Add an rc.d script to setup a netflow export via ng_netflow

The default is to export netflow data on localhost on the netflow port.
ngtee is used to have the lowest overhead possible.
The ipfw ng hook is the netflow port (it can only be numeric)
Default is netflow version 5.

Sponsored-By:   Gandi.net
Reviewed by:	bapt (earlier version), olivier (earlier version)

etc/rc.d/ipfw_netflow

@@ -0,0 +1,77 @@
+#!/bin/sh
+#
+# $FreeBSD$
+#
+
+# PROVIDE: ipfw_netflow
+# REQUIRE: ipfw
+# KEYWORD: nojailvnet
+
+. /etc/rc.subr
+. /etc/network.subr
+
+name="ipfw_netflow"
+desc="firewall, ipfw, netflow"
+rcvar="${name}_enable"
+start_cmd="${name}_start"
+stop_cmd="${name}_stop"
+start_precmd="${name}_test"
+status_cmd="${name}_status"
+required_modules="ipfw ng_netflow ng_ipfw"
+extra_commands="status"
+
+: ${ipfw_netflow_hook:=9995}
+: ${ipfw_netflow_rule:=01000}
+: ${ipfw_netflow_ip:=127.0.0.1}
+: ${ipfw_netflow_port:=9995}
+: ${ipfw_netflow_version:=}
+
+ipfw_netflow_test()
+{
+    if [ "${ipfw_netflow_version}" != "" ] && [ "${ipfw_netflow_version}" != 9 ]; then
+	err 1 "Unknown netflow version \'${ipfw_netflow_version}\'"
+    fi
+    case "${ipfw_netflow_hook}" in
+	[!0-9]*)
+	    err 1 "Bad value \"${ipfw_netflow_hook}\": Hook must be numerical"
+    esac
+    case "${ipfw_netflow_rule}" in
+	[!0-9]*)
+	    err 1 "Bad value \"${ipfw_netflow_rule}\": Rule number must be numerical"
+    esac
+}
+
+ipfw_netflow_is_running()
+{
+	ngctl show netflow: > /dev/null 2>&1 && return 0 || return 1
+}
+
+ipfw_netflow_status()
+{
+	ipfw_netflow_is_running && echo "ipfw_netflow is active" || echo "ipfw_netflow is not active"
+}
+
+ipfw_netflow_start()
+{
+	ipfw_netflow_is_running && err 1 "ipfw_netflow is already active"
+	ipfw add ${ipfw_netflow_rule} ngtee ${ipfw_netflow_hook} ip from any to any
+	ngctl -f - <<-EOF
+	mkpeer ipfw: netflow ${ipfw_netflow_hook} iface0
+	name ipfw:${ipfw_netflow_hook} netflow
+	mkpeer netflow: ksocket export${ipfw_netflow_version} inet/dgram/udp
+	msg netflow: setdlt {iface=0 dlt=12}
+	name netflow:export${ipfw_netflow_version} netflow_export
+	msg netflow:export${ipfw_netflow_version} connect inet/${ipfw_netflow_ip}:${ipfw_netflow_port}
+EOF
+}
+
+ipfw_netflow_stop()
+{
+    ipfw_netflow_is_running || err 1 "ipfw_netflow is not active"
+    ngctl shutdown netflow:
+    ipfw delete ${ipfw_netflow_rule}
+}
+
+load_rc_config $name
+
+run_rc_command $*