#!/bin/bash

# 10/04/2024
## Checklist ##
# - Install useful tools
# - Disable UFW (with Ubuntu) or Firewalld (CentOS)
# - Disable SELinux
# - Permit root login via SSH
# - Grant execution permission for the rc.local script
# - Disable Pstate
# - Fix CentOS 6 repo

os=$(grep "^ID=" /etc/os-release | cut -d '=' -f2 | tr -d '"')
version=$(grep "VERSION_ID=" /etc/os-release | cut -d '=' -f2 | tr -d '"')
publicIP=$(curl ipinfo.io/ip)
cpuInfo=$(lscpu | egrep 'Model name|Socket|^CPU\(s\)' | tr -s " ")
memoryInfo=$(free -mh | grep Mem | awk '{print $2}' | tr -s " ")
diskInfo=$(df -h / --output=size | tail -1 | tr -s " ")
centPackage=("tcpdump" "telnet" "net-tools" "vim" "screen" "bind-utils" "epel-release" "jq" "smartmontools")
ubtPackage=("tcpdump" "telnet" "vim" "iptables-persistent" "jq" "smartmontools")

echo "=== Server Info Summary ==="
echo -e "$cpuInfo \nRam: $memoryInfo \nRoot: $diskInfo \nOS: $os - $version"
sleep 5
clear
sleep 1

# Permit root login via SSH
sed -i.bak '/PermitRootLogin/d' /etc/ssh/sshd_config
echo "PermitRootLogin yes" >> /etc/ssh/sshd_config

# Add additional SSH configuration
echo "=== Add additional SSH configuration ==="
grep -qxF '# KeepAlive Options' /etc/ssh/sshd_config || echo -e "\n# KeepAlive Options" >> /etc/ssh/sshd_config
grep -qxF 'UseDNS no' /etc/ssh/sshd_config || echo "UseDNS no" >> /etc/ssh/sshd_config
grep -qxF 'ClientAliveInterval 0' /etc/ssh/sshd_config || echo "ClientAliveInterval 0" >> /etc/ssh/sshd_config
grep -qxF 'ClientAliveCountMax 0' /etc/ssh/sshd_config || echo "ClientAliveCountMax 0" >> /etc/ssh/sshd_config
grep -qxF 'GSSAPIAuthentication no' /etc/ssh/sshd_config || echo "GSSAPIAuthentication no" >> /etc/ssh/sshd_config

# Restart SSH service to apply new configurations
if systemctl is-active --quiet sshd; then
    echo "Restarting sshd..."
    systemctl restart sshd
elif systemctl is-active --quiet ssh; then
    echo "Restarting ssh..."
    systemctl restart ssh
else
    echo "Neither sshd nor ssh is active."
fi

pstate=$(grep "intel_pstate=disable" /etc/default/grub)
if [[ $pstate == "" ]]; then
  echo 'GRUB_CMDLINE_LINUX_DEFAULT="intel_pstate=disable"' >> /etc/default/grub
fi

case $os in
"ubuntu")
  ufw disable &> /dev/null
  apt update -y
  apt install psmisc -y
  apt install htop -y
  apt upgrade -y
  systemctl stop chronyd
  systemctl disable chronyd
  grub-mkconfig -o /boot/grub/grub.cfg

  for i in "${ubtPackage[@]}"; do apt install $i -y; done
  ;;

"centos")
  if [[ $version == "6" ]]; then
    mv /etc/yum.repos.d/CentOS* /root/
    touch /etc/yum.repos.d/CISP.repo

cat <<EOF > /etc/yum.repos.d/CISP.repo
[CISP]
name=CISP Repository
baseurl=http://mirror.cisp.com/CentOS/6/os/x86_64/
enabled=1
gpgcheck=1
gpgkey=http://mirror.cisp.com/CentOS/6/os/x86_64/RPM-GPG-KEY-CentOS-6
EOF
  elif [[ $version == "7" ]]; then
    # Xử lý cho CentOS 7
    mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak

cat <<EOF > /etc/yum.repos.d/CentOS-Base.repo
[base]
name=CentOS-\$releasever - Base
baseurl=https://mirror.vietnix.vn/centos-vault/7.9.2009/os/\$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

[updates]
name=CentOS-\$releasever - Updates
baseurl=https://mirror.vietnix.vn/centos-vault/7.9.2009/updates/\$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

[extras]
name=CentOS-\$releasever - Extras
baseurl=https://mirror.vietnix.vn/centos-vault/7.9.2009/extras/\$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

[centosplus]
name=CentOS-\$releasever - Plus
baseurl=https://mirror.vietnix.vn/centos-vault/7.9.2009/centosplus/\$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF

# Vô hiệu hóa SELinux
    sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config
    setenforce 0

# Dừng và vô hiệu hóa các dịch vụ không cần thiết
    systemctl stop firewalld
    systemctl disable firewalld
    systemctl mask firewalld

    systemctl stop chronyd
    systemctl disable chronyd

# Cập nhật hệ thống và cài đặt các gói cần thiết
    yum update -y
    yum install -y psmisc htop wget net-tools vim

# Tạo file cấu hình GRUB mới
    [ -d /sys/firmware/efi ] && grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg || grub2-mkconfig -o /boot/grub2/grub.cfg

# Cấp quyền thực thi cho rc.local
    chmod +x /etc/rc.local

# Cài đặt các gói từ mảng `centPackage` nếu có
    for i in "${centPackage[@]}"; do
      yum install -y $i
    done

  else
    systemctl stop firewalld
    systemctl disable firewalld
    systemctl mask --now firewalld
    systemctl stop chronyd
    systemctl disable chronyd
    yum update -y
    yum install psmisc -y
    yum install htop -y
    yum upgrade -y
    [ -d /sys/firmware/efi ] && grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg || grub2-mkconfig -o /boot/grub2/grub.cfg

    # Grant execution permission for rc.local script
    chmod +x /etc/rc.local
    sed -i 's/^SELINUX=.*/SELINUX=disabled/g' /etc/selinux/config
    for i in "${centPackage[@]}"; do yum install $i -y; done
  fi

    ;;

*)
  echo "OS not supported"
  ;;
esac

echo "=== Disable chrony ==="
systemctl disable chronyd.service
systemctl stop chronyd.service

clear
echo "=== Check internet connections ==="
dig @8.8.8.8 google.com +noall +answer &> /dev/null
if [[ $? != 0 ]]; then
  echo "Cannot resolve google.com. Check UDP connection"
else
  echo "UDP connection working fine"
fi

echo ""

### Check international traffic
request_ID=$(curl -s -H "Accept: application/json" https://check-host.net/check-ping\?host\=$publicIP\&max_nodes\=3 | jq -r '."request_id"')
sleep 10

result=$(curl -s -H "Accept: application/json" https://check-host.net/check-result/$request_ID)

list_host=$(jq 'keys | .[]' <<< $result)

while IFS= read -r line; do
    OK=$(echo $result | jq ".$line" | grep "OK" | wc -l)
    echo "Host: $line ===  $OK/4"
done <<< "$list_host"

# Clear bash history and truncate wtmp file
history -c
history -w
truncate -s 0 /var/log/wtmp
echo "Bash history cleared and wtmp file truncated."


### Reboot block ###
echo -e "\n\n\n\n"
echo "Your server will reboot in 5 seconds"
sleep 1
echo "Your server will reboot in 4 seconds"
sleep 1
echo "Your server will reboot in 3 seconds"
sleep 1
echo "Your server will reboot in 2 seconds"
sleep 1
echo "Your server will reboot in 1 second"
sleep 1

/sbin/reboot