dvg-gse is a Rust implementation of the DVB GSE (Generic Stream Encapsulation) protocol, GSE-HEM, and related protocols.
It is mainly intended to be used as a CLI application that receives BBFRAMEs in UDP or TCP packets from a DVB-S2 receiver (such as Longmynd or commercial receivers supporting BBFRAME output), obtains IP packets from a continous-mode GSE stream or a GSE-HEM stream, and sends the IP packets to a TUN device.
The crate can also be used as a library to process GSE Packets and DVB-S2/DVB-S2X BBFRAMES.
Install dvb-gse with cargo:
cargo install dvb-gse
Create a TUN device to receive the IP packets:
sudo ip tuntap add dev tun0 mode tun
sudo ip link set tun0 up
Run dvb-gse:
dvb-gse --listen 0.0.0.0:2000 --tun tun0
It is possible to use the environment variable RUST_LOG=debug or
RUST_LOG=trace to see more detailed logging information.
Now send BBFRAMEs to UDP port 2000 (how to do this will depend on the DVB-S2
receiver being used). dvb-gse will obtain the IP packets from the GSE stream
and write them into the tun0 interface. These packets can be inspected by
running Wireshark or tcpdump in tun0.
The CLI application supports the following input formats for the BBFRAMEs. The
input format is selected with the --input argument:
This corresponds to BBFRAMEs fragmented into multiple UDP packets (since usually DVB-S2 BBFRAMEs are larger than a 1500 byte MTU). The following rules need to be followed.
-
The payload of each UDP packet can optionally begin by a header of up to 64 bytes, which is discarded by this application. The header length is set with the
--header-lengthargument. By default, no header is assumed. -
The beginning of each BBFRAME should happen at the end of a header, or at the beginning of the payload of a UDP packet if there is no header.
-
The BBFRAME padding can either be removed or be present. If possible, it is recommended to remove the BBFRAME padding, in order to reduce the network traffic and to simplify the operation of the defragmenter.
-
BBFRAMEs can be fragmented into multiple UDP packets in any way.
The CLI application tries to recover from dropped UDP packets.
This corresponds to BBFRAMEs carried in a single UDP packet (it will typically be a jumbo packet). The following rules need to be followed.
-
The payload of each UDP packet can optionally be begin by a header of up to 64 bytes, which is discarded by this application. The header length is set with the
--header-lengthargument. By default, no header is assumed. -
Each BBFRAME should be completely contained in a single UDP packet. The BBFRAME should follow the header immediately.
-
There can be padding or any other data following the BBFRAME in the same UDP packet.
UDP packets can be dropped. The CLI application will handle this gracefully.
This corresponds to receiving BBFRAMEs in a TCP stream. The CLI application acts as server. The following rules need to be followed.
-
Each BBFRAME can optionally be preceded by a header of up to 64 bytes, which is discarded by this application. The header length is set with the
--header-lengthargument. By default, no header is assumed. -
BBFRAMEs (including their headers, if applicable) need to be present back to back in the TCP stream.
-
BBFRAMEs padding must be removed. The length of the BBFRAMEs in the stream must equal 10 bytes for the BBHEADER plus the value of their DFL dividided by 8.
-
No other data besides the headers and BBFRAMEs can be present in the TCP stream.
If an error occurrs or the client closes the connection, the CLI application will continue to listen for new clients.
GSE-HEM is auto-detected by using the TS/GS field in the BBHEADER (both continuous GSE and GSE-HEM are supported).
A test script that generates UDP packets containing GSE-HEM BBFRAMEs is included
in
utils/generate_test_gse_hem_bbframes.py. This
test script can be used by first running dvb-gse as indicated in the
quickstart above (possibly by using RUST_LOG=trace), and then starting the
generate_test_gse_hem_bbframes.py script. IPv6 UDP packets should be received
in tun0 and dvb-gse should log information about the received packets if the
logging level is debug or trace.
The documentation for dvb-gse Rust crate is hosted in docs.rs.
Licensed under either of
- Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.