Configure OSPF dynamic routing with FRRouting for enterprise network failover

#!/usr/bin/env bash

set -euo pipefail

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

# Default values
ROUTER_ID=""
ROUTER_HOSTNAME=""
OSPF_PASSWORD="ospf-secure-$(date +%Y-%m-%d)"
NETWORKS=()

usage() {
    echo "Usage: $0 --router-id <IP> --hostname <name> [--network <network/mask>] [--password <auth_key>]"
    echo "Example: $0 --router-id 10.0.0.1 --hostname router1 --network 10.0.1.0/24 --network 192.168.1.0/24"
    exit 1
}

cleanup() {
    echo -e "${RED}[ERROR] Installation failed. Rolling back changes...${NC}"
    systemctl stop frr 2>/dev/null || true
    systemctl disable frr 2>/dev/null || true
    if [ -f /etc/frr/frr.conf.backup ]; then
        mv /etc/frr/frr.conf.backup /etc/frr/frr.conf
    fi
    if [ -f /etc/frr/daemons.backup ]; then
        mv /etc/frr/daemons.backup /etc/frr/daemons
    fi
    if [ -f /etc/sysctl.conf.backup ]; then
        mv /etc/sysctl.conf.backup /etc/sysctl.conf
        sysctl -p
    fi
}

trap cleanup ERR

# Parse arguments
while [[ $# -gt 0 ]]; do
    case $1 in
        --router-id)
            ROUTER_ID="$2"
            shift 2
            ;;
        --hostname)
            ROUTER_HOSTNAME="$2"
            shift 2
            ;;
        --network)
            NETWORKS+=("$2")
            shift 2
            ;;
        --password)
            OSPF_PASSWORD="$2"
            shift 2
            ;;
        -h|--help)
            usage
            ;;
        *)
            echo -e "${RED}Unknown option: $1${NC}"
            usage
            ;;
    esac
done

# Validate required arguments
if [[ -z "$ROUTER_ID" || -z "$ROUTER_HOSTNAME" ]]; then
    echo -e "${RED}Error: --router-id and --hostname are required${NC}"
    usage
fi

if [[ ${#NETWORKS[@]} -eq 0 ]]; then
    echo -e "${YELLOW}Warning: No networks specified. You'll need to configure them manually.${NC}"
fi

# Check if running as root or with sudo
if [[ $EUID -ne 0 ]]; then
    echo -e "${RED}This script must be run as root or with sudo${NC}"
    exit 1
fi

echo -e "${GREEN}Starting FRRouting OSPF installation and configuration${NC}"

# Auto-detect distribution
echo -e "${YELLOW}[1/10] Detecting operating system...${NC}"
if [ -f /etc/os-release ]; then
    . /etc/os-release
    case "$ID" in
        ubuntu|debian)
            PKG_MGR="apt"
            PKG_UPDATE="apt update"
            PKG_INSTALL="apt install -y"
            PKG_UPGRADE="apt upgrade -y"
            ;;
        almalinux|rocky|centos|rhel|ol|fedora)
            PKG_MGR="dnf"
            PKG_UPDATE="dnf check-update || true"
            PKG_INSTALL="dnf install -y"
            PKG_UPGRADE="dnf upgrade -y"
            ;;
        amzn)
            PKG_MGR="yum"
            PKG_UPDATE="yum check-update || true"
            PKG_INSTALL="yum install -y"
            PKG_UPGRADE="yum upgrade -y"
            ;;
        *)
            echo -e "${RED}Unsupported distribution: $ID${NC}"
            exit 1
            ;;
    esac
    echo -e "${GREEN}Detected: $PRETTY_NAME${NC}"
else
    echo -e "${RED}Cannot detect operating system${NC}"
    exit 1
fi

# Update system packages
echo -e "${YELLOW}[2/10] Updating system packages...${NC}"
$PKG_UPDATE
$PKG_UPGRADE

# Install FRRouting
echo -e "${YELLOW}[3/10] Installing FRRouting...${NC}"
if [[ "$PKG_MGR" == "apt" ]]; then
    $PKG_INSTALL frr frr-pythontools
else
    $PKG_INSTALL frr frr-pythontools
fi

# Backup original configuration files
echo -e "${YELLOW}[4/10] Backing up original configurations...${NC}"
if [ -f /etc/sysctl.conf ]; then
    cp /etc/sysctl.conf /etc/sysctl.conf.backup
fi
if [ -f /etc/frr/daemons ]; then
    cp /etc/frr/daemons /etc/frr/daemons.backup
fi
if [ -f /etc/frr/frr.conf ]; then
    cp /etc/frr/frr.conf /etc/frr/frr.conf.backup
fi

