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message.go
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message.go
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package message
import (
"errors"
"io"
"github.com/francoismichel/ssh3/util"
)
// ssh messages type
const SSH_MSG_DISCONNECT = 1
const SSH_MSG_IGNORE = 2
const SSH_MSG_UNIMPLEMENTED = 3
const SSH_MSG_DEBUG = 4
const SSH_MSG_SERVICE_REQUEST = 5
const SSH_MSG_SERVICE_ACCEPT = 6
const SSH_MSG_KEXINIT = 20
const SSH_MSG_NEWKEYS = 21
const SSH_MSG_USERAUTH_REQUEST = 50
const SSH_MSG_USERAUTH_FAILURE = 51
const SSH_MSG_USERAUTH_SUCCESS = 52
const SSH_MSG_USERAUTH_BANNER = 53
const SSH_MSG_GLOBAL_REQUEST = 80
const SSH_MSG_REQUEST_SUCCESS = 81
const SSH_MSG_REQUEST_FAILURE = 82
const SSH_MSG_CHANNEL_OPEN = 90
const SSH_MSG_CHANNEL_OPEN_CONFIRMATION = 91
const SSH_MSG_CHANNEL_OPEN_FAILURE = 92
const SSH_MSG_CHANNEL_WINDOW_ADJUST = 93
const SSH_MSG_CHANNEL_DATA = 94
const SSH_MSG_CHANNEL_EXTENDED_DATA = 95
const SSH_MSG_CHANNEL_EOF = 96
const SSH_MSG_CHANNEL_CLOSE = 97
const SSH_MSG_CHANNEL_REQUEST = 98
const SSH_MSG_CHANNEL_SUCCESS = 99
const SSH_MSG_CHANNEL_FAILURE = 100
type SSHDataType uint64
const (
SSH_EXTENDED_DATA_NONE SSHDataType = 0
SSH_EXTENDED_DATA_STDERR SSHDataType = 1
)
type Message interface {
Write(buf []byte) (n int, err error)
Length() int
}
type ChannelOpenConfirmationMessage struct {
MaxPacketSize uint64
}
var _ Message = &ChannelOpenConfirmationMessage{}
func ParseChannelOpenConfirmationMessage(buf util.Reader) (*ChannelOpenConfirmationMessage, error) {
maxPacketSize, err := util.ReadVarInt(buf)
if err != nil {
return nil, err
}
return &ChannelOpenConfirmationMessage{
MaxPacketSize: maxPacketSize,
}, nil
}
func (m *ChannelOpenConfirmationMessage) Write(buf []byte) (consumed int, err error) {
varintBuf := util.AppendVarInt(nil, uint64(SSH_MSG_CHANNEL_OPEN_CONFIRMATION))
varintBuf = util.AppendVarInt(varintBuf, m.MaxPacketSize)
consumed = copy(buf, varintBuf)
return consumed, nil
}
func (m *ChannelOpenConfirmationMessage) Length() int {
messageTypeLen := util.VarIntLen(SSH_MSG_CHANNEL_OPEN_CONFIRMATION)
maxPacketSizeLen := util.VarIntLen(m.MaxPacketSize)
return int(messageTypeLen) + int(maxPacketSizeLen)
}
type ChannelOpenFailureMessage struct {
ReasonCode uint64
ErrorMessageUTF8 string
LanguageTag string
}
var _ Message = &ChannelOpenFailureMessage{}
func ParseChannelOpenFailureMessage(buf util.Reader) (*ChannelOpenFailureMessage, error) {
reasonCode, err := util.ReadVarInt(buf)
if err != nil {
return nil, err
}
errorMessageUTF8, err := util.ParseSSHString(buf)
if err != nil {
return nil, err
}
languageTag, err := util.ParseSSHString(buf)
if err != nil {
return nil, err
}
return &ChannelOpenFailureMessage{
ReasonCode: reasonCode,
ErrorMessageUTF8: errorMessageUTF8,
LanguageTag: languageTag,
}, nil
}
func (m *ChannelOpenFailureMessage) Length() int {
messageTypeLen := util.VarIntLen(SSH_MSG_CHANNEL_OPEN_FAILURE)
reasonCodeLen := util.VarIntLen(m.ReasonCode)
