Hi!

This is a collection of custom blocks that are not directly associated with a
special project. For sample applications see:

https://github.com/bastibl/gr-ieee802-11
https://github.com/bastibl/gr-ieee802-15-4



### Wireshark Connector

This blocks outputs PDUs in the PCAP format. The resulting file can be opened in
nearly all network monitoring applications. Some examples are Wireshark, Tshark,
and tcpdump. Currently, it support WiFi packets with radiotap header and ZigBee.

Since GNU Radio does not support File Sinks that append to a file, one can not
open Linux pipes / fifos. For that reason, it is not easily possible to monitor
traffic live. However, loading the file in Wireshark works.

I made a patch that adds an append option to the File Sink. If you are
interested see:
https://github.com/bastibl/gnuradio/commit/befa5bd94b59a56e13d7ec4fe0da86637fe624d9

For further information about radiotap, pcap, and Wireshark see:
http://www.radiotap.org/
http://www.wireshark.org/



### Burst Tagger

Tags a burst / packet with tx_sob und tx_eob tags. This is useful if the SDR is
operating in half duplex mode. With adding a tx_eob the USRP switches back to
receive mode immediately. That way, direct responses like ACKs are not missed.

The block searches for a special tag that indicates the start of a burst. The
name of this tag is configurable. The tag should indicate the length of the
packet in samples. Also a multiplier can be specified, which multiples the
length given in the tag.



### Packet Dropper

Drops a configurable percentage of messages. I used it to test protocol logic
like ACKs, retransmission and stuff.



### Packet Pad

Adds a configurable number of zeros before and after a burst. The burst has to
be started with an tx_sob, and ended with a tx_eob tag.
From time to time I had issues when I did not pad the sample stream. This block
helps to investigate that.
Also it is handy for loopback testing when there is no continues sample stream.



### Periodic Msg Source

This block sends messages at regular intervals  much like the message strobe block in
mainline GNU Radio. With this block you can in addition configure the number of
packets that are sent. When all normal messages are sent, the blocks sends a final
PMT_EOF message to indicate that it is done.

I used this block for performance tests with no-GUI flow graphs. This way it is
possible to shout down no-GUI flow graphs with message blocks. As far as I know,
this is not possible with mainline GNU Radio. For that reason, I created a patch
that checks if the block is done after a message was handled. See

https://github.com/bastibl/gnuradio/commit/75a22cb8c10d867a68c8849bf56a0aa3906df266



### Dependencies

GNU Radio v3.7


### Installation

git clone https://github.com/bastibl/gr-foo.git
cd gr-foo
mkdir build
cd build
cmake ..
make
sudo make install
sudo ldconfig