Skip to content

Latest commit

 

History

History
104 lines (71 loc) · 4.69 KB

doc-ver1.1.md

File metadata and controls

104 lines (71 loc) · 4.69 KB

Doc of NFTP Version1.1

Type of Packet

Type Value (Hex) Description Direction
HELLO 0x01 Always the first packet of Transferring. Sender -> Recver
ACK 0x02 An acknowledge of HELLO packet. Recver -> Sender
FILE 0x03 The FILE packet contains the contents of file. Sender -> Recver
END 0x04 The last packet contain contents of file. Sender -> Recver
GIVEME 0x05 Ask packets with certain IDs. Recver -> Sender

Details of Packets

HELLO Packet

The HELLO packet is the first packet of transferring for one file.

Name Length(Byte) Description
Type 1 HELLO(0x01)
Length 4 The size of this packet.
Packet Id 1 Packet Id. As same as the one in ACK.
Blocks 2 File Blocks number. (Up to 65535)
FileName length 2 The length of file name.
FileName FileName length File name.
File CRC 4 Checksum of content of file.

  • Packet Id is random number generated by sender.

  • Actions

Sender MUST drop it If received a HELLO packet.

After decoding the HELLO packet, something followed should be done.

Create a part file for saving. It should be deleted after finishing receive.

Must return a ACK packet with same PacketID to response.

ACK Packet

The ACK packet is a acknowledge of HELLO packet.

Name Length(Byte) Description
Type 1 ACK(0x02)
Length 4 The size of this packet.
Packet Id 1 Packet id. As same as the one in HELLO.
File Id 4 File Id.
  • Action

Recver MUST drop it If received a ACK packet.

FILE Packet

The FILE packet contains the contents of file. And each block was contained in one Packet. The size of block is define in nftp.h ((256 * 1024) by default).

Name Length(Byte) Description
Type 1 FILE(0x03)
Length 4 The size of this packet.
File Id 4 File Id. As same as the one in ACK.
Block Seq 2 Block sequence number. Start from 0.
Content length 4 The length of content.
Content Content length The content of block.
  • Actions

Sender MUST drop it If received a FILE packet.

Packets from multiple/same files can be transferred at same time.

END Packet

The END Packet is the last packet contain contents of file. It means the ending of transferring for a file.

Name Length(Byte) Description
Type 1 END(0x04)
Length 4 The size of this packet.
File Id 4 File Id. As same as the one in ACK.
Block Seq 2 Block sequence number. Start from 0.
Content length 4 The length of content.
Content Content length The content of block.

GIVEME Packet

The GIVEME packet is use to ask a series of packets with certain IDs from Recver.

Name Length(Byte) Description
Type 1 GIVEME(0x05)
Length 4 The size of this packet.
File Id 4 File Id. As same as the one in ACK.
Blockseq 2 The blockseq of the required packet.

Asking multiple files at once is not supported now :( In the next version of nftp. Ask multiple files will be supported. And the nftp_handler() API may have a change.

Recver MUST drop it If received a GIVEME packet.