uasc

package
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 Go to latest Published: Feb 10, 2021 License: MIT Imports: 16 Imported by: 0

Documentation

Overview

Package uasc provides encoding/decoding and automated secure channel and session handling for OPC UA Secure Conversation.

Index

Constants

View Source 
const (
	MessageTypeMessage            = "MSG"
	MessageTypeOpenSecureChannel  = "OPN"
	MessageTypeCloseSecureChannel = "CLO"
)

MessageType definitions.

View Source 
const (
	ChunkTypeIntermediate = 'C'
	ChunkTypeFinal        = 'F'
	ChunkTypeError        = 'A'
)

ChunkType definitions.

View Source 
const (
	MaxTimeout = math.MaxUint32 * time.Millisecond
)

Variables

This section is empty.

Functions

This section is empty.

Types

type AsymmetricSecurityHeader 

type AsymmetricSecurityHeader struct {
	SecurityPolicyURI             string
	SenderCertificate             []byte
	ReceiverCertificateThumbprint []byte
}

AsymmetricSecurityHeader represents a Asymmetric Algorithm Security Header in OPC UA Secure Conversation.

func NewAsymmetricSecurityHeader 

func NewAsymmetricSecurityHeader(uri string, cert, thumbprint []byte) *AsymmetricSecurityHeader

NewAsymmetricSecurityHeader creates a new OPC UA Secure Conversation Asymmetric Algorithm Security Header.

func (*AsymmetricSecurityHeader) Decode 

func (h *AsymmetricSecurityHeader) Decode(b []byte) (int, error)

func (*AsymmetricSecurityHeader) Encode 

func (h *AsymmetricSecurityHeader) Encode() ([]byte, error)

func (*AsymmetricSecurityHeader) Len 

func (h *AsymmetricSecurityHeader) Len() int

Len returns the Header Length in bytes.

func (*AsymmetricSecurityHeader) String 

func (a *AsymmetricSecurityHeader) String() string

String returns Header in string.

type Config 

type Config struct {

	// SecurityPolicyURI is the URI of the Security Policy used to secure the Message.
	// This field is encoded as a UTF-8 string without a null terminator.
	SecurityPolicyURI string

	// Certificate is the X.509 v3 Certificate assigned to the sending application Instance.
	// This is a DER encoded blob.
	// The structure of an X.509 v3 Certificate is defined in X.509 v3.
	// The DER format for a Certificate is defined in X690.
	// This indicates what Private Key was used to sign the MessageChunk.
	// The Stack shall close the channel and report an error to the application if
	// the Certificate is too large for the buffer size supported by the
	// transport layer.
	// This field shall be null if the Message is not signed.
	Certificate []byte

	// LocalKey is a RSA Private Key which will be used to encrypt the OpenSecureChannel
	// messages.  It is the key associated with Certificate
	LocalKey *rsa.PrivateKey

	// Thumbprint is the thumbprint of the X.509 v3 Certificate assigned to the receiving
	// application Instance.
	// The thumbprint is the CertificateDigest of the DER encoded form of the
	// Certificate.
	// This indicates what public key was used to encrypt the MessageChunk.
	// This field shall be null if the Message is not encrypted.
	Thumbprint []byte

	// RemoteCertificate is the X.509 Certificate for the receiving instance.
	// Used to encrypt the message chunks in the OpenSecureChannel phase.
	RemoteCertificate []byte

	// RequestIDSeed is the initial value for RequestID counter in each new SecureChannel
	RequestIDSeed uint32

	// SecurityMode is The type of security to apply to the messages. The type MessageSecurityMode
	// is defined in 7.15.
	// A SecureChannel may have to be created even if the securityMode is NONE. The exact behaviour
	// depends on the mapping used and is described in the Part 6.
	SecurityMode ua.MessageSecurityMode

	// AutoReconnect will make sure that once communication is restored,
	// the old session is used whenever possible and that Susbcription data is not missed.
	// You may choose to use AutoReconnect (true by default) or do it manually.
	// AutoReconnect will make the UaClient to try to reconnect to the server every second,
	// once the communication is broken. If you do it manually, you must be prepared to do it until it succeeds.
	AutoReconnect bool

	// ReconnectInterval is interval duration between each reconnection attempt,
	// ignored if AutoReconnect is set to false.
	ReconnectInterval time.Duration

	// Lifetime is the requested lifetime, in milliseconds, for the new SecurityToken when the
	// SecureChannel works as client. It specifies when the Client expects to renew the SecureChannel
	// by calling the OpenSecureChannel Service again. If a SecureChannel is not renewed, then all
	// Messages sent using the current SecurityTokens shall be rejected by the receiver.
	// Lifetime can also be the revised lifetime, the lifetime of the SecurityToken in milliseconds.
	// The UTC expiration time for the token may be calculated by adding the lifetime to the createdAt time.
	Lifetime uint32

