A client to serve a large binary file (typically a disk image) to be transported to multiple listening clients. Allows clients to join at any point.
The client is invoked like this:
multiclient [ -g GROUP ] [ -p PORT ] [ -t TIMEOUT ] [ -f FROM_PORT ] [ -s SERVER_PORT ] [ -f FROM_PORT ] [ -o OUTPUTNAME ]
GROUP is the multicast address, it defaults to 225.0.20.10
PORT is the listen port, it defaults to 16000
TIMEOUT means if the multicast channel goes quiet for this many milliseconds, the client will create and send a block request to the server. Defaults to 1000 or one second.
SERVER_PORT specifies the server's block map port, defaults to 7500
FROM_PORT is a debug option, it sets the source port for the block map to a specific value. It defaults to a random number between 32767 and 65535.
OUTPUTNAME will override the output name supplied by the server. This allows an image file to be directly written to a disk by using -o /dev/sda
Invoke like this:
multiserver -f FILENAME [ -g GROUP ] [ -p PORT ] [ -s SERVER_PORT ] [ -d DELAY ]
GROUP is the multicast address, it defaults to 225.0.20.10
PORT is the listen port, it defaults to 16000
SERVER_PORT specifies the server's block map port, defaults to 7500
DELAY is the interpacket delay for the multicast channel. Don't use this, it makes things horrifically slow, and the block search algorithm means this isn't needed.
Freely available under the terms of the GNU General Public License version 2.
The server starts, prepares a block map for the file to serve, and waits for block requests.
The client starts and sends a map request (once per second) until it receives a block description. It then creates a map of the blocks in the file
The client listens on the multicast channel. If the channel is quiet for a while (default 200 milliseconds) it sends a block request with the first and last empty blocks as endpoints.
The server receives a block request and starts serving blocks in order. Multiple pending requests are coalesced.
The client receives blocks and stores them. The client will create and send a new block request if the line goes quiet.
When all blocks are filled in the client exits.
Could be. Send a bug report, or better yet a patch. Also, the code isn't well commented.
The client filesystem must support sparse files. This is not needed if writing directly to a disk device.
Support creating a file on a filesystem that does not support sparse files.
Support jumbo packets.