2 @unnumbered Chunked files
4 There is ability to transfer huge files with splitting them into smaller
5 chunks. Each chunk is treated like a separate file, producing separate
6 outbound packet unrelated with other ones.
8 This is useful when your removable storage device has smaller capacity
9 than huge file's size. You can transfer those chunks on different
10 storage devices, and/or at different time, reassembling the whole packet
11 on the destination node.
13 Splitting is done with @ref{nncp-file, nncp-file -chunked} command and
14 reassembling with @ref{nncp-reass} command.
16 Chunked @file{FILE} produces @file{FILE.nncp.meta},
17 @file{FILE.nncp.chunk0}, @file{FILE.nncp.chunk1}, ... files. All
18 @file{.nncp.chunkXXX} can be concatenated together to produce original
21 @file{.nncp.meta} contains information about file/chunk
22 size and their hash checksums. This is
23 @url{https://tools.ietf.org/html/rfc4506, XDR}-encoded structure:
26 +------------------------------+---------------------+
27 | MAGIC | FILESIZE | CHUNKSIZE | HASH0 | HASH1 | ... |
28 +------------------------------+---------------------+
31 @multitable @columnfractions 0.2 0.3 0.5
32 @headitem @tab XDR type @tab Value
33 @item Magic number @tab
34 8-byte, fixed length opaque data @tab
35 @verb{|N N C P M 0x00 0x00 0x01|}
37 unsigned hyper integer @tab
38 Whole reassembled file's size
40 unsigned hyper integer @tab
41 Size of each chunk (except for the last one, that could be smaller)
43 variable length array of 32 byte fixed length opaque data @tab
44 BLAKE2b-256 checksum of each chunk