diff options
Diffstat (limited to 'internal/encoding/ssh/filexfer/extended_packets.go')
-rw-r--r-- | internal/encoding/ssh/filexfer/extended_packets.go | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/internal/encoding/ssh/filexfer/extended_packets.go b/internal/encoding/ssh/filexfer/extended_packets.go new file mode 100644 index 0000000..6b7b2ce --- /dev/null +++ b/internal/encoding/ssh/filexfer/extended_packets.go @@ -0,0 +1,142 @@ +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()) +} |