Configure OSPF with FRRouting 10 for dynamic routing protocols and network failover

#!/usr/bin/env bash
set -euo pipefail

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

# Configuration variables
ROUTER_ID="${1:-203.0.113.10}"
ETH0_IP="${2:-203.0.113.10/24}"
ETH1_IP="${3:-192.168.1.1/24}"
OSPF_PASSWORD="${4:-SecureOSPFKey123}"

# Function to print colored output
print_status() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

print_warning() {
    echo -e "${YELLOW}[WARN]${NC} $1"
}

print_error() {
    echo -e "${RED}[ERROR]${NC} $1" >&2
}

# Usage message
usage() {
    echo "Usage: $0 [ROUTER_ID] [ETH0_IP] [ETH1_IP] [OSPF_PASSWORD]"
    echo "Example: $0 203.0.113.10 203.0.113.10/24 192.168.1.1/24 MySecureKey"
    exit 1
}

# Cleanup function
cleanup() {
    print_error "Installation failed. Cleaning up..."
    systemctl stop frr 2>/dev/null || true
    systemctl disable frr 2>/dev/null || true
}

# Trap for cleanup on error
trap cleanup ERR

# Check if running as root or with sudo
if [[ $EUID -ne 0 ]]; then
    print_error "This script must be run as root or with sudo"
    exit 1
fi

# Detect distribution
if [ -f /etc/os-release ]; then
    . /etc/os-release
    case "$ID" in
        ubuntu|debian) 
            PKG_MGR="apt"
            PKG_UPDATE="apt update"
            PKG_UPGRADE="apt upgrade -y"
            PKG_INSTALL="apt install -y"
            ;;
        almalinux|rocky|centos|rhel|ol|fedora) 
            PKG_MGR="dnf"
            PKG_UPDATE="dnf update -y"
            PKG_UPGRADE=""
            PKG_INSTALL="dnf install -y"
            ;;
        amzn) 
            PKG_MGR="yum"
            PKG_UPDATE="yum update -y"
            PKG_UPGRADE=""
            PKG_INSTALL="yum install -y"
            ;;
        *) 
            print_error "Unsupported distribution: $ID"
            exit 1
            ;;
    esac
else
    print_error "Cannot detect distribution"
    exit 1
fi

print_status "[1/8] Updating system packages..."
$PKG_UPDATE
if [[ -n "$PKG_UPGRADE" ]]; then
    $PKG_UPGRADE
fi

print_status "[2/8] Installing FRRouting 10..."
case "$PKG_MGR" in
    apt)
        curl -s https://deb.frrouting.org/frr/keys.asc | gpg --dearmor > /usr/share/keyrings/frrouting.gpg
        echo "deb [signed-by=/usr/share/keyrings/frrouting.gpg] https://deb.frrouting.org/frr $(lsb_release -s -c) frr-stable" > /etc/apt/sources.list.d/frr.list
        apt update
        $PKG_INSTALL frr frr-pythontools
        ;;
    dnf|yum)
        $PKG_INSTALL "https://rpm.frrouting.org/repo/$(rpm -E %rhel)-repo-1-0.el$(rpm -E %rhel).noarch.rpm"
        $PKG_INSTALL frr frr-pythontools
        ;;
esac

print_status "[3/8] Configuring FRRouting daemons..."
cat > /etc/frr/daemons << 'EOF'
bgpd=no
ospfd=yes
ospf6d=no
ripd=no
ripngd=no
isisd=no
pimd=no
ldpd=no
nhrpd=no
eigrpd=no
babeld=no
sharpd=no
pbrd=no
bfdd=no
fabricd=no
vrrpd=no
pathd=no
vtysh_enable=yes
zebra_options="-s 90000000"
ospfd_options="-A 127.0.0.1"
EOF

print_status "[4/8] Creating OSPF configuration..."
cat > /etc/frr/frr.conf << EOF
frr version 10.0
frr defaults traditional
hostname $(hostname)
log syslog informational
service integrated-vtysh-config
!
interface eth0
 ip address $ETH0_IP
 ip ospf area 0.0.0.0
 ip ospf message-digest-key 1 md5 $OSPF_PASSWORD
 ip ospf hello-interval 5
 ip ospf dead-interval 20
 ip ospf priority 100
!
interface eth1
 ip address $ETH1_IP
 ip ospf area 0.0.0.1
 ip ospf message-digest-key 1 md5 $OSPF_PASSWORD
 ip ospf hello-interval 10
 ip ospf dead-interval 40
 ip ospf priority 50
!
router ospf
 ospf router-id $ROUTER_ID
 network $(echo $ETH0_IP | cut -d'/' -f1 | sed 's/\.[0-9]*$/\.0/')/$(echo $ETH0_IP | cut -d'/' -f2) area 0.0.0.0
 network $(echo $ETH1_IP | cut -d'/' -f1 | sed 's/\.[0-9]*$/\.0/')/$(echo $ETH1_IP | cut -d'/' -f2) area 0.0.0.1
 area 0.0.0.0 authentication message-digest
 area 0.0.0.1 authentication message-digest
 area 0.0.0.1 stub
 passive-interface default
 no passive-interface eth0
 no passive-interface eth1
!
line vty
!
end
EOF

print_status "[5/8] Setting file permissions and ownership..."
chown frr:frr /etc/frr/frr.conf
chmod 640 /etc/frr/frr.conf
chown frr:frrvty /etc/frr/vtysh.conf 2>/dev/null || true
chmod 640 /etc/frr/vtysh.conf 2>/dev/null || true

print_status "[6/8] Enabling IP forwarding..."
if ! grep -q "net.ipv4.ip_forward=1" /etc/sysctl.conf; then
    echo 'net.ipv4.ip_forward=1' >> /etc/sysctl.conf
fi
if ! grep -q "net.ipv6.conf.all.forwarding=1" /etc/sysctl.conf; then
    echo 'net.ipv6.conf.all.forwarding=1' >> /etc/sysctl.conf
fi
sysctl -p

print_status "[7/8] Starting and enabling FRRouting..."
systemctl enable frr
systemctl start frr

# Wait for service to start
sleep 3

print_status "[8/8] Verifying installation..."
if systemctl is-active --quiet frr; then
    print_status "FRRouting service is running"
else
    print_error "FRRouting service failed to start"
    exit 1
fi

# Test OSPF configuration
if vtysh -c "show ip ospf neighbor" >/dev/null 2>&1; then
    print_status "OSPF daemon is responding"
else
    print_warning "OSPF daemon may not be fully initialized yet"
fi

# Firewall configuration hints
case "$ID" in
    ubuntu|debian)
        if command -v ufw >/dev/null 2>&1; then
            print_warning "Configure UFW: ufw allow from 224.0.0.5/32 to any port 89"
        fi
        ;;
    *)
        if command -v firewall-cmd >/dev/null 2>&1; then
            print_warning "Configure firewall: firewall-cmd --permanent --add-protocol=ospf && firewall-cmd --reload"
        fi
        ;;
esac

print_status "FRRouting OSPF installation completed successfully!"
print_status "Router ID: $ROUTER_ID"
print_status "Management: sudo vtysh"
print_status "Status: sudo systemctl status frr"
print_status "OSPF neighbors: sudo vtysh -c 'show ip ospf neighbor'"

# Disable trap
trap - ERR