#!/usr/bin/env bash
# Capture UDP/1194 to vpn/tcpdump-openvpn.log (and show live in the terminal).
# Usage: sudo bash vpn/capture-openvpn-udp.sh
#        From repo root: sudo bash vpn/capture-openvpn-udp.sh
#
# Stop with Ctrl+C, then open tcpdump-openvpn.log in your editor.

set -euo pipefail

DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
OUT="$DIR/tcpdump-openvpn.log"

if [[ "$(id -u)" -ne 0 ]]; then
  echo "Run as root: sudo bash $0" >&2
  exit 1
fi

{
  echo "=== OpenVPN UDP/1194 capture — $(date -u +"%Y-%m-%dT%H:%M:%SZ") UTC ==="
  echo "=== Output file: $OUT ==="
  echo "=== Press Ctrl+C to stop. Start your VPN client (Connect) within ~15 seconds. ==="
  echo ""
  tcpdump -n -i any udp port 1194 -l 2>&1
} | tee "$OUT"