()

WriteAttributes encodes all m.Attributes to m.

func (*Message) WriteHeader added in v0.3.0 

func (m *Message) WriteHeader()

WriteHeader writes header to underlying buffer. Not goroutine-safe.

func (*Message) WriteLength added in v0.3.0 

func (m *Message) WriteLength()

WriteLength writes m.Length to m.Raw. Call is valid only if len(m.Raw) >= 4.

func (*Message) WriteTo added in v0.3.0 

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

WriteTo implements WriterTo via calling Write(m.Raw) on w and returning call result.

func (*Message) WriteTransactionID added in v0.3.0 

func (m *Message) WriteTransactionID()

WriteTransactionID writes m.TransactionID to m.Raw.

func (*Message) WriteType added in v0.3.0 

func (m *Message) WriteType()

WriteType writes m.Type to m.Raw.

type MessageClass 

type MessageClass byte

MessageClass is 8-bit representation of 2-bit class of STUN Message Class. 

const (
	ClassRequest         MessageClass = 0x00 // 0b00
	ClassIndication      MessageClass = 0x01 // 0b01
	ClassSuccessResponse MessageClass = 0x02 // 0b10
	ClassErrorResponse   MessageClass = 0x03 // 0b11
)

Possible values for message class in STUN Message Type.

func (MessageClass) String 

func (c MessageClass) String() string

type MessageIntegrity 

type MessageIntegrity []byte

MessageIntegrity represents MESSAGE-INTEGRITY attribute. AddTo and GetFrom methods will allocate memory for cryptographic functions. Zero-allocation version of MessageIntegrity is not implemented. Implementation and changes to it is subject to security review.

RFC 5389 Section 15.4

func NewLongTermIntegrity added in v0.3.0 

func NewLongTermIntegrity(username, realm, password string) MessageIntegrity

NewLongTermIntegrity returns new MessageIntegrity with key for long-term credentials. Password, username, and realm must be SASL-prepared.

func NewShortTermIntegrity added in v0.3.0 

func NewShortTermIntegrity(password string) MessageIntegrity

NewShortTermIntegrity returns new MessageIntegrity with key for short-term credentials. Password must be SASL-prepared.

func (MessageIntegrity) AddTo added in v0.3.0 

func (i MessageIntegrity) AddTo(m *Message) error

AddTo adds MESSAGE-INTEGRITY attribute to message. Be advised, CPU and allocations costly, can be cause of DOS.

func (MessageIntegrity) Check added in v0.3.0 

func (i MessageIntegrity) Check(m *Message) error

Check checks MESSAGE-INTEGRITY attribute. Be advised, CPU and allocations costly, can be cause of DOS.

func (MessageIntegrity) String added in v0.3.0 

func (i MessageIntegrity) String() string

type MessageType added in v0.3.0 

type MessageType struct {
	Method Method       // e.g. binding
	Class  MessageClass // e.g. request
}

MessageType is STUN Message Type Field.

func NewType added in v0.3.0 

func NewType(method Method, class MessageClass) MessageType

NewType returns new message type with provided method and class.

func (MessageType) AddTo added in v0.3.0 

func (t MessageType) AddTo(m *Message) error

AddTo sets m type to t.

func (*MessageType) ReadValue added in v0.3.0 

func (t *MessageType) ReadValue(v uint16)

ReadValue decodes uint16 into MessageType.

func (MessageType) String added in v0.3.0 

func (t MessageType) String() string

func (MessageType) Value added in v0.3.0 

func (t MessageType) Value() uint16

Value returns bit representation of messageType.

type Method 

type Method uint16

Method is uint16 representation of 12-bit STUN method. 

const (
	MethodBinding          Method = 0x001
	MethodAllocate         Method = 0x003
	MethodRefresh          Method = 0x004
	MethodSend             Method = 0x006
	MethodData             Method = 0x007
	MethodCreatePermission Method = 0x008
	MethodChannelBind      Method = 0x009
)

Possible methods for STUN Message.

func (Method) String 

func (m Method) String() string

type Nonce 

type Nonce []byte

Nonce represents NONCE attribute.

RFC 5389 Section 15.8

func NewNonce added in v0.3.0 

func NewNonce(nonce string) Nonce

NewNonce returns new Nonce from string.

func (Nonce) AddTo added in v0.3.0 

func (n Nonce) AddTo(m *Message) error

AddTo adds NONCE to message.

func (*Nonce) GetFrom added in v0.3.0 

func (n *Nonce) GetFrom(m *Message) error

GetFrom gets NONCE from message.

func (Nonce) String added in v0.3.0 

func (n Nonce) String() string

type RawAttribute 

type RawAttribute struct {
	Type   AttrType
	Length uint16 // ignored while encoding
	Value  []byte
}

RawAttribute is a Type-Length-Value (TLV) object that can be added to a STUN message. Attributes are divided into two types: comprehension-required and comprehension-optional. STUN agents can safely ignore comprehension-optional attributes they don't understand, but cannot successfully process a message if it contains comprehension-required attributes that are not understood.

func (RawAttribute) Equal added in v0.3.0 

func (a RawAttribute) Equal(b RawAttribute) bool

Equal returns true if a == b.

func (RawAttribute) String added in v0.3.0 

func (a RawAttribute) String() string

type Realm 

type Realm []byte

Realm represents REALM attribute.

