connection.sh

#!/bin/bash
# Automatic OVPN server connection script
# Function: Automatically input private key password, username and password into connection file and connect

# Set color output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

# Set file path
OVPN_FILE="API/imCloud.ovpn"
CONFIG_FILE="API/connection_config.txt"
TEMP_OVPN_FILE="/tmp/imCloud_auto.ovpn"

# Function: Show usage
show_usage() {
    echo "Usage:"
    echo "  $0                    # Use configuration file to connect"
    echo "  $0 --setup            # Set connection information (private key password, username, password)"
    echo "  $0 --disconnect       # Disconnect"
    echo ""
    echo "Configuration file location: $CONFIG_FILE"
    echo "OVPN file location: $OVPN_FILE"
}

# Function: Check necessary tools
check_requirements() {
    if ! command -v openvpn &> /dev/null; then
        sudo apt update && sudo apt upgrade -y
        sudo apt install -y openvpn
    fi
}

# Function: Set connection information
setup_connection() {
    echo -e "${YELLOW}=== Set OVPN connection information ===${NC}"
    echo ""
    
    # Check if configuration file exists
    if [ -f "$CONFIG_FILE" ]; then
        echo "Found existing configuration file, will update configuration..."
        source "$CONFIG_FILE"
    fi
    
    # Read private key password
    if [ -z "$PRIVATE_KEY_PASSWORD" ]; then
        read -sp "Please enter the private key password: " key_password
        echo ""
        PRIVATE_KEY_PASSWORD="$key_password"
    else
        read -sp "Please enter the private key password (press Enter to keep unchanged): " key_password
        echo ""
        if [ -n "$key_password" ]; then
            PRIVATE_KEY_PASSWORD="$key_password"
        fi
    fi
    
    # Read username
    if [ -z "$OVPN_USERNAME" ]; then
        read -p "Please enter the OVPN username: " username
        OVPN_USERNAME="$username"
    else
        read -p "Please enter the OVPN username (currently: $OVPN_USERNAME, press Enter to keep unchanged): " username
        if [ -n "$username" ]; then
            OVPN_USERNAME="$username"
        fi
    fi
    
    # Read password
    if [ -z "$OVPN_PASSWORD" ]; then
        read -sp "Please enter the OVPN password: " password
        echo ""
        OVPN_PASSWORD="$password"
    else
        read -sp "Please enter the OVPN password (press Enter to keep unchanged): " password
        echo ""
        if [ -n "$password" ]; then
            OVPN_PASSWORD="$password"
        fi
    fi
    
    # Read OVPN server address (optional)
    if [ -z "$OVPN_SERVER" ]; then
        read -p "Please enter the OVPN server address (optional, press Enter to skip): " server
        OVPN_SERVER="$server"
    else
        read -p "Please enter the OVPN server address (currently: $OVPN_SERVER, press Enter to keep unchanged): " server
        if [ -n "$server" ]; then
            OVPN_SERVER="$server"
        fi
    fi
    
    # Save configuration file
    cat > "$CONFIG_FILE" << EOF
# OVPN connection configuration file
# This file contains sensitive information, please do not share or submit to version control system

PRIVATE_KEY_PASSWORD="$PRIVATE_KEY_PASSWORD"
OVPN_USERNAME="$OVPN_USERNAME"
OVPN_PASSWORD="$OVPN_PASSWORD"
OVPN_SERVER="$OVPN_SERVER"
EOF
    
    # Set file permissions (only owner can read and write)
    chmod 600 "$CONFIG_FILE"
    
    echo -e "${GREEN}Configuration saved to $CONFIG_FILE${NC}"
    echo ""
}

# Function: Create temporary OVPN file
create_temp_ovpn() {
    # Check if original OVPN file exists
    if [ ! -f "$OVPN_FILE" ]; then
        echo -e "${YELLOW}Warning: OVPN file does not exist: $OVPN_FILE${NC}"
        echo "Creating basic OVPN configuration file..."
        
        # Create basic OVPN configuration file
        cat > "$OVPN_FILE" << EOF
# OVPN connection configuration file
client
dev tun
proto udp
resolv-retry infinite
nobind
persist-key
persist-tun
verb 3
EOF
        
        if [ -n "$OVPN_SERVER" ]; then
            echo "remote $OVPN_SERVER 1194" >> "$OVPN_FILE"
        fi
        
        echo ""
        echo -e "${YELLOW}Please manually edit $OVPN_FILE to add complete OVPN settings${NC}"
        echo ""
    fi
    
    # Copy original OVPN file to temporary file
    cp "$OVPN_FILE" "$TEMP_OVPN_FILE"
    
    # Create authentication file (username and password)
    AUTH_FILE="/tmp/ovpn_auth_$$.txt"
    echo "$OVPN_USERNAME" > "$AUTH_FILE"
    echo "$OVPN_PASSWORD" >> "$AUTH_FILE"
    chmod 600 "$AUTH_FILE"
    