# Enable IP forwarding
echo -e "${YELLOW}[5/10] Enabling IP forwarding...${NC}"
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

# Configure FRRouting daemons
echo -e "${YELLOW}[6/10] Configuring FRRouting daemons...${NC}"
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
staticd=yes
vrrpd=no
EOF

# Create OSPF configuration
echo -e "${YELLOW}[7/10] Creating OSPF configuration...${NC}"
cat > /etc/frr/frr.conf << EOF
!
! FRR configuration for OSPF
!
frr version 8.1
frr defaults traditional
!
hostname ${ROUTER_HOSTNAME}
password zebra
enable password zebra
!
router ospf
 ospf router-id ${ROUTER_ID}
EOF

# Add networks to OSPF configuration
for network in "${NETWORKS[@]}"; do
    echo " network ${network} area 0" >> /etc/frr/frr.conf
done

cat >> /etc/frr/frr.conf << EOF
 area 0 authentication message-digest
 passive-interface lo
!
EOF

# Add interface authentication (for first two interfaces if they exist)
if ip link show eth0 >/dev/null 2>&1; then
    cat >> /etc/frr/frr.conf << EOF
interface eth0
 ip ospf message-digest-key 1 md5 ${OSPF_PASSWORD}
!
EOF
fi

if ip link show eth1 >/dev/null 2>&1; then
    cat >> /etc/frr/frr.conf << EOF
interface eth1
 ip ospf message-digest-key 1 md5 ${OSPF_PASSWORD}
!
EOF
fi

echo "line vty" >> /etc/frr/frr.conf
echo "!" >> /etc/frr/frr.conf

# Set proper file permissions
echo -e "${YELLOW}[8/10] Setting file permissions...${NC}"
chown frr:frr /etc/frr/frr.conf
chmod 640 /etc/frr/frr.conf
chown frr:frr /etc/frr/daemons
chmod 644 /etc/frr/daemons

# Configure firewall if firewalld is active
if systemctl is-active firewalld >/dev/null 2>&1; then
    echo -e "${YELLOW}[9/10] Configuring firewall for OSPF...${NC}"
    firewall-cmd --permanent --add-protocol=ospf 2>/dev/null || true
    firewall-cmd --permanent --add-port=89/tcp 2>/dev/null || true
    firewall-cmd --reload 2>/dev/null || true
fi

# Start and enable FRRouting
echo -e "${YELLOW}[10/10] Starting FRRouting service...${NC}"
systemctl enable frr
systemctl start frr

# Verification checks
echo -e "${YELLOW}Performing verification checks...${NC}"
sleep 3

if systemctl is-active frr >/dev/null 2>&1; then
    echo -e "${GREEN}✓ FRRouting service is running${NC}"
else
    echo -e "${RED}✗ FRRouting service failed to start${NC}"
    exit 1
fi

if grep -q "net.ipv4.ip_forward=1" /etc/sysctl.conf && [ "$(sysctl -n net.ipv4.ip_forward)" = "1" ]; then
    echo -e "${GREEN}✓ IP forwarding is enabled${NC}"
else
    echo -e "${RED}✗ IP forwarding is not properly configured${NC}"
    exit 1
fi

if vtysh -c "show running-config" | grep -q "router ospf" 2>/dev/null; then
    echo -e "${GREEN}✓ OSPF configuration is loaded${NC}"
else
    echo -e "${YELLOW}⚠ OSPF configuration may need manual verification${NC}"
fi

echo -e "${GREEN}FRRouting OSPF installation completed successfully!${NC}"
echo -e "${YELLOW}Configuration details:${NC}"
echo "  Router ID: ${ROUTER_ID}"
echo "  Hostname: ${ROUTER_HOSTNAME}"
echo "  Networks: ${NETWORKS[*]}"
echo "  Authentication key: ${OSPF_PASSWORD}"
echo ""
echo -e "${YELLOW}Next steps:${NC}"
echo "1. Use 'sudo vtysh' to access the FRRouting shell"
echo "2. Run 'show ip ospf neighbor' to verify OSPF neighbors"
echo "3. Run 'show ip route ospf' to see OSPF learned routes"
echo "4. Configure additional networks with: vtysh -c 'configure terminal' -c 'router ospf' -c 'network <network>/<mask> area <area>'"