87 lines
2.9 KiB
Go
87 lines
2.9 KiB
Go
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package wtwire
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import "io"
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// StateUpdateCode is an error code returned by a watchtower in response to a
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// StateUpdate message.
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type StateUpdateCode = ErrorCode
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const (
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// StateUpdateCodeClientBehind signals that the client's sequence number
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// is behind what the watchtower expects based on its LastApplied. This
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// error should cause the client to record the LastApplied field in the
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// response, and initiate another attempt with the proper sequence
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// number.
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//
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// NOTE: Repeated occurrences of this could be interpreted as an attempt
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// to siphon state updates from the client. If the client believes it
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// is not violating the protocol, this could be grounds to blacklist
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// this tower from future session negotiation.
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StateUpdateCodeClientBehind StateUpdateCode = 70
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// StateUpdateCodeMaxUpdatesExceeded signals that the client tried to
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// send a sequence number beyond the negotiated MaxUpdates of the
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// session.
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StateUpdateCodeMaxUpdatesExceeded StateUpdateCode = 71
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// StateUpdateCodeSeqNumOutOfOrder signals the client sent an update
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// that does not follow the required incremental monotonicity required
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// by the tower.
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StateUpdateCodeSeqNumOutOfOrder StateUpdateCode = 72
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)
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// StateUpdateReply is a message sent from watchtower to client in response to a
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// StateUpdate message, and signals either an acceptance or rejection of the
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// proposed state update.
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type StateUpdateReply struct {
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// Code will be non-zero if the watchtower rejected the state update.
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Code StateUpdateCode
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// LastApplied returns the sequence number of the last accepted update
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// known to the watchtower. If the update was successful, this value
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// should be the sequence number of the last update sent.
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LastApplied uint16
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}
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// A compile time check to ensure StateUpdateReply implements the wtwire.Message
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// interface.
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var _ Message = (*StateUpdateReply)(nil)
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// Decode deserializes a serialized StateUpdateReply message stored in the passed
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// io.Reader observing the specified protocol version.
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//
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// This is part of the wtwire.Message interface.
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func (t *StateUpdateReply) Decode(r io.Reader, pver uint32) error {
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return ReadElements(r,
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&t.Code,
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&t.LastApplied,
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)
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}
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// Encode serializes the target StateUpdateReply into the passed io.Writer
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// observing the protocol version specified.
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//
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// This is part of the wtwire.Message interface.
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func (t *StateUpdateReply) Encode(w io.Writer, pver uint32) error {
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return WriteElements(w,
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t.Code,
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t.LastApplied,
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)
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}
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// MsgType returns the integer uniquely identifying this message type on the
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// wire.
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//
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// This is part of the wtwire.Message interface.
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func (t *StateUpdateReply) MsgType() MessageType {
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return MsgStateUpdateReply
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}
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// MaxPayloadLength returns the maximum allowed payload size for a
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// StateUpdateReply complete message observing the specified protocol version.
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//
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// This is part of the wtwire.Message interface.
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func (t *StateUpdateReply) MaxPayloadLength(uint32) uint32 {
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return 4
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}
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