package filexfer
import (
"encoding"
"sync"
)
// ExtendedData aliases the untyped interface composition of encoding.BinaryMarshaler and encoding.BinaryUnmarshaler.
type ExtendedData = interface {
encoding.BinaryMarshaler
encoding.BinaryUnmarshaler
}
// ExtendedDataConstructor defines a function that returns a new(ArbitraryExtendedPacket).
type ExtendedDataConstructor func() ExtendedData
var extendedPacketTypes = struct {
mu sync.RWMutex
constructors map[string]ExtendedDataConstructor
}{
constructors: make(map[string]ExtendedDataConstructor),
}
// RegisterExtendedPacketType defines a specific ExtendedDataConstructor for the given extension string.
func RegisterExtendedPacketType(extension string, constructor ExtendedDataConstructor) {
extendedPacketTypes.mu.Lock()
defer extendedPacketTypes.mu.Unlock()
if _, exist := extendedPacketTypes.constructors[extension]; exist {
panic("encoding/ssh/filexfer: multiple registration of extended packet type " + extension)
}
extendedPacketTypes.constructors[extension] = constructor
}
func newExtendedPacket(extension string) ExtendedData {
extendedPacketTypes.mu.RLock()
defer extendedPacketTypes.mu.RUnlock()
if f := extendedPacketTypes.constructors[extension]; f != nil {
return f()
}
return new(Buffer)
}
// ExtendedPacket defines the SSH_FXP_CLOSE packet.
type ExtendedPacket struct {
ExtendedRequest string
Data ExtendedData
}
// Type returns the SSH_FXP_xy value associated with this packet type.
func (p *ExtendedPacket) Type() PacketType {
return PacketTypeExtended
}
// MarshalPacket returns p as a two-part binary encoding of p.
//
// The Data is marshaled into binary, and returned as the payload.
func (p *ExtendedPacket) MarshalPacket(reqid uint32, b []byte) (header, payload []byte, err error) {
buf := NewBuffer(b)
if buf.Cap() < 9 {
size := 4 + len(p.ExtendedRequest) // string(extended-request)
buf = NewMarshalBuffer(size)
}
buf.StartPacket(PacketTypeExtended, reqid)
buf.AppendString(p.ExtendedRequest)
if p.Data != nil {
payload, err = p.Data.MarshalBinary()
if err != nil {
return nil, nil, err
}
}
return buf.Packet(payload)
}
// UnmarshalPacketBody unmarshals the packet body from the given Buffer.
// It is assumed that the uint32(request-id) has already been consumed.
//
// If p.Data is nil, and the extension has been registered, a new type will be made from the registration.
// If the extension has not been registered, then a new Buffer will be allocated.
// Then the request-specific-data will be unmarshaled from the rest of the buffer.
func (p *ExtendedPacket) UnmarshalPacketBody(buf *Buffer) (err error) {
if p.ExtendedRequest, err = buf.ConsumeString(); err != nil {
return err
}
if p.Data == nil {
p.Data = newExtendedPacket(p.ExtendedRequest)
}
return p.Data.UnmarshalBinary(buf.Bytes())
}
// ExtendedReplyPacket defines the SSH_FXP_CLOSE packet.
type ExtendedReplyPacket struct {
Data ExtendedData
}
// Type returns the SSH_FXP_xy value associated with this packet type.
func (p *ExtendedReplyPacket) Type() PacketType {
return PacketTypeExtendedReply
}
// MarshalPacket returns p as a two-part binary encoding of p.
//
// The Data is marshaled into binary, and returned as the payload.
func (p *ExtendedReplyPacket) MarshalPacket(reqid uint32, b []byte) (header, payload []byte, err error) {
buf := NewBuffer(b)
if buf.Cap() < 9 {
buf = NewMarshalBuffer(0)
}
buf.StartPacket(PacketTypeExtendedReply, reqid)
if p.Data != nil {
payload, err = p.Data.MarshalBinary()
if err != nil {
return nil, nil, err
}
}
return buf.Packet(payload)
}
// UnmarshalPacketBody unmarshals the packet body from the given Buffer.
// It is assumed that the uint32(request-id) has already been consumed.
//
// If p.Data is nil, and there is request-specific-data,
// then the request-specific-data will be wrapped in a Buffer and assigned to p.Data.
func (p *ExtendedReplyPacket) UnmarshalPacketBody(buf *Buffer) (err error) {
if p.Data == nil {
p.Data = new(Buffer)
}
return p.Data.UnmarshalBinary(buf.Bytes())
}
