D-LAN

h1. Protocols

* [[Protocol core-core]]

* [[Protocol core-GUI]]

There is two main protocols, one between cores and one between GUI and core. Both are using "protocol buffers":http://code.google.com/p/protobuf/ for describing the exchanged messages.

Each data sent over the network (using TCP or UDP) are formatted like this :

<pre>

<messageType:uint32><size:uint32><senderId:20*uint8><serializedMessage>

</pre>

Where :

* _messageType_ is a number which determine the message type, more information in the proto files.

* _size_ is the size of the following serialized message. It may be zero for an empty message.

* _senderId_ is the sender id.

* _serializedMessage_ is the data serialized by protocol buffer.

The first three items is the header and is exactly 28 bytes long.

h2. Links to resource (DRAFT)

h3. Proposal 1

Links can be shared across peers. It locates a remote resource like folder or file from a specific peer. It can contain chunk hashes, thus the source peer doesn't need to be online to download a file or a folder.

_dl://[<peer name>][:<file id>][:<shared id>/<folder>/<file>]_

* <peer name> : Not required and not used to locate the resource, just an information for the user.

* <file id> : its the n first group of nibble of the m first chunk where _n * m = 40 nibbles_ (20 octets).

** 20,87cace382f7371cd3fab3cb0a53b93b7cd9719f6 : 20 chunks of 2 nibbles.

** 8,05649bcbf065e0d032ada540d4a749d98db055cf : 8 chunks of 5 nibbles.

* <shared id> : Contains only the beginning of the hash.

h4. Examples

* _dl://20,87cace382f7371cd3fab3cb0a53b93b7cd9719f6_

* _dl://pierre:20,87cace382f7371cd3fab3cb0a53b93b7cd9719f6_

* _dl://pierre:20,87cace382f7371cd3fab3cb0a53b93b7cd9719f6:dac4f75c/my%20movies/LOLCat.avi_

* _dl://pierre:dac4f75c/my%20movies/LOLCat.avi_

* _dl://pierre:dac4f75c/my%20movies_

h3. Proposal 2

This version is much simpler, it doesn't identify the file and contains only the path to the ressource.

_dl://<peer name>(<peer ID>)<path>_

_<path>_ always starts with a slash. It can be a folder or a file.

h4. Examples

* _dl://pierre(d51f479)/my%20movies/LOLCat.avi_

h3. Proposal 3

Folders: _dl://[<peer name>]:[<peer id>]:(<shared id>|<shared name>)[/<path>]_

Files: _dl://<file id>:<file name>

<file id> is a hash built from all the chunk hashes. A new field must be added to the IMAlive message to ask if someone know a particular file ID, is someone know the file ID then he replies with a ChunksOwned message (rename the message?) with a field named file_state.

h4. Examples

* _dl://Pierre::a%20shared%20folder/my%20movies/_

* _dl://Pierre:7c0215d7f758bce8d00ffc467be7d5f5f7c9f929:a%20shared%20folder/my%20movies/_

* _dl://Pierre:7c0215d7f758bce8d00ffc467be7d5f5f7c9f929:68181cd1c7495122493b74170f76700ac30c81d1/my%20movies/_

* _dl://ea627f2d65c12a78aa5c0c154ba7e187d3fefe80:my%20movies/LOLCat.avi