rego-tunnel: parameterize net + add DHCP static lease

2025-12-28 22:56:51 +00:00
parent 919f5904f8
commit 2d98ca843f
7 changed files with 169 additions and 29 deletions
--- a/apps/rego-tunnel/build/Dockerfile
+++ b/apps/rego-tunnel/build/Dockerfile
@@ -2,7 +2,7 @@ FROM ubuntu:24.04

 ENV DEBIAN_FRONTEND=noninteractive

-RUN apt-get update && apt-get install -y qemu-system-x86 qemu-utils novnc websockify openssh-server supervisor iproute2 bridge-utils iptables nano net-tools p7zip-full && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y qemu-system-x86 qemu-utils novnc websockify openssh-server supervisor iproute2 bridge-utils iptables nano net-tools p7zip-full dnsmasq && rm -rf /var/lib/apt/lists/*

 # Setup SSH
 RUN mkdir /var/run/sshd && echo 'root:vmpassword' | chpasswd && sed -i 's/#PermitRootLogin prohibit-password/PermitRootLogin yes/' /etc/ssh/sshd_config
@@ -12,6 +12,7 @@ WORKDIR /vm
 COPY supervisord.conf /etc/supervisor/conf.d/supervisord.conf
 COPY start-vm.sh /usr/local/bin/start-vm.sh
 COPY setup-network.sh /usr/local/bin/setup-network.sh
-RUN chmod +x /usr/local/bin/start-vm.sh /usr/local/bin/setup-network.sh
+COPY start-dnsmasq.sh /usr/local/bin/start-dnsmasq.sh
+RUN chmod +x /usr/local/bin/start-vm.sh /usr/local/bin/setup-network.sh /usr/local/bin/start-dnsmasq.sh

 CMD ["/usr/bin/supervisord", "-c", "/etc/supervisor/conf.d/supervisord.conf"]
--- a/apps/rego-tunnel/build/setup-network.sh
+++ b/apps/rego-tunnel/build/setup-network.sh
@@ -1,10 +1,21 @@
 #!/bin/bash
 # Setup TAP/Bridge networking for QEMU VM
-# Bridge: 100.100.0.1/24
-# VM will be: 100.100.0.2/24
+# Defaults:
+#   BRIDGE_NAME=br-rego-vpn
+#   TAP_NAME=tap0
+#   BRIDGE_CIDR=100.100.0.1/24
+#   VM_NET_IP=100.100.0.2
+#   VM_SUBNET=100.100.0.0/24

 set -e

+BRIDGE_NAME="${BRIDGE_NAME:-br-rego-vpn}"
+TAP_NAME="${TAP_NAME:-tap0}"
+BRIDGE_CIDR="${BRIDGE_CIDR:-100.100.0.1/24}"
+VM_NET_IP="${VM_NET_IP:-100.100.0.2}"
+VM_SUBNET="${VM_SUBNET:-100.100.0.0/24}"
+TARGET_IP="${TARGET_IP:-10.35.33.230}"
+
 # Pick the outbound interface based on the container's default route.
 # (In Docker, this is not always eth1 when multiple networks are attached.)
 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 $(i+1); exit}}')"
@@ -13,44 +24,44 @@ if [ -z "${WAN_IF}" ]; then
 fi

 # Create bridge if not exists
-if ! ip link show br0 &>/dev/null; then
-    ip link add br0 type bridge
-    ip addr add 100.100.0.1/24 dev br0
-    ip link set br0 up
-    echo "Bridge br0 created with IP 100.100.0.1/24"
+if ! ip link show "$BRIDGE_NAME" &>/dev/null; then
+    ip link add "$BRIDGE_NAME" type bridge
+    ip addr add "$BRIDGE_CIDR" dev "$BRIDGE_NAME"
+    ip link set "$BRIDGE_NAME" up
+    echo "Bridge $BRIDGE_NAME created with IP $BRIDGE_CIDR"
 fi

 # Create TAP device if not exists
-if ! ip link show tap0 &>/dev/null; then
-    ip tuntap add tap0 mode tap
-    ip link set tap0 master br0
-    ip link set tap0 up
-    echo "TAP device tap0 created and attached to br0"
+if ! ip link show "$TAP_NAME" &>/dev/null; then
+    ip tuntap add "$TAP_NAME" mode tap
+    ip link set "$TAP_NAME" master "$BRIDGE_NAME"
+    ip link set "$TAP_NAME" up
+    echo "TAP device $TAP_NAME created and attached to $BRIDGE_NAME"
 fi

 # Enable IP forwarding
 echo 1 > /proc/sys/net/ipv4/ip_forward

 # Setup NAT/masquerade for outbound traffic from VM
-iptables -t nat -C POSTROUTING -s 100.100.0.0/24 -o "$WAN_IF" -j MASQUERADE 2>/dev/null || \
-    iptables -t nat -A POSTROUTING -s 100.100.0.0/24 -o "$WAN_IF" -j MASQUERADE
+iptables -t nat -C POSTROUTING -s "$VM_SUBNET" -o "$WAN_IF" -j MASQUERADE 2>/dev/null || \
+    iptables -t nat -A POSTROUTING -s "$VM_SUBNET" -o "$WAN_IF" -j MASQUERADE

