Lukas
68c4335348
Add check_vpn_connectivity() that runs once after wg0 comes up: - Waits for handshake (up to 15s) and prints public key if missing - Measures RX bytes before/after curl to detect server-side routing issues - Tests DNS resolution and dumps resolv.conf on failure - On failure prints exact server-side commands to fix (sysctl, iptables, wg) Add PersistentKeepalive=25 to wg0.conf to keep NAT mappings alive.
368 lines
16 KiB
Bash
368 lines
16 KiB
Bash
#!/bin/bash
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set -e
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VERSION_FILE="/etc/wireguard/VERSION"
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if [ -f "$VERSION_FILE" ]; then
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VERSION=$(cat "$VERSION_FILE")
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else
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VERSION="unknown"
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fi
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echo "[init] VPN Container Entrypoint ${VERSION}"
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INTERFACE="wg0"
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MOUNT_CONFIG="/etc/wireguard/${INTERFACE}.conf"
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CONFIG_DIR="/run/wireguard"
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CONFIG_FILE="${CONFIG_DIR}/${INTERFACE}.conf"
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CHECK_INTERVAL="${HEALTH_CHECK_INTERVAL:-10}"
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CHECK_HOST="${HEALTH_CHECK_HOST:-1.1.1.1}"
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# ──────────────────────────────────────────────
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# Validate config exists, copy to writable location
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# ──────────────────────────────────────────────
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if [ ! -f "$MOUNT_CONFIG" ]; then
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echo "[error] WireGuard config not found at ${MOUNT_CONFIG}"
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echo "[error] Mount your config file: -v /path/to/your.conf:/etc/wireguard/wg0.conf:ro"
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exit 1
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fi
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mkdir -p "$CONFIG_DIR"
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cp "$MOUNT_CONFIG" "$CONFIG_FILE"
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chmod 600 "$CONFIG_FILE"
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# Extract endpoint IP and port from the config
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VPN_ENDPOINT=$(grep -i '^Endpoint' "$CONFIG_FILE" | head -1 | sed 's/.*= *//;s/:.*//;s/ //g')
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VPN_PORT=$(grep -i '^Endpoint' "$CONFIG_FILE" | head -1 | sed 's/.*://;s/ //g')
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# Extract address
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VPN_ADDRESS=$(grep -i '^Address' "$CONFIG_FILE" | head -1 | sed 's/.*= *//;s/ //g')
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if [ -z "$VPN_ENDPOINT" ] || [ -z "$VPN_PORT" ]; then
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echo "[error] Could not parse Endpoint from ${CONFIG_FILE}"
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exit 1
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fi
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echo "[init] Config: ${CONFIG_FILE}"
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echo "[init] Endpoint: ${VPN_ENDPOINT}:${VPN_PORT}"
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echo "[init] Address: ${VPN_ADDRESS}"
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# ──────────────────────────────────────────────
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# Kill switch: only allow traffic through wg0
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# ──────────────────────────────────────────────
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setup_killswitch() {
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echo "[killswitch] Setting up iptables kill switch..."
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# Flush existing rules
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iptables -F
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iptables -X
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iptables -t nat -F
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# Default policy: DROP everything
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iptables -P INPUT DROP
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iptables -P FORWARD DROP
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iptables -P OUTPUT DROP
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# Allow loopback
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iptables -A INPUT -i lo -j ACCEPT
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iptables -A OUTPUT -o lo -j ACCEPT
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# Allow traffic to/from VPN endpoint (needed to establish tunnel)
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iptables -A OUTPUT -d "$VPN_ENDPOINT" -p udp --dport "$VPN_PORT" -j ACCEPT
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iptables -A INPUT -s "$VPN_ENDPOINT" -p udp --sport "$VPN_PORT" -j ACCEPT
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# Allow all traffic through the WireGuard interface
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iptables -A INPUT -i "$INTERFACE" -j ACCEPT
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iptables -A OUTPUT -o "$INTERFACE" -j ACCEPT
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# Allow DNS (VPN DNS servers are routed through wg0; allow before routing decision)
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iptables -A OUTPUT -p udp --dport 53 -j ACCEPT
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iptables -A OUTPUT -p tcp --dport 53 -j ACCEPT
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iptables -A INPUT -p udp --sport 53 -j ACCEPT
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iptables -A INPUT -p tcp --sport 53 -j ACCEPT
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# Allow DHCP (for container networking)
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iptables -A OUTPUT -p udp --dport 67:68 -j ACCEPT
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iptables -A INPUT -p udp --sport 67:68 -j ACCEPT
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# Allow established/related connections
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iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
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iptables -A OUTPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
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# ── Allow incoming connections to exposed service ports (e.g. app on 8000) ──
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# LOCAL_PORTS can be set as env var, e.g. "8000,8080,3000"
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if [ -n "${LOCAL_PORTS:-}" ]; then
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for port in $(echo "$LOCAL_PORTS" | tr ',' ' '); do
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echo "[killswitch] Allowing incoming traffic on port ${port}"
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iptables -A INPUT -p tcp --dport "$port" -j ACCEPT
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iptables -A OUTPUT -p tcp --sport "$port" -j ACCEPT
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done
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fi
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# ── FORWARDING (so other containers can use this VPN) ──
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iptables -A FORWARD -i eth0 -o "$INTERFACE" -j ACCEPT
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iptables -A FORWARD -i "$INTERFACE" -o eth0 -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
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# NAT: masquerade traffic from other containers going out through wg0
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iptables -t nat -A POSTROUTING -o "$INTERFACE" -j MASQUERADE
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echo "[killswitch] Kill switch active. Traffic blocked if VPN drops."