RFC 5389 Section 15.7

func NewRealm added in v0.3.0 

func NewRealm(realm string) Realm

NewRealm returns Realm with provided value. Must be SASL-prepared.

func (Realm) AddTo added in v0.3.0 

func (n Realm) AddTo(m *Message) error

AddTo adds NONCE to message.

func (*Realm) GetFrom added in v0.3.0 

func (n *Realm) GetFrom(m *Message) error

GetFrom gets REALM from message.

func (Realm) String added in v0.3.0 

func (n Realm) String() string

type Setter added in v0.3.0 

type Setter interface {
	AddTo(m *Message) error
}

Setter sets *Message attribute. 

var TransactionID Setter = transactionIDSetter{}

TransactionID is Setter for m.TransactionID.

func NewTransactionIDSetter added in v0.3.0 

func NewTransactionIDSetter(value [TransactionIDSize]byte) Setter

NewTransactionIDSetter returns new Setter that sets message transaction id to provided value.

type Software 

type Software []byte

Software is SOFTWARE attribute.

RFC 5389 Section 15.10

func NewSoftware added in v0.3.0 

func NewSoftware(software string) Software

NewSoftware returns *Software from string.

func (Software) AddTo added in v0.3.0 

func (s Software) AddTo(m *Message) error

AddTo adds Software attribute to m.

func (*Software) GetFrom added in v0.3.0 

func (s *Software) GetFrom(m *Message) error

GetFrom decodes Software from m.

func (Software) String added in v0.3.0 

func (s Software) String() string

type StopErr added in v0.3.0 

type StopErr struct {
	Err   error // value returned by Stop()
	Cause error // error that caused Stop() call
}

StopErr occurs when Client fails to stop transaction while processing error.

func (StopErr) Error added in v0.3.0 

func (e StopErr) Error() string

type TextAttribute added in v0.3.0 

type TextAttribute []byte

TextAttribute is helper for adding and getting text attributes.

func (TextAttribute) AddToAs added in v0.3.0 

func (v TextAttribute) AddToAs(m *Message, t AttrType, maxLen int) error

AddToAs adds attribute with type t to m, checking maximum length. If maxLen is less than 0, no check is performed.

func (*TextAttribute) GetFromAs added in v0.3.0 

func (v *TextAttribute) GetFromAs(m *Message, t AttrType) error

GetFromAs gets t attribute from m and appends its value to reseted v.

type UnknownAttributes 

type UnknownAttributes []AttrType

UnknownAttributes represents UNKNOWN-ATTRIBUTES attribute.

RFC 5389 Section 15.9

func (UnknownAttributes) AddTo added in v0.3.0 

func (a UnknownAttributes) AddTo(m *Message) error

AddTo adds UNKNOWN-ATTRIBUTES attribute to message.

func (*UnknownAttributes) GetFrom added in v0.3.0 

func (a *UnknownAttributes) GetFrom(m *Message) error

GetFrom parses UNKNOWN-ATTRIBUTES from message.

func (UnknownAttributes) String added in v0.3.0 

func (a UnknownAttributes) String() string

type Username 

type Username []byte

Username represents USERNAME attribute.

RFC 5389 Section 15.3

func NewUsername added in v0.3.0 

func NewUsername(username string) Username

NewUsername returns Username with provided value.

func (Username) AddTo added in v0.3.0 

func (u Username) AddTo(m *Message) error

AddTo adds USERNAME attribute to message.

func (*Username) GetFrom added in v0.3.0 

func (u *Username) GetFrom(m *Message) error

GetFrom gets USERNAME from message.

func (Username) String added in v0.3.0 

func (u Username) String() string

type XORMappedAddress added in v0.3.0 

type XORMappedAddress struct {
	IP   net.IP
	Port int
}

XORMappedAddress implements XOR-MAPPED-ADDRESS attribute.

RFC 5389 Section 15.2

func (XORMappedAddress) AddTo added in v0.3.0 

func (a XORMappedAddress) AddTo(m *Message) error

AddTo adds XOR-MAPPED-ADDRESS to m. Can return ErrBadIPLength if len(a.IP) is invalid.

func (XORMappedAddress) AddToAs added in v0.3.0 

func (a XORMappedAddress) AddToAs(m *Message, t AttrType) error

AddToAs adds XOR-MAPPED-ADDRESS value to m as t attribute.

func (*XORMappedAddress) GetFrom added in v0.3.0 

func (a *XORMappedAddress) GetFrom(m *Message) error

GetFrom decodes XOR-MAPPED-ADDRESS attribute in message and returns error if any. While decoding, a.IP is reused if possible and can be rendered to invalid state (e.g. if a.IP was set to IPv6 and then IPv4 value were decoded into it), be careful.

Example: 

expectedIP := net.ParseIP("213.141.156.236")
expectedIP.String() // 213.141.156.236, 16 bytes, first 12 of them are zeroes
expectedPort := 21254
addr := &XORMappedAddress{
  IP:   expectedIP,
  Port: expectedPort,
}
// addr were added to message that is decoded as newMessage
// ...

addr.GetFrom(newMessage)
addr.IP.String()    // 213.141.156.236, net.IPv4Len
expectedIP.String() // d58d:9cec::ffff:d58d:9cec, 16 bytes, first 4 are IPv4
// now we have len(expectedIP) = 16 and len(addr.IP) = 4.

func (*XORMappedAddress) GetFromAs added in v0.3.0 

func (a *XORMappedAddress) GetFromAs(m *Message, t AttrType) error

GetFromAs decodes XOR-MAPPED-ADDRESS attribute value in message getting it as for t type.

func (XORMappedAddress) String added in v0.3.0 

func (a XORMappedAddress) String() string

Source Files

View all Source files

Directories

Path Synopsis
cmd
stun-client
stun-decode
stun-traversal
internal
hmac
Package hmac implements the Keyed-Hash Message Authentication Code (HMAC) as defined in U.S. Federal Information Processing Standards Publication 198.
 Package hmac implements the Keyed-Hash Message Authentication Code (HMAC) as defined in U.S. Federal Information Processing Standards Publication 198.

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