// consts.go - consts for hkexnet

// Copyright (c) 2017-2018 Russell Magee
// Licensed under the terms of the MIT license (see LICENSE.mit in this
// distribution)
//
// golang implementation by Russ Magee (rmagee_at_gmail.com)
package hkexnet

const (
	KEX_HERRADURA256 = iota // this MUST be first for default if omitted in ctor
	KEX_HERRADURA512
	KEX_HERRADURA1024
	KEX_HERRADURA2048
	KEX_resvd4
	KEX_resvd5
	KEX_resvd6
	KEX_resvd7
	KEX_KYBER512
	KEX_KYBER768
	KEX_KYBER1024
	KEX_resvd11
	KEX_resvd12
	KEX_resvd13
	KEX_resvd14
	KEX_resvd15
)

// Sent from client to server in order to specify which
// algo shall be used (eg., HerraduraKEx, [TODO: others...])
type KEXAlg uint8

const (
	CSENone        = 32 + iota
	CSEBadAuth     // Failed login password
	CSETruncCSO    // No CSOExitStatus in payload
	CSEStillOpen   // Channel closed unexpectedly
	CSEExecFail    // cmd.Start() (exec) failed
	CSEPtyExecFail // pty.Start() (exec w/pty) failed
)

// Extended (>255 UNIX exit status) codes
// This indicate channel-related or internal errors
type CSExtendedCode uint32

const (
	CSONone        = iota // No error, normal packet
	CSOHmacInvalid        // HMAC mismatch detected on remote end
	CSOTermSize           // set term size (rows:cols)
	CSOExitStatus         // Remote cmd exit status
	CSOChaff              // Dummy packet, do not pass beyond decryption
)

// Channel status type
type CSOType uint32

//TODO: this should be small (max unfragmented packet size?)
const MAX_PAYLOAD_LEN = 4*1024*1024*1024 - 1

const (
	CAlgAES256     = iota
	CAlgTwofish128 // golang.org/x/crypto/twofish
	CAlgBlowfish64 // golang.org/x/crypto/blowfish
	CAlgCryptMT1   //cryptmt using mtwist64
	CAlgNoneDisallowed
)

// Available ciphers for hkex.Conn
type CSCipherAlg uint32

const (
	HmacSHA256 = iota
	HmacSHA512
	HmacNoneDisallowed
)

// Available HMACs for hkex.Conn (TODO: not currently used)
type CSHmacAlg uint32