diff options
Diffstat (limited to 'internal/encoding/ssh/filexfer/filexfer.go')
| -rw-r--r-- | internal/encoding/ssh/filexfer/filexfer.go | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/internal/encoding/ssh/filexfer/filexfer.go b/internal/encoding/ssh/filexfer/filexfer.go new file mode 100644 index 0000000..1e5abf7 --- /dev/null +++ b/internal/encoding/ssh/filexfer/filexfer.go @@ -0,0 +1,54 @@ +// Package filexfer implements the wire encoding for secsh-filexfer as described in https://tools.ietf.org/html/draft-ietf-secsh-filexfer-02 +package filexfer + +// PacketMarshaller narrowly defines packets that will only be transmitted. +// +// ExtendedPacket types will often only implement this interface, +// since decoding the whole packet body of an ExtendedPacket can only be done dependent on the ExtendedRequest field. +type PacketMarshaller interface { + // MarshalPacket is the primary intended way to encode a packet. + // The request-id for the packet is set from reqid. + // + // An optional buffer may be given in b. + // If the buffer has a minimum capacity, it shall be truncated and used to marshal the header into. + // The minimum capacity for the packet must be a constant expression, and should be at least 9. + // + // It shall return the main body of the encoded packet in header, + // and may optionally return an additional payload to be written immediately after the header. + // + // It shall encode in the first 4-bytes of the header the proper length of the rest of the header+payload. + MarshalPacket(reqid uint32, b []byte) (header, payload []byte, err error) +} + +// Packet defines the behavior of a full generic SFTP packet. +// +// InitPacket, and VersionPacket are not generic SFTP packets, and instead implement (Un)MarshalBinary. +// +// ExtendedPacket types should not iplement this interface, +// since decoding the whole packet body of an ExtendedPacket can only be done dependent on the ExtendedRequest field. +type Packet interface { + PacketMarshaller + + // Type returns the SSH_FXP_xy value associated with the specific packet. + Type() PacketType + + // UnmarshalPacketBody decodes a packet body from the given Buffer. + // It is assumed that the common header values of the length, type and request-id have already been consumed. + // + // Implementations should not alias the given Buffer, + // instead they can consider prepopulating an internal buffer as a hint, + // and copying into that buffer if it has sufficient length. + UnmarshalPacketBody(buf *Buffer) error +} + +// ComposePacket converts returns from MarshalPacket into an equivalent call to MarshalBinary. +func ComposePacket(header, payload []byte, err error) ([]byte, error) { + return append(header, payload...), err +} + +// Default length values, +// Defined in draft-ietf-secsh-filexfer-02 section 3. +const ( + DefaultMaxPacketLength = 34000 + DefaultMaxDataLength = 32768 +) |