return int(messageTypeLen) + int(reasonCodeLen) + util.SSHStringLen(m.ErrorMessageUTF8) + util.SSHStringLen(m.LanguageTag)
}
func (m *ChannelOpenFailureMessage) Write(buf []byte) (consumed int, err error) {
if len(buf) < m.Length() {
return 0, errors.New("buffer too small to write channel open failure message")
}
varintBuf := util.AppendVarInt(nil, uint64(SSH_MSG_CHANNEL_OPEN_FAILURE))
varintBuf = util.AppendVarInt(varintBuf, uint64(m.ReasonCode))
consumed += copy(buf[consumed:], varintBuf)
n, err := util.WriteSSHString(buf[consumed:], m.ErrorMessageUTF8)
if err != nil {
return 0, err
}
consumed += n
n, err = util.WriteSSHString(buf[consumed:], m.LanguageTag)
if err != nil {
return 0, err
}
consumed += n
return consumed, nil
}
type DataOrExtendedDataMessage struct {
DataType SSHDataType
Data string
}
var _ Message = &DataOrExtendedDataMessage{}
func ParseDataMessage(buf util.Reader) (*DataOrExtendedDataMessage, error) {
data, err := util.ParseSSHString(buf)
if err != nil && err != io.EOF {
return nil, err
}
return &DataOrExtendedDataMessage{
DataType: SSH_EXTENDED_DATA_NONE,
Data: data,
}, nil
}
func (m *DataOrExtendedDataMessage) Write(buf []byte) (consumed int, err error) {
if m.DataType == SSH_EXTENDED_DATA_NONE {
msgTypeBuf := util.AppendVarInt(nil, uint64(SSH_MSG_CHANNEL_DATA))
consumed += copy(buf[consumed:], msgTypeBuf)
} else {
msgTypeBuf := util.AppendVarInt(nil, uint64(SSH_MSG_CHANNEL_EXTENDED_DATA))
consumed += copy(buf[consumed:], msgTypeBuf)
dataTypeBuf := util.AppendVarInt(nil, uint64(m.DataType))
consumed += copy(buf[consumed:], dataTypeBuf)
}
n, err := util.WriteSSHString(buf[consumed:], m.Data)
if err != nil {
return 0, err
}
consumed += n
return consumed, nil
}
func (m *DataOrExtendedDataMessage) Length() int {
if m.DataType == SSH_EXTENDED_DATA_NONE {
messageTypeLen := util.VarIntLen(SSH_MSG_CHANNEL_DATA)
return int(messageTypeLen) + int(util.SSHStringLen(m.Data))
}
messageTypeLen := util.VarIntLen(SSH_MSG_CHANNEL_EXTENDED_DATA)
return int(messageTypeLen) + int(util.VarIntLen(uint64(m.DataType))) + int(util.SSHStringLen(m.Data))
}
func ParseExtendedDataMessage(buf util.Reader) (*DataOrExtendedDataMessage, error) {
dataType, err := util.ReadVarInt(buf)
if err != nil {
return nil, err
}
data, err := util.ParseSSHString(buf)
if err != nil && err != io.EOF {
return nil, err
}
return &DataOrExtendedDataMessage{
DataType: SSHDataType(dataType),
Data: data,
}, err
}
func ParseMessage(r util.Reader) (Message, error) {
typeId, err := util.ReadVarInt(r)
if err != nil {
return nil, err
}
switch typeId {
case SSH_MSG_CHANNEL_REQUEST:
return ParseRequestMessage(r)
case SSH_MSG_CHANNEL_OPEN_CONFIRMATION:
return ParseChannelOpenConfirmationMessage(r)
case SSH_MSG_CHANNEL_OPEN_FAILURE:
return ParseChannelOpenFailureMessage(r)
case SSH_MSG_CHANNEL_DATA, SSH_MSG_CHANNEL_EXTENDED_DATA:
if typeId == SSH_MSG_CHANNEL_DATA {
return ParseDataMessage(r)
} else {
return ParseExtendedDataMessage(r)
}
default:
panic("not implemented")
}
}