Documentation
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Overview ¶
Package gateway parses the wire formats spoken by NMEA 2000 network gateways: the Yacht Devices RAW ASCII line protocol and the Actisense binary stream protocol.
Index ¶
- func EncodeSend(m N2KMessage) ([]byte, error)
- func EncodeStartup() []byte
- func FormatYDRawTX(frame can.Frame) []byte
- func ParseYDRaw(line string) (can.Frame, bool)
- func ParseYDRawObservation(line string) (raw.Observation, bool)
- func ReadActisense(r io.Reader, handler func(can.Frame)) error
- func ReadActisenseObservations(r io.Reader, handler func(raw.Observation)) error
- func ReadYDRaw(r io.Reader, handler func(can.Frame)) error
- func ReadYDRawObservations(r io.Reader, handler func(raw.Observation)) error
- func Reframe(m N2KMessage, seq uint8) ([]can.Frame, error)
- func ReframeEmitter(handler func(can.Frame)) func(N2KMessage)
- type ActisenseReader
- type ActisenseTCPBus
- func (b *ActisenseTCPBus) Close() error
- func (b *ActisenseTCPBus) Run(ctx context.Context, handler func(can.Frame)) error
- func (b *ActisenseTCPBus) RunObservations(ctx context.Context, handler func(raw.Observation)) error
- func (b *ActisenseTCPBus) SetConnectionObserver(observer func(bool, uint64))
- func (b *ActisenseTCPBus) WriteFrame(frame can.Frame) error
- func (b *ActisenseTCPBus) WriteMessage(pgnNum uint32, priority, _, destination uint8, payload []byte) error
- type Backoff
- type N2KMessage
- type ReconnectPolicy
- type YDRawTCPBus
- func (b *YDRawTCPBus) Close() error
- func (b *YDRawTCPBus) Run(ctx context.Context, handler func(can.Frame)) error
- func (b *YDRawTCPBus) RunObservations(ctx context.Context, handler func(raw.Observation)) error
- func (b *YDRawTCPBus) SetConnectionObserver(observer func(bool, uint64))
- func (b *YDRawTCPBus) WriteFrame(frame can.Frame) error
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func EncodeSend ¶
func EncodeSend(m N2KMessage) ([]byte, error)
EncodeSend renders an assembled N2K message as an Actisense transmit command (0x94). The payload layout is priority (1), PGN (3, little-endian), destination (1), data length (1), data. There is no source-address byte: the gateway transmits under its own claimed bus address, so m.Source is not carried on the wire. The gateway also performs fast-packet fragmentation itself, which is why sends are whole messages rather than CAN frames.
func EncodeStartup ¶
func EncodeStartup() []byte
EncodeStartup renders the gateway initialization command (0xA1 with operating-mode payload 11 02 00) that clears the gateway's transmit filter list so all PGNs flow in both directions. Send it once after connecting; gateways that do not require it ignore it.
func FormatYDRawTX ¶
FormatYDRawTX renders a CAN frame as a Yacht Devices RAW transmit line. Application-to-gateway lines carry no time or direction field — just the 29-bit identifier and the data bytes, CRLF-terminated:
19F51323 01 02<CR><LF>
Once the gateway transmits the frame onto the bus it echoes the line back with a timestamp and direction T, which ParseYDRaw accepts like any other frame. Filtered or malformed lines get no echo.
func ParseYDRaw ¶
ParseYDRaw parses one line of the Yacht Devices RAW protocol (YDWG-02 and compatible gateways), e.g.
