From 274902612c23d6a4dad21b78b394f568ab0e6b1a Mon Sep 17 00:00:00 2001
From: first <first@noreply.git.r21.io>
Date: Sun, 6 Jul 2025 07:37:24 +0000
Subject: [PATCH] Add synterloper/setup_synterloper.sh

---
 synterloper/setup_synterloper.sh | 122 +++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 synterloper/setup_synterloper.sh

diff --git a/synterloper/setup_synterloper.sh b/synterloper/setup_synterloper.sh
new file mode 100644
index 0000000..14be435
--- /dev/null
+++ b/synterloper/setup_synterloper.sh
@@ -0,0 +1,122 @@
+#!/bin/sh
+#
+# setup_synterloper.sh
+#
+# Sets up a background packet capture service for a specified TCP port (default 22).
+# Designed for automated execution on first-boot via cloud-init or user data.
+#
+
+# --- Configuration ---
+LOG_DIR="/var/log/synterloper"
+CAPTURE_PORT="22"
+ROTATE_SECONDS="3600" # 3600 seconds = 1 hour
+RETENTION_DAYS="7"
+SNAP_LEN="128" # Bytes to capture per packet
+
+# --- Script Logic ---
+
+# Ensure script is run as root
+if [ "$(id -u)" -ne 0 ]; then
+  echo "Error: This script must be run as root." >&2
+  exit 1
+fi
+
+# Detect OS and install dependencies
+OS_TYPE=$(uname)
+echo "Initializing SYNterloper setup for OS: ${OS_TYPE}"
+
+if [ "${OS_TYPE}" = "Linux" ]; then
+  echo "Installing dependencies (tcpdump) using apt..."
+  export DEBIAN_FRONTEND=noninteractive
+  if ! apt-get update >/dev/null; then echo "Error: apt-get update failed."; exit 1; fi
+  if ! apt-get install -y tcpdump >/dev/null; then echo "Error: apt-get install failed."; exit 1; fi
+elif [ "${OS_TYPE}" = "FreeBSD" ]; then
+  echo "Installing dependencies (tcpdump) using pkg..."
+  if ! pkg install -y tcpdump >/dev/null; then echo "Error: pkg install failed."; exit 1; fi
+else
+  echo "Error: Unsupported OS type '${OS_TYPE}'" >&2
+  exit 1
+fi
+echo "Dependency installation complete."
+
+# Create log directory with appropriate permissions
+echo "Creating log directory: ${LOG_DIR}"
+mkdir -p "${LOG_DIR}"
+chown root:root "${LOG_DIR}"
+chmod 700 "${LOG_DIR}"
+
+# Create the system service
+if [ "${OS_TYPE}" = "Linux" ]; then
+  # Systemd Service for Linux (Debian/Ubuntu)
+  echo "Creating systemd service: synterloper.service"
+  cat > /etc/systemd/system/synterloper.service <<EOF
+[Unit]
+Description=SYNterloper - TCP Port Connection Logger
+After=network.target
+
+[Service]
+Type=simple
+ExecStart=/bin/sh -c 'exec /usr/sbin/tcpdump -i \$(ip -4 route get 1.1.1.1 | grep -oP "dev \\K\\S+") -s ${SNAP_LEN} -w ${LOG_DIR}/capture-%Y-%m-%d_%H-%M.pcap -G ${ROTATE_SECONDS} "tcp port ${CAPTURE_PORT}"'
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
+EOF
+
+  echo "Enabling and starting synterloper service (systemd)..."
+  systemctl daemon-reload
+  systemctl enable synterloper.service
+  systemctl start synterloper.service
+
+elif [ "${OS_TYPE}" = "FreeBSD" ]; then
+  # rc.d Service for FreeBSD
+  echo "Creating rc.d script: /usr/local/etc/rc.d/synterloper"
+  cat > /usr/local/etc/rc.d/synterloper <<'EOF'
+#!/bin/sh
+#
+# PROVIDE: synterloper
+# REQUIRE: NETWORKING
+# KEYWORD: shutdown
+#
+. /etc/rc.subr
+name="synterloper"
+rcvar="synterloper_enable"
+load_rc_config \$name
+: \${synterloper_enable:="NO"}
+: \${synterloper_port:="22"}
+: \${synterloper_logdir:="/var/log/synterloper"}
+: \${synterloper_rotate_sec:="3600"}
+: \${synterloper_snaplen:="128"}
+default_iface=\$(route -n get default | grep 'interface:' | awk '{print \$2}')
+command="/usr/sbin/tcpdump"
+command_args="-i \${default_iface} -s \${synterloper_snaplen} -w \${synterloper_logdir}/capture-%Y-%m-%d_%H-%M.pcap -G \${synterloper_rotate_sec} \"tcp port \${synterloper_port}\""
+pidfile="/var/run/\${name}.pid"
+start_cmd="daemon -p \${pidfile} \${command} \${command_args}"
+run_rc_command "\$1"
+EOF
+  chmod +x /usr/local/etc/rc.d/synterloper
+
+  echo "Enabling and starting synterloper service (rc.d)..."
+  sysrc synterloper_enable=YES
+  sysrc synterloper_port="${CAPTURE_PORT}"
+  sysrc synterloper_logdir="${LOG_DIR}"
+  sysrc synterloper_rotate_sec="${ROTATE_SECONDS}"
+  sysrc synterloper_snaplen="${SNAP_LEN}"
+  service synterloper start
+fi
+echo "Service configuration complete."
+
+# Create the log rotation cron job
+echo "Creating daily log cleanup cron job..."
+cat > /etc/cron.daily/synterloper-cleanup <<EOF
+#!/bin/sh
+# Deletes SYNterloper capture files older than ${RETENTION_DAYS} days.
+find "${LOG_DIR}" -name "*.pcap" -type f -mtime +${RETENTION_DAYS} -delete
+EOF
+chmod +x /etc/cron.daily/synterloper-cleanup
+
+echo ""
+echo "--- SYNterloper Setup Complete ---"
+echo "Service is now logging TCP port ${CAPTURE_PORT} to ${LOG_DIR}"
+echo "----------------------------------"
\ No newline at end of file