    # Add authentication settings to OVPN file
    echo "auth-user-pass $AUTH_FILE" >> "$TEMP_OVPN_FILE"
    
    # Create private key password file
    KEY_PASS_FILE="/tmp/ovpn_keypass_$$.txt"
    echo "$PRIVATE_KEY_PASSWORD" > "$KEY_PASS_FILE"
    chmod 600 "$KEY_PASS_FILE"
    
    echo "$AUTH_FILE|$KEY_PASS_FILE"  # Return authentication file and private key password file path for subsequent cleanup
}

# Function: Connect to OVPN
connect_ovpn() {
    # Check if configuration file exists
    if [ ! -f "$CONFIG_FILE" ]; then
        echo -e "${RED}Error: Configuration file does not exist: $CONFIG_FILE${NC}"
        echo "Please execute: $0 --setup"
        exit 1
    fi
    
    # Load configuration file
    source "$CONFIG_FILE"
    
    # Check necessary variables
    if [ -z "$PRIVATE_KEY_PASSWORD" ] || [ -z "$OVPN_USERNAME" ] || [ -z "$OVPN_PASSWORD" ]; then
        echo -e "${RED}Error: Configuration file is incomplete${NC}"
        echo "Please execute: $0 --setup"
        exit 1
    fi
    
    # Check if already connected
    if pgrep -x openvpn > /dev/null; then
        echo -e "${YELLOW}Warning: OVPN connection already exists${NC}"
        read -p "Do you want to disconnect the existing connection and reconnect? (y/N): " answer
        if [ "$answer" = "y" ] || [ "$answer" = "Y" ]; then
            disconnect_ovpn
        else
            exit 0
        fi
    fi
    
    echo -e "${GREEN}Creating OVPN connection...${NC}"
    
    # Create temporary OVPN file
    FILES=$(create_temp_ovpn)
    AUTH_FILE=$(echo "$FILES" | cut -d'|' -f1)
    KEY_PASS_FILE=$(echo "$FILES" | cut -d'|' -f2)
    
    # Execute OVPN connection (background execution)
    echo "Using configuration file: $TEMP_OVPN_FILE"
    echo "Authentication file: $AUTH_FILE"
    echo "Private key password file: $KEY_PASS_FILE"
    echo ""
    
    # Execute with root permissions (if needed)
    if [ "$EUID" -eq 0 ]; then
        openvpn --config "$TEMP_OVPN_FILE" --askpass "$KEY_PASS_FILE" --daemon
    else
        echo "Trying to execute with sudo permissions..."
        sudo openvpn --config "$TEMP_OVPN_FILE" --askpass "$KEY_PASS_FILE" --daemon
    fi
    
    # Wait for connection to be established
    sleep 2
    
    # Check connection status
    if pgrep -x openvpn > /dev/null; then
        echo -e "${GREEN}OVPN connection has been started${NC}"
        echo "Use 'sudo killall openvpn' or execute '$0 --disconnect' to disconnect"
        
        # Clean up temporary authentication files (delayed cleanup, ensure OVPN has read)
        (sleep 5 && rm -f "$AUTH_FILE" "$KEY_PASS_FILE") &
    else
        echo -e "${RED}Error: OVPN connection failed to start${NC}"
        echo "Please check:"
        echo "  1. OVPN configuration file is correct"
        echo "  2. Private key password is correct"
        echo "  3. Username and password are correct"
        echo "  4. System logs: sudo journalctl -u openvpn -n 50"
        rm -f "$AUTH_FILE" "$KEY_PASS_FILE" "$TEMP_OVPN_FILE"
        exit 1
    fi
}

# Function: Disconnect OVPN
disconnect_ovpn() {
    echo -e "${YELLOW}Disconnecting OVPN connection...${NC}"
    
    if pgrep -x openvpn > /dev/null; then
        if [ "$EUID" -eq 0 ]; then
            killall openvpn
        else
            sudo killall openvpn
        fi
        
        sleep 1
        
        if ! pgrep -x openvpn > /dev/null; then
            echo -e "${GREEN}OVPN connection has been disconnected${NC}"
        else
            echo -e "${RED}Error: Unable to disconnect${NC}"
            exit 1
        fi
    else
        echo -e "${YELLOW}No active OVPN connection${NC}"
    fi
    
    # Clean up temporary files
    rm -f /tmp/ovpn_auth_*.txt /tmp/ovpn_keypass_*.txt "$TEMP_OVPN_FILE"
}

# Main program
main() {
    # Check necessary tools
    check_requirements
    
    # Parse command line parameters
    case "$1" in
        --setup|--config)
            setup_connection
            ;;
        --disconnect|--stop)
            disconnect_ovpn
            ;;
        --help|-h)
            show_usage
            ;;
        "")
            connect_ovpn
            ;;
        *)
            echo -e "${RED}Error: Unknown parameter: $1${NC}"
            show_usage
            exit 1
            ;;
    esac
}

# Execute main program
main "$@"