	// RequestTimeout is timeout duration for all synchronous requests over SecureChannel.
	// If the Server doesn't respond within RequestTimeout time, Client returns StatusBadTimeout
	RequestTimeout time.Duration
}

Config represents a configuration which UASC client/server has in common. 

type Header struct {
	MessageType     string
	ChunkType       byte
	MessageSize     uint32
	SecureChannelID uint32
}

Header represents a OPC UA Secure Conversation Header.

func NewHeader 

func NewHeader(msgType string, chunkType byte, chanID uint32) *Header

NewHeader creates a new OPC UA Secure Conversation Header.

func (*Header) Decode 

func (h *Header) Decode(b []byte) (int, error)

func (*Header) Encode 

func (h *Header) Encode() ([]byte, error)

func (*Header) String 

func (h *Header) String() string

String returns Header in string.

type Message 

type Message struct {
	*MessageHeader
	TypeID  *ua.ExpandedNodeID
	Service interface{}
}

Message represents a OPC UA Secure Conversation message.

func (*Message) Decode 

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

func (*Message) Encode 

func (m *Message) Encode() ([]byte, error)

type MessageAbort 

type MessageAbort struct {
	ErrorCode uint32
	Reason    string
}

MessageAbort represents a non-terminal OPC UA Secure Channel error.

Specification: Part6, 7.3

func (*MessageAbort) Decode 

func (m *MessageAbort) Decode(b []byte) (int, error)

func (*MessageAbort) Encode 

func (m *MessageAbort) Encode() ([]byte, error)

func (*MessageAbort) MessageAbort 

func (m *MessageAbort) MessageAbort() string

type MessageChunk 

type MessageChunk struct {
	*MessageHeader
	Data []byte
}

func (*MessageChunk) Decode 

func (m *MessageChunk) Decode(b []byte) (int, error)

type MessageHeader 

type MessageHeader struct {
	*Header
	*AsymmetricSecurityHeader
	*SymmetricSecurityHeader
	*SequenceHeader
}

func (*MessageHeader) Decode 

func (m *MessageHeader) Decode(b []byte) (int, error)

type SecureChannel 

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

func NewSecureChannel 

func NewSecureChannel(endpoint string, c *uacp.Conn, cfg *Config, errCh chan<- error) (*SecureChannel, error)

func (*SecureChannel) Close 

func (s *SecureChannel) Close() error

Close closes an existing secure channel

func (*SecureChannel) EncryptUserPassword 

func (s *SecureChannel) EncryptUserPassword(policyURI, password string, cert, nonce []byte) ([]byte, string, error)

EncryptUserPassword issues a new signature for the client to send in ActivateSessionRequest

func (*SecureChannel) LocalEndpoint 

func (s *SecureChannel) LocalEndpoint() string

func (*SecureChannel) NewSessionSignature 

func (s *SecureChannel) NewSessionSignature(cert, nonce []byte) ([]byte, string, error)

NewSessionSignature issues a new signature for the client to send on the next ActivateSessionRequest

func (*SecureChannel) NewUserTokenSignature 

func (s *SecureChannel) NewUserTokenSignature(policyURI string, cert, nonce []byte) ([]byte, string, error)

NewUserTokenSignature issues a new signature for the client to send in ActivateSessionRequest

func (*SecureChannel) Open 

func (s *SecureChannel) Open(ctx context.Context) error

func (*SecureChannel) Renew 

func (s *SecureChannel) Renew(ctx context.Context) error

func (*SecureChannel) SendRequest 

func (s *SecureChannel) SendRequest(req ua.Request, authToken *ua.NodeID, h func(interface{}) error) error

SendRequest sends the service request and calls h with the response.

func (*SecureChannel) SendRequestWithTimeout 

func (s *SecureChannel) SendRequestWithTimeout(req ua.Request, authToken *ua.NodeID, timeout time.Duration, h func(interface{}) error) error

func (*SecureChannel) VerifySessionSignature 

func (s *SecureChannel) VerifySessionSignature(cert, nonce, signature []byte) error

VerifySessionSignature checks the integrity of a Create/Activate Session response's signature

type SequenceHeader 

type SequenceHeader struct {
	SequenceNumber uint32
	RequestID      uint32
}

SequenceHeader represents a Sequence Header in OPC UA Secure Conversation.

func NewSequenceHeader 

func NewSequenceHeader(seq, req uint32) *SequenceHeader

NewSequenceHeader creates a new OPC UA Secure Conversation Sequence Header.