17:33:21.107 R 09F11201 01 5C 3D FF 7F FF 7F FC
The direction field is R (received from the bus) or T (transmitted to the bus); both carry frames. Returns ok=false for service messages, blank lines, and anything else that does not carry a CAN data frame.
func ParseYDRawObservation ¶ added in v1.0.0
func ParseYDRawObservation(line string) (raw.Observation, bool)
ParseYDRawObservation preserves the gateway's relative timestamp and receive/transmit direction in addition to the CAN frame.
func ReadActisense ¶ added in v0.2.0
ReadActisense reassembles Actisense messages from r and emits them as re-framed CAN frames until EOF or a read error. It is the single reader for the Actisense protocol, shared by the TCP bus and the read-only network sources.
func ReadActisenseObservations ¶ added in v1.0.0
func ReadActisenseObservations(r io.Reader, handler func(raw.Observation)) error
ReadActisenseObservations preserves the gateway-relative timestamp on every CAN frame reconstructed from an assembled message.
func ReadYDRaw ¶ added in v0.2.0
ReadYDRaw delivers Yacht Devices RAW lines from r as CAN frames until EOF or a read error. It is the single reader for the RAW protocol, shared by the TCP bus and the read-only network sources.
func ReadYDRawObservations ¶ added in v1.0.0
func ReadYDRawObservations(r io.Reader, handler func(raw.Observation)) error
ReadYDRawObservations preserves direction and gateway-relative timestamps.
func Reframe ¶
func Reframe(m N2KMessage, seq uint8) ([]can.Frame, error)
Reframe converts an assembled N2K message back into wire CAN frames: a single frame for non-fast PGNs up to 8 bytes, fast-packet frames for fast PGNs up to 223 bytes. PGNs absent from the metadata tables are framed by size (fast iff the payload exceeds 8 bytes). seq is the fast-packet sequence ID (0-7).
func ReframeEmitter ¶
func ReframeEmitter(handler func(can.Frame)) func(N2KMessage)
ReframeEmitter adapts a CAN-frame handler into an assembled-message consumer: each message is re-framed into wire CAN frames (rotating the fast-packet sequence ID per message) and fed to the handler. Messages that cannot be re-framed are dropped.
Types ¶
type ActisenseReader ¶
type ActisenseReader struct {
// contains filtered or unexported fields
}
ActisenseReader is an incremental decoder for the Actisense binary stream protocol. It tolerates arbitrary buffer boundaries: bytes are fed as they arrive and complete messages are emitted as they are recognized.
func NewActisenseReader ¶
func NewActisenseReader() *ActisenseReader
NewActisenseReader returns a reader ready to consume stream bytes.
func (*ActisenseReader) Feed ¶
func (r *ActisenseReader) Feed(buf []byte, emit func(N2KMessage))
Feed consumes raw stream bytes; emit is called once per complete, checksum-valid N2K message (command 0x93). Garbage between messages is skipped and messages that fail their checksum are dropped silently.
type ActisenseTCPBus ¶
type ActisenseTCPBus struct {
// contains filtered or unexported fields
}
ActisenseTCPBus is a read/write bus over a TCP connection speaking the Actisense binary stream protocol (W2K-1 gateways, or an NGT-1 behind a TCP bridge). The protocol is message-level: incoming messages arrive assembled and are re-framed for the frame-based decode pipeline, and outgoing messages are sent whole via WriteMessage — the gateway performs fast-packet fragmentation and stamps its own claimed source address, so the client's source address is not authoritative on the wire.
func NewActisenseTCPBus ¶
func NewActisenseTCPBus(log *slog.Logger, addr string, reconnect *ReconnectPolicy) *ActisenseTCPBus
NewActisenseTCPBus returns an unconnected bus; Run dials and sends the gateway initialization command. A non-nil reconnect policy makes Run re-dial dropped connections, re-sending the initialization command each time.
func (*ActisenseTCPBus) Close ¶
func (b *ActisenseTCPBus) Close() error
Close releases the connection.
func (*ActisenseTCPBus) Run ¶
Run connects, initializes the gateway, and delivers incoming messages to handler as re-framed CAN frames until ctx is cancelled or (without a reconnect policy) the connection fails.
func (*ActisenseTCPBus) RunObservations ¶ added in v1.0.0
func (b *ActisenseTCPBus) RunObservations(ctx context.Context, handler func(raw.Observation)) error
RunObservations preserves gateway transport context.
