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Add LZ4 compression

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This commit is contained in:
Jakob Borg
2014-07-25 15:16:23 +02:00
parent e8c8cc550b
commit fbf8f3dc68
18 changed files with 14005 additions and 26 deletions
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35
protocol/PROTOCOL.md
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@@ -25,11 +25,13 @@ Transport and Authentication
----------------------------
BEP is deployed as the highest level in a protocol stack, with the lower
level protocols providing encryption and authentication.
level protocols providing compression, encryption and authentication.
+-----------------------------|
| Block Exchange Protocol |
|-----------------------------|
| Compression (LZ4) |
|-----------------------------|
| Encryption & Auth (TLS 1.2) |
|-----------------------------|
| TCP |
@@ -60,6 +62,37 @@ requests are received.
The underlying transport protocol MUST be TCP.
Compression
-----------
All data is sent within compressed blocks. Blocks are compressed using
the LZ4 format and algorithm described in
https://code.google.com/p/lz4/. Each compressed block is preceded by a
header consisting of three 32 bit words, in network order (big endian):
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Magic (0x0x5e63b278) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Uncompressed Block Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ /
\ Compressed Data \
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Data Length indicates the length of data following the Data Length
field until the next header, i.e. the length of the Compressed Data
section plus four bytes for the Uncompressed Block Length field. The
Uncompressed Block Length indicates the amount of data that will result
when decompressing the Compressed Data section.
A single BEP message SHOULD be sent as a single compressed block. A
single compressed block MAY NOT contain more than one BEP message.
Messages
--------