http://www.linfo.org/bsdlicense.html
The circleme program will brute force crack the pin code on a Circle from Disney https://meetcircle.com/. An extensive blog on hacking the Circle from adding a serial port to disecting the firmeware byte by byte: http://www.hackspot.net/CircleBlog/
sudo dnf install golang
mkdir -p $HOME/gopath
export GOPATH=$HOME/gopath
go get -u github.com/ndragon70/circleme
cd $HOME/gopath/src/github.com/ndragon70/circleme
go build circleme.go
./circleme <ip>