common.go

// Copyright (C) 2019, 2021 Yawning Angel. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
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// 1. Redistributions of source code must retain the above copyright
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// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
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// this software without specific prior written permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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// Package nyquist implements the Noise Protocol Framework.
package nyquist // import "gitlab.com/yawning/nyquist.git"

import "errors"

// Version is the revision of the Noise specification implemented.
const Version = 34

var (
	// ErrNonceExhausted is the error returned when the CipherState's
	// nonce space is exhausted.
	ErrNonceExhausted = errors.New("nyquist: nonce exhausted")

	// ErrMessageSize is the error returned when an operation fails due
	// to the message size being exceeded.
	ErrMessageSize = errors.New("nyquist: oversized message")

	// ErrOpen is the error returned on a authenticated decryption failure.
	ErrOpen = errors.New("nyquist: decryption failure")

	// ErrInvalidConfig is the error returned when the configuration is invalid.
	ErrInvalidConfig = errors.New("nyquist: invalid configuration")

	// ErrOutOfOrder is the error returned when ReadMessage/WriteMessage
	// are called out of order, given the handshake's initiator status.
	ErrOutOfOrder = errors.New("nyquist: out of order handshake operation")

	// ErrDone is the error returned when the handshake is complete.
	ErrDone = errors.New("nyquist: handshake complete")

	// ErrProtocolNotSupported is the error returned when a requested protocol
	// is not supported.
	ErrProtocolNotSupported = errors.New("nyquist: protocol not supported")
)

func truncateTo32BytesMax(b []byte) []byte {
	if len(b) <= 32 {
		return b
	}

	return b[:32]
}