57 lines
2.1 KiB
Bash
57 lines
2.1 KiB
Bash
#!/bin/bash
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# Setup TAP/Bridge networking for QEMU VM
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# Bridge: 100.100.0.1/24
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# VM will be: 100.100.0.2/24
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set -e
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# Pick the outbound interface based on the container's default route.
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# (In Docker, this is not always eth0 when multiple networks are attached.)
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WAN_IF="$(ip route show default 0.0.0.0/0 2>/dev/null | awk '{for(i=1;i<=NF;i++) if($i=="dev"){print $(i+1); exit}}')"
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if [ -z "${WAN_IF}" ]; then
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WAN_IF="eth0"
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fi
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# Create bridge if not exists
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if ! ip link show br0 &>/dev/null; then
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ip link add br0 type bridge
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ip addr add 100.100.0.1/24 dev br0
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ip link set br0 up
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echo "Bridge br0 created with IP 100.100.0.1/24"
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fi
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# Create TAP device if not exists
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if ! ip link show tap0 &>/dev/null; then
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ip tuntap add tap0 mode tap
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ip link set tap0 master br0
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ip link set tap0 up
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echo "TAP device tap0 created and attached to br0"
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fi
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# Enable IP forwarding
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echo 1 > /proc/sys/net/ipv4/ip_forward
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# Setup NAT/masquerade for outbound traffic from VM
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iptables -t nat -C POSTROUTING -s 100.100.0.0/24 -o "$WAN_IF" -j MASQUERADE 2>/dev/null || \
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iptables -t nat -A POSTROUTING -s 100.100.0.0/24 -o "$WAN_IF" -j MASQUERADE
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# Ensure forwarding between the VM bridge and outbound interface
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iptables -C FORWARD -i br0 -o "$WAN_IF" -j ACCEPT 2>/dev/null || \
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iptables -A FORWARD -i br0 -o "$WAN_IF" -j ACCEPT
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iptables -C FORWARD -i "$WAN_IF" -o br0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT 2>/dev/null || \
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iptables -A FORWARD -i "$WAN_IF" -o br0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
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# Forward traffic destined for VPN networks to VM (10.35.33.230 = IBM i)
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# The VM will route this through its VPN tunnel
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iptables -C FORWARD -d 10.35.33.230 -j ACCEPT 2>/dev/null || iptables -A FORWARD -d 10.35.33.230 -j ACCEPT
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iptables -C FORWARD -s 10.35.33.230 -j ACCEPT 2>/dev/null || iptables -A FORWARD -s 10.35.33.230 -j ACCEPT
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# Route to IBM i through VM
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ip route add 10.35.33.230 via 100.100.0.2 2>/dev/null || true
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echo "Network setup complete"
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echo "Bridge: br0 = 100.100.0.1/24"
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echo "TAP: tap0 attached to br0"
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echo "Route: 10.35.33.230 via 100.100.0.2 (VM)"
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echo "Outbound interface: ${WAN_IF}"
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