 # Ensure forwarding between the VM bridge and outbound interface
-iptables -C FORWARD -i br0 -o "$WAN_IF" -j ACCEPT 2>/dev/null || \
-    iptables -A FORWARD -i br0 -o "$WAN_IF" -j ACCEPT
-iptables -C FORWARD -i "$WAN_IF" -o br0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT 2>/dev/null || \
-    iptables -A FORWARD -i "$WAN_IF" -o br0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
+iptables -C FORWARD -i "$BRIDGE_NAME" -o "$WAN_IF" -j ACCEPT 2>/dev/null || \
+    iptables -A FORWARD -i "$BRIDGE_NAME" -o "$WAN_IF" -j ACCEPT
+iptables -C FORWARD -i "$WAN_IF" -o "$BRIDGE_NAME" -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT 2>/dev/null || \
+    iptables -A FORWARD -i "$WAN_IF" -o "$BRIDGE_NAME" -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

-# Forward traffic destined for VPN networks to VM (10.35.33.230 = IBM i)
+# Forward traffic destined for VPN networks to VM (TARGET_IP defaults to IBM i)
 # The VM will route this through its VPN tunnel
-iptables -C FORWARD -d 10.35.33.230 -j ACCEPT 2>/dev/null ||     iptables -A FORWARD -d 10.35.33.230 -j ACCEPT
-iptables -C FORWARD -s 10.35.33.230 -j ACCEPT 2>/dev/null ||     iptables -A FORWARD -s 10.35.33.230 -j ACCEPT
+iptables -C FORWARD -d "$TARGET_IP" -j ACCEPT 2>/dev/null ||     iptables -A FORWARD -d "$TARGET_IP" -j ACCEPT
+iptables -C FORWARD -s "$TARGET_IP" -j ACCEPT 2>/dev/null ||     iptables -A FORWARD -s "$TARGET_IP" -j ACCEPT

-# Route to IBM i through VM
-ip route add 10.35.33.230 via 100.100.0.2 2>/dev/null || true
+# Route to TARGET_IP through VM
+ip route add "$TARGET_IP" via "$VM_NET_IP" 2>/dev/null || true

 echo "Network setup complete"
-echo "Bridge: br0 = 100.100.0.1/24"
-echo "TAP: tap0 attached to br0"
-echo "Route: 10.35.33.230 via 100.100.0.2 (VM)"
+echo "Bridge: $BRIDGE_NAME = $BRIDGE_CIDR"
+echo "TAP: $TAP_NAME attached to $BRIDGE_NAME"
+echo "Route: $TARGET_IP via $VM_NET_IP (VM)"
 echo "Outbound interface: ${WAN_IF}"
--- a/apps/rego-tunnel/build/start-dnsmasq.sh
+++ b/apps/rego-tunnel/build/start-dnsmasq.sh
@@ -0,0 +1,34 @@
+#!/bin/bash
+set -euo pipefail
+
+BRIDGE_NAME="${BRIDGE_NAME:-br-rego-vpn}"
+BRIDGE_CIDR="${BRIDGE_CIDR:-100.100.0.1/24}"
+VM_NET_IP="${VM_NET_IP:-100.100.0.2}"
+VM_MAC="${VM_MAC:-52:54:00:12:34:56}"
+
+LEASE_TIME="${LEASE_TIME:-12h}"
+DNS_SERVERS="${DNS_SERVERS:-1.1.1.1,8.8.8.8}"
+
+GATEWAY_IP="${BRIDGE_CIDR%%/*}"
+
+mkdir -p /etc/dnsmasq.d
+
+cat > /etc/dnsmasq.d/rego.conf <<EOF
+interface=${BRIDGE_NAME}
+bind-interfaces
+except-interface=lo
+
+dhcp-authoritative
+log-dhcp
+
+dhcp-range=${VM_NET_IP},${VM_NET_IP},${LEASE_TIME}
+dhcp-option=option:router,${GATEWAY_IP}
+dhcp-option=option:dns-server,${DNS_SERVERS}
+
+# Static lease for the VM
+# (VM must use DHCP for this to take effect)
+dhcp-host=${VM_MAC},${VM_NET_IP}
+EOF
+
+echo "[rego-tunnel] dnsmasq on ${BRIDGE_NAME} gateway=${GATEWAY_IP} lease ${VM_MAC} -> ${VM_NET_IP}"
+exec dnsmasq --no-daemon --conf-file=/etc/dnsmasq.d/rego.conf
--- a/apps/rego-tunnel/build/start-vm.sh
+++ b/apps/rego-tunnel/build/start-vm.sh
@@ -23,6 +23,8 @@ fi
 # Wait for network setup
 sleep 2

+TAP_NAME="${TAP_NAME:-tap0}"
+
 exec qemu-system-x86_64 \
 	-enable-kvm \
 	-cpu host \
@@ -31,7 +33,7 @@ exec qemu-system-x86_64 \
 	-hda /vm/linux-vm.qcow2 \
 	-fsdev local,id=fsdev0,path=/shared,security_model=none,multidevs=remap \
 	-device virtio-9p-pci,fsdev=fsdev0,mount_tag=shared \
-	-netdev tap,id=net0,ifname=tap0,script=no,downscript=no \
+	-netdev tap,id=net0,ifname="$TAP_NAME",script=no,downscript=no \
 	-device virtio-net-pci,netdev=net0,mac=52:54:00:12:34:56 \
 	-vnc :0 \
 	-vga virtio \
--- a/apps/rego-tunnel/build/supervisord.conf
+++ b/apps/rego-tunnel/build/supervisord.conf
@@ -13,6 +13,16 @@ stdout_logfile_maxbytes=0
 stderr_logfile=/dev/stderr
 stderr_logfile_maxbytes=0

+[program:dnsmasq]
+command=/usr/local/bin/start-dnsmasq.sh
+autostart=true
+autorestart=true
+priority=5
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
+
 [program:sshd]
 command=/usr/sbin/sshd -D
 autostart=true