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}
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# ──────────────────────────────────────────────
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# Enable IP forwarding so other containers can route through us
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# ──────────────────────────────────────────────
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enable_forwarding() {
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echo "[init] Enabling IP forwarding..."
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if cat /proc/sys/net/ipv4/ip_forward 2>/dev/null | grep -q 1; then
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echo "[init] IP forwarding already enabled."
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elif echo 1 > /proc/sys/net/ipv4/ip_forward 2>/dev/null; then
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echo "[init] IP forwarding enabled via /proc."
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else
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echo "[init] /proc read-only — relying on --sysctl net.ipv4.ip_forward=1"
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fi
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}
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# ──────────────────────────────────────────────
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# Start WireGuard manually (no wg-quick, avoids sysctl issues)
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# ──────────────────────────────────────────────
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start_vpn() {
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echo "[vpn] Starting WireGuard interface ${INTERFACE}..."
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# Create the interface
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ip link add "$INTERFACE" type wireguard
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# Apply the WireGuard config (keys, peer, endpoint)
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# We filter out Address/DNS/MTU/PreUp/PostUp/PreDown/PostDown/SaveConfig
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# AllowedIPs is kept because WireGuard needs it to know which traffic to tunnel.
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# We remove the auto-created default route afterwards and set our own.
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wg setconf "$INTERFACE" <(grep -v -i '^\(Address\|DNS\|MTU\|PreUp\|PostUp\|PreDown\|PostDown\|SaveConfig\)' "$CONFIG_FILE")
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# Log public key so it can be verified against the server's peer list
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local PUBKEY
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PUBKEY=$(wg show "$INTERFACE" public-key 2>/dev/null || echo "unknown")
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echo "[vpn] Public key: ${PUBKEY}"
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# Assign the address
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ip -4 address add "$VPN_ADDRESS" dev "$INTERFACE"
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# Set MTU
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ip link set mtu 1420 up dev "$INTERFACE"
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# Remove the auto-created default route by wg setconf (if AllowedIPs = 0.0.0.0/0)
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# We set our own routes manually to avoid breaking the endpoint connection
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ip route del default dev "$INTERFACE" 2>/dev/null || true
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# Find default gateway/interface for the endpoint route
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DEFAULT_GW=$(ip route | grep '^default' | head -1 | awk '{print $3}')
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DEFAULT_IF=$(ip route | grep '^default' | head -1 | awk '{print $5}')
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# Route VPN endpoint through the container's default gateway
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if [ -n "$DEFAULT_GW" ] && [ -n "$DEFAULT_IF" ]; then
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ip route add "$VPN_ENDPOINT/32" via "$DEFAULT_GW" dev "$DEFAULT_IF" 2>/dev/null || true
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fi
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# Parse AllowedIPs from config and add routes dynamically
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ALLOWED_IPS=$(grep -i '^AllowedIPs' "$CONFIG_FILE" | head -1 | sed 's/.*= *//;s/ //g')
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if [ -n "$ALLOWED_IPS" ]; then
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for ip in $(echo "$ALLOWED_IPS" | tr ',' ' '); do
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if [ "$ip" = "0.0.0.0/0" ]; then
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# Use the split route trick to avoid overriding the default route
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# (which would break the endpoint connection)
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ip route add 0.0.0.0/1 dev "$INTERFACE" 2>/dev/null || true
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ip route add 128.0.0.0/1 dev "$INTERFACE" 2>/dev/null || true
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else
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ip route add "$ip" dev "$INTERFACE" 2>/dev/null || true
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fi
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done
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fi
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# ── Policy routing: ensure responses to incoming LAN traffic go back via eth0 ──
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if [ -n "$DEFAULT_GW" ] && [ -n "$DEFAULT_IF" ]; then
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# Get the container's eth0 IP address (BusyBox-compatible, no grep -P)
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ETH0_IP=$(ip -4 addr show "$DEFAULT_IF" | awk '/inet / {split($2, a, "/"); print a[1]}' | head -1)
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ETH0_SUBNET=$(ip -4 route show dev "$DEFAULT_IF" | grep -v default | head -1 | awk '{print $1}')
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if [ -n "$ETH0_IP" ] && [ -n "$ETH0_SUBNET" ]; then
