# author: andre boyce
# license: GPLV2
# version: 1

# copy paste ready
# Enable Google’s TCP BBR on a Linux VPS
# creates 2 files enable_google_tcp_bbr disable_google_tcp_bbr
# todo maybe add quiet option
# maybe make sed commands fit on one line

# make a directory called scripts in the home directory
mkdir -p ~/scripts
# move in to the scripts directory
cd ~/scripts
# create a file called enable_google_tcp_bbr
touch enable_google_tcp_bbr
# make the file executable
chmod +x enable_google_tcp_bbr

# echo this script in to the file
echo '
# Enable Google’s TCP BBR on a Linux VPS
# tested on ununtu 20.04, centos 8
# run as root or as user with sudo

# get the major_version of the kernel by splitting the result of uname -r by "." first column. e.g. 2.4.0 should give 2
major_version=$(uname -r | awk -F"." '\''{print $1}'\'')

# get the minor_version of the kernel by splitting the result of uname -r by "." second column.  e.g. 2.4.0 should give 4
minor_version=$(uname -r | awk -F"." '\''{print $2}'\'')

# if major_version of kernel less than 4.x.x
if [ "$major_version" -lt "4" ]
then
   echo "Kernel version is: $major_version.$minor_version which is too low please upgrade kernel to version 4.9.0 or greater"
   echo -e "\033[0;31mFailed\033[m" && exit 1;
else
   # if major_version of kernel is equal to 4.x.x then check if minor version less than 6
   if [ "$major_version" -eq "4" ] && [ $minor_version -lt "9" ]
   then
      echo "Kernel version is: $major_version.$minor_version which is too low please upgrade kernel to version 4.9.0 or greater"
      echo -e "\033[0;31mFailed\033[m" && exit 1;
   else
      echo "Kernel version is: $major_version.$minor_version which is ok"
   fi
fi

# backup /etc/sysctl.conf
yes | sudo cp /etc/sysctl.conf /etc/sysctl.conf.bak

# if we find "net.core.default_qdisc=fq" in /etc/sysctl.conf
if sudo grep -Fq "net.core.default_qdisc=fq" /etc/sysctl.conf
then
   # echo "net.core.default_qdisc=fq present in /etc/sysctl.conf"
   :
else
   echo "net.core.default_qdisc=fq" | sudo tee -a /etc/sysctl.conf
fi

# if we find "net.ipv4.tcp_congestion_control=bbr" in /etc/sysctl.conf
if sudo grep -Fq "net.ipv4.tcp_congestion_control=bbr" /etc/sysctl.conf
then
   # echo "net.ipv4.tcp_congestion_control=bbr present in /etc/sysctl.conf"
   :
else
   echo "net.ipv4.tcp_congestion_control=bbr" | sudo tee -a /etc/sysctl.conf
fi

# show differences
# sudo diff /etc/sysctl.conf /etc/sysctl.conf.bak

# Reload configuration
sudo sysctl -qp

# if it worked then expected output net.ipv4.tcp_congestion_control = bbr
if sudo sysctl net.ipv4.tcp_congestion_control | grep -q "net.ipv4.tcp_congestion_control = bbr" ; then echo -e "\033[0;32mSuccess\033[m" && exit 0; else echo -e "\033[0;31mFailed\033[m" && exit 1; fi

' > ~/scripts/enable_google_tcp_bbr

# execute the script we created
./enable_google_tcp_bbr

# create another file to disable google_tcp_bbr
touch disable_google_tcp_bbr
chmod +x disable_google_tcp_bbr

cat > ~/scripts/disable_google_tcp_bbr << EOF
# remove net.core.default_qdisc=fq from /etc/sysctl.conf
# remove net.ipv4.tcp_congestion_control=bbr from /etc/sysctl.conf

# if we find "net.core.default_qdisc=fq" in /etc/sysctl.conf
if sudo grep -Fq "net.core.default_qdisc=fq" /etc/sysctl.conf
then
   # note would be nice to get sed to do this in one line
   # remove net.ipv4.tcp_congestion_control=bbr from /etc/sysctl.conf
   sudo sed -i "s/^net\.core\.default_qdisc\=fq//" /etc/sysctl.conf
   # remove trailing empty lines
   sudo sed -Ezi '$ s/\n+$//' /etc/sysctl.conf
   echo -e "" | sudo tee -a /etc/sysctl.conf
   echo "net.core.default_qdisc=fq removed from /etc/sysctl.conf"
else
   echo "net.core.default_qdisc=fq not found in /etc/sysctl.conf"
fi
# if we find "net.ipv4.tcp_congestion_control=bbr" in /etc/sysctl.conf
if sudo grep -Fq "net.ipv4.tcp_congestion_control=bbr" /etc/sysctl.conf
then
   # note would be nice to get sed to do this in one line
   # remove net.ipv4.tcp_congestion_control=bbr from /etc/sysctl.conf
   sudo sed -i "s/^net\.ipv4\.tcp_congestion_control\=bbr//" /etc/sysctl.conf
   # remove trailing empty lines
   sudo sed -Ezi '$ s/\n+$//' /etc/sysctl.conf
   echo -e "" | sudo tee -a /etc/sysctl.conf
   echo "net.ipv4.tcp_congestion_control=bbr removed from /etc/sysctl.conf"
else
   echo "net.ipv4.tcp_congestion_control=bbr not found in /etc/sysctl.conf"
fi

# Reload configuration
sudo sysctl -qp

if ! sudo grep -Fq "net.core.default_qdisc=fq" /etc/sysctl.conf && ! sudo grep -Fq "net.ipv4.tcp_congestion_control=bbr" /etc/sysctl.conf ; then echo -e "\033[0;32mSuccess\033[m" ; exit 0; else echo -e "\033[0;31mFailed\033[m" ; exit 1; fi
EOF

ls