func (*SequenceHeader) Decode 

func (h *SequenceHeader) Decode(b []byte) (int, error)

func (*SequenceHeader) Encode 

func (h *SequenceHeader) Encode() ([]byte, error)

func (*SequenceHeader) String 

func (s *SequenceHeader) String() string

String returns Header in string.

type SessionConfig 

type SessionConfig struct {
	// AuthenticationToken is the secret Session identifier used to verify that the request is
	// associated with the Session. The SessionAuthenticationToken type is defined in 7.31.
	AuthenticationToken *ua.NodeID

	// ClientDescription is the information that describes the Client application.
	// The type ApplicationDescription is defined in 7.1.
	ClientDescription *ua.ApplicationDescription

	// ServerEndpoints is the list of Endpoints that the Server supports.
	// The Server shall return a set of EndpointDescriptions available for the serverUri
	// specified in the request. The EndpointDescription type is defined in 7.10. The Client
	// shall verify this list with the list from a DiscoveryEndpoint if it used a
	// DiscoveryEndpoint to fetch the EndpointDescriptions.
	// It is recommended that Servers only include the server.applicationUri, endpointUrl,
	// securityMode, securityPolicyUri, userIdentityTokens, transportProfileUri and
	// securityLevel with all other parameters set to null. Only the recommended
	// parameters shall be verified by the client.
	ServerEndpoints []*ua.EndpointDescription

	// LocaleIDs is the list of locale ids in priority order for localized strings. The first
	// LocaleId in the list has the highest priority. If the Server returns a localized string
	// to the Client, the Server shall return the translation with the highest priority that
	// it can. If it does not have a translation for any of the locales identified in this list,
	// then it shall return the string value that it has and include the locale id with the
	// string. See Part 3 for more detail on locale ids. If the Client fails to specify at least
	// one locale id, the Server shall use any that it has.
	// This parameter only needs to be specified during the first call to ActivateSession during
	// a single application Session. If it is not specified the Server shall keep using the
	// current localeIds for the Session.
	LocaleIDs []string

	// UserIdentityToken is the credentials of the user associated with the Client application.
	// The Server uses these credentials to determine whether the Client should be allowed to
	// activate a Session and what resources the Client has access to during this Session.
	// The UserIdentityToken is an extensible parameter type defined in 7.36.
	// The EndpointDescription specifies what UserIdentityTokens the Server shall accept.
	// Null or empty user token shall always be interpreted as anonymous.
	UserIdentityToken interface{}

	// If the Client specified a user identity token that supports digital signatures, then it
	// shall create a signature and pass it as this parameter. Otherwise the parameter is null.
	// The SignatureAlgorithm depends on the identity token type.
	// The SignatureData type is defined in 7.32.
	UserTokenSignature *ua.SignatureData

	// SessionName is an optional name of the session.
	// The default is a unique value for every new session.
	SessionName string

	// If Session works as a client, SessionTimeout is the requested maximum number of milliseconds
	// that a Session should remain open without activity. If the Client fails to issue a Service
	// request within this interval, then the Server shall automatically terminate the Client Session.
	// If Session works as a server, SessionTimeout is an actual maximum number of milliseconds
	// that a Session shall remain open without activity. The Server should attempt to honour the
	// Client request for this parameter,but may negotiate this value up or down to meet its own constraints.
	SessionTimeout time.Duration

	// Stored version of the password to authenticate against a server
	// todo: storing passwords in memory seems wrong
	AuthPassword string

	// PolicyURI to use when encrypting secrets for the User Identity Token
	// Could be different from the secure channel's policy
	AuthPolicyURI string
}

SessionConfig is a set of common configurations used in Session.

type SymmetricSecurityHeader 

type SymmetricSecurityHeader struct {
	TokenID uint32
}

SymmetricSecurityHeader represents a Symmetric Algorithm Security Header in OPC UA Secure Conversation.

func NewSymmetricSecurityHeader 

func NewSymmetricSecurityHeader(token uint32) *SymmetricSecurityHeader

NewSymmetricSecurityHeader creates a new OPC UA Secure Conversation Symmetric Algorithm Security Header.

func (*SymmetricSecurityHeader) Decode 

func (h *SymmetricSecurityHeader) Decode(b []byte) (int, error)

func (*SymmetricSecurityHeader) Encode 

func (h *SymmetricSecurityHeader) Encode() ([]byte, error)

func (*SymmetricSecurityHeader) Len 

func (h *SymmetricSecurityHeader) Len() int

Len returns the Header Length in bytes.

func (*SymmetricSecurityHeader) String 

func (h *SymmetricSecurityHeader) String() string

String returns Header in string.

Source Files

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