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echo "[vpn] Setting up policy routing for incoming traffic (${ETH0_IP} on ${DEFAULT_IF})"
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ip route add default via "$DEFAULT_GW" dev "$DEFAULT_IF" table 100 2>/dev/null || true
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ip route add "$ETH0_SUBNET" dev "$DEFAULT_IF" table 100 2>/dev/null || true
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ip rule add from "$ETH0_IP" table 100 priority 100 2>/dev/null || true
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echo "[vpn] Policy routing active — incoming connections will be routed back via ${DEFAULT_IF}"
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fi
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fi
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# Set up DNS (handle comma-separated DNS servers)
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VPN_DNS=$(grep -i '^DNS' "$CONFIG_FILE" | head -1 | sed 's/.*= *//;s/ //g')
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if [ -n "$VPN_DNS" ]; then
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# Clear resolv.conf and add each DNS server on its own line
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> /etc/resolv.conf
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for dns in $(echo "$VPN_DNS" | tr ',' ' '); do
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echo "nameserver $dns" >> /etc/resolv.conf
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done
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echo "[vpn] DNS set to: ${VPN_DNS}"
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fi
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echo "[vpn] WireGuard interface ${INTERFACE} is up."
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echo "[vpn] Routes:"
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ip route show | sed 's/^/[vpn] /'
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echo "[vpn] WireGuard status:"
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wg show "$INTERFACE" 2>/dev/null | sed 's/^/[vpn] /'
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}
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# ──────────────────────────────────────────────
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# Stop WireGuard manually
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# ──────────────────────────────────────────────
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stop_vpn() {
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echo "[vpn] Stopping WireGuard interface ${INTERFACE}..."
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# Remove routes added for AllowedIPs
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ALLOWED_IPS=$(grep -i '^AllowedIPs' "$CONFIG_FILE" | head -1 | sed 's/.*= *//;s/ //g')
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if [ -n "$ALLOWED_IPS" ]; then
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for ip in $(echo "$ALLOWED_IPS" | tr ',' ' '); do
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if [ "$ip" = "0.0.0.0/0" ]; then
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ip route del 0.0.0.0/1 dev "$INTERFACE" 2>/dev/null || true
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ip route del 128.0.0.0/1 dev "$INTERFACE" 2>/dev/null || true
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else
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ip route del "$ip" dev "$INTERFACE" 2>/dev/null || true
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fi
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done
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fi
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# Remove endpoint route
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if [ -n "$VPN_ENDPOINT" ]; then
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ip route del "$VPN_ENDPOINT/32" 2>/dev/null || true
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fi
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ip link del "$INTERFACE" 2>/dev/null || true
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}
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# ──────────────────────────────────────────────
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# Health check loop — restarts VPN if tunnel dies
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# ──────────────────────────────────────────────
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health_loop() {
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local failures=0
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local max_failures=3
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echo "[health] Starting health check (every ${CHECK_INTERVAL}s, target ${CHECK_HOST})..."
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while true; do
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sleep "$CHECK_INTERVAL"
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if curl -sf --max-time 5 "http://$CHECK_HOST" > /dev/null 2>&1; then
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if [ "$failures" -gt 0 ]; then
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echo "[health] VPN recovered."
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failures=0
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fi
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else
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failures=$((failures + 1))
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echo "[health] Check failed ($failures/$max_failures) — curl http://${CHECK_HOST} timed out"
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# Dump WireGuard stats to show if handshake is stale and how much data flows
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echo "[health] wg stats:"
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wg show "$INTERFACE" 2>/dev/null | grep -E 'latest handshake|transfer|endpoint' | sed 's/^/[health] /' || echo "[health] wg0 not found"
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echo "[health] routes:"
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ip route show | grep -E 'wg0|default' | sed 's/^/[health] /'
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if [ "$failures" -ge "$max_failures" ]; then
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echo "[health] VPN appears down. Restarting WireGuard..."