func (*ActisenseTCPBus) SetConnectionObserver ¶ added in v1.0.0
func (b *ActisenseTCPBus) SetConnectionObserver(observer func(bool, uint64))
SetConnectionObserver installs reconnect lifecycle observation for Client.
func (*ActisenseTCPBus) WriteFrame ¶
func (b *ActisenseTCPBus) WriteFrame(frame can.Frame) error
WriteFrame transmits one CAN frame as a whole message. This is correct for single-frame PGNs (address claims, ISO requests, transport-protocol frames); fast-packet payloads must go through WriteMessage instead, which the client's write path does automatically.
func (*ActisenseTCPBus) WriteMessage ¶
func (b *ActisenseTCPBus) WriteMessage(pgnNum uint32, priority, _, destination uint8, payload []byte) error
WriteMessage transmits an assembled PGN payload (up to 223 bytes). The source address is accepted for interface symmetry but not transmitted: the gateway substitutes its own claimed address.
type Backoff ¶ added in v0.2.0
type Backoff struct {
// contains filtered or unexported fields
}
Backoff is a re-armable exponential backoff sequencer. It is not safe for concurrent use; a single reconnect loop owns one Backoff.
func NewBackoff ¶ added in v0.2.0
func NewBackoff(policy ReconnectPolicy) *Backoff
NewBackoff returns a Backoff seeded from policy, substituting defaults for any non-positive field.
type N2KMessage ¶
type N2KMessage struct {
Priority uint8
PGN uint32
Destination uint8
Source uint8
Data []byte
// Timestamp is the gateway's relative millisecond clock.
Timestamp time.Duration
HasTimestamp bool
}
N2KMessage is one NMEA 2000 message carried by an Actisense stream. Data is the assembled PGN payload (fast-packet PGNs arrive already assembled).
type ReconnectPolicy ¶ added in v0.2.0
type ReconnectPolicy struct {
// InitialBackoff is the delay before the first reconnect attempt after a
// drop, and the delay restored after any successful connection.
InitialBackoff time.Duration
// MaxBackoff caps the exponentially growing delay between attempts while a
// connection cannot be re-established.
MaxBackoff time.Duration
}
ReconnectPolicy configures automatic re-dialing of a dropped gateway connection. A nil *ReconnectPolicy means reconnection is disabled: a dropped connection ends the read loop (the historical behavior).
type YDRawTCPBus ¶
type YDRawTCPBus struct {
// contains filtered or unexported fields
}
YDRawTCPBus is a read/write bus over a TCP gateway speaking the Yacht Devices RAW line protocol (YDWG-02 RAW server mode and compatibles). RAW mode is frame-level in both directions, so the full client stack — address claiming included — works exactly as it does on CAN hardware. The gateway echoes transmitted frames back with direction T, so the client also observes its own traffic.
func NewYDRawTCPBus ¶
func NewYDRawTCPBus(log *slog.Logger, addr string, reconnect *ReconnectPolicy) *YDRawTCPBus
NewYDRawTCPBus returns an unconnected bus; Run dials. A non-nil reconnect policy makes Run re-dial dropped connections.
func (*YDRawTCPBus) Run ¶
Run connects and delivers incoming frames to handler until ctx is cancelled or (without a reconnect policy) the connection fails.
func (*YDRawTCPBus) RunObservations ¶ added in v1.0.0
func (b *YDRawTCPBus) RunObservations(ctx context.Context, handler func(raw.Observation)) error
RunObservations preserves gateway transport context.
func (*YDRawTCPBus) SetConnectionObserver ¶ added in v1.0.0
func (b *YDRawTCPBus) SetConnectionObserver(observer func(bool, uint64))
SetConnectionObserver installs reconnect lifecycle observation for Client.
func (*YDRawTCPBus) WriteFrame ¶
func (b *YDRawTCPBus) WriteFrame(frame can.Frame) error
WriteFrame transmits one CAN frame as a RAW line.
Source Files