FROM --platform=linux/amd64 alpine:3.19

LABEL maintainer="GNS3 User"
LABEL description="Lightweight Linux appliance for GNS3 with VLAN and IP forwarding support"

# Install essential network tools
RUN apk add --no-cache \
    bash \
    iproute2 \
    iptables \
    tcpdump \
    dhclient \
    bridge-utils

# Load VLAN module (8021q) at boot
RUN echo "8021q" >> /etc/modules

# Create startup script to enable VLAN and IP forwarding
RUN cat > /usr/local/bin/startup.sh <<'EOF'
#!/bin/bash

# Load VLAN module
modprobe 8021q 2>/dev/null

# Enable IP forwarding
sysctl -w net.ipv4.ip_forward=1 >/dev/null 2>&1
sysctl -w net.ipv6.conf.all.forwarding=1 >/dev/null 2>&1

# Bring up all network interfaces
for iface in /sys/class/net/*; do
    ifname=$(basename $iface)
    if [ "$ifname" != "lo" ]; then
        ip link set $ifname up
    fi
done

# Start shell
exec /bin/bash
EOF

RUN chmod +x /usr/local/bin/startup.sh

WORKDIR /root

CMD ["/usr/local/bin/startup.sh"]