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stop_vpn
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sleep 2
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start_vpn
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failures=0
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echo "[health] WireGuard restarted."
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fi
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fi
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done
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}
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# ──────────────────────────────────────────────
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# Graceful shutdown
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# ──────────────────────────────────────────────
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cleanup() {
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echo "[shutdown] Stopping WireGuard..."
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stop_vpn
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echo "[shutdown] Flushing iptables..."
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iptables -F
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iptables -t nat -F
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echo "[shutdown] Done."
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exit 0
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}
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trap cleanup SIGTERM SIGINT
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# ──────────────────────────────────────────────
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# Startup connectivity checks — diagnose issues early
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# ──────────────────────────────────────────────
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check_vpn_connectivity() {
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echo "[check] ── Startup connectivity checks ──"
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# 1. Wait for WireGuard handshake (up to 15s)
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local elapsed=0
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local handshake_ts=0
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echo "[check] Waiting for WireGuard handshake (up to 15s)..."
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while [ "$elapsed" -lt 15 ]; do
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handshake_ts=$(wg show "$INTERFACE" latest-handshakes 2>/dev/null | awk '{print $2}' | head -1)
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if [ -n "$handshake_ts" ] && [ "$handshake_ts" != "0" ]; then
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local age=$(( $(date +%s) - handshake_ts ))
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echo "[check] OK Handshake established ${age}s ago"
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break
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fi
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sleep 1
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elapsed=$((elapsed + 1))
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done
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if [ "$elapsed" -ge 15 ]; then
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echo "[check] FAIL No WireGuard handshake after 15s — tunnel is not up"
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echo "[check] This container's public key (must be on the server):"
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echo "[check] PublicKey = $(wg show "$INTERFACE" public-key 2>/dev/null || echo 'unknown')"
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echo "[check] AllowedIPs = ${VPN_ADDRESS}"
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echo "[check] Verify on server: wg show"
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fi
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# 2. Check whether traffic actually flows through the tunnel
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echo "[check] Testing traffic through tunnel (http://${CHECK_HOST})..."
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local rx_before
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rx_before=$(wg show "$INTERFACE" transfer 2>/dev/null | awk '{print $2}' | head -1)
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if curl -sf --max-time 8 "http://${CHECK_HOST}" > /dev/null 2>&1; then
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echo "[check] OK Traffic flows — tunnel is fully working"
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else
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local rx_after
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rx_after=$(wg show "$INTERFACE" transfer 2>/dev/null | awk '{print $2}' | head -1)
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echo "[check] FAIL http://${CHECK_HOST} unreachable through tunnel"
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if [ -n "$rx_before" ] && [ -n "$rx_after" ]; then
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if [ "$rx_after" -le "$rx_before" ]; then
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echo "[check] RX bytes unchanged (${rx_before} → ${rx_after})"
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echo "[check] Server receives packets but does NOT route them back"
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echo "[check] Fix on VPN server (${VPN_ENDPOINT}):"
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echo "[check] sysctl net.ipv4.ip_forward # must output 1"
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echo "[check] iptables -t nat -L POSTROUTING -v -n # must have MASQUERADE"
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echo "[check] wg show # check peer + AllowedIPs"
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else
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echo "[check] RX increased (${rx_before} → ${rx_after}) — tunnel passes data"
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echo "[check] Issue may be specific to ${CHECK_HOST} or DNS"
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fi
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fi
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local transfer
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transfer=$(wg show "$INTERFACE" transfer 2>/dev/null | awk '{printf "rx=%s tx=%s", $2, $3}')
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echo "[check] wg transfer: ${transfer}"
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fi
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# 3. DNS check
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echo "[check] Testing DNS resolution..."
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if nslookup 1.1.1.1 > /dev/null 2>&1 || nslookup google.com > /dev/null 2>&1; then
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echo "[check] OK DNS resolves"
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else
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echo "[check] FAIL DNS resolution failed"
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echo "[check] resolv.conf: $(tr '\n' ' ' < /etc/resolv.conf)"
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echo "[check] Check that DNS servers are reachable through wg0"
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fi
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echo "[check] ── End of checks ──"
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}
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# ── Main ──
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enable_forwarding
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setup_killswitch
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start_vpn
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check_vpn_connectivity
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health_loop
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