PFSR - Partial file sharing
From DCBase Wiki
Partial File Sharing allows sharing of files which are available in user's download queue or in finished downloads list. As a result of this, new files will be spread much faster over whole network.
When client receives search request (SCH), it looks into shared list to see whether requested hash is available between shared files. If it's found, everything is processed as normally. In other case, it looks into download queue (then, into finished downloads list) and receives a list of available chunks for requested hash. It mustn't take every chunk, but only that ones which are fully downloaded and has already been verified (e.g. against TTH leaves).
The feature should be signalled in SUP as PFSR.
PSR
PSR
Contexts: F, U
States: NORMAL
Information about downloaded and verified chunks is sent to requester with this command. When the requester is active command is sent over UDP (with U type) else it is sent over hub (with D type).
| U4 | UDP IPv4 port or 0 if we don't want receive a response. If UDP port is not zero (it must be when we are passive user), a PSR receiver must respond us with PSR including his available (and verified) chunks. The client must also set UDP port to zero to avoid infinite PSR sending. |
|---|---|
| U6 | Same as U4 but with IPv6 port. |
| TR | File hash |
| PC | Count of downloaded (and verified) chunks the user has. |
| PI | Comma separated list of start and end index of chunks the user has. If a user has a continous block of chunks, the intermittent start and end indexes may be omitted. For example, if a user has chunk 0 and 4 of total 5 chunks, then PI is "0,1,4,5". If the user has chunk 0, 1 and 4, then PI may be "0,1,1,2,4,5" or "0,2,4,5". |
