documented the new PLUTO environment variables available in the updown script

src/_updown/_updown.in

@@ -118,6 +118,16 @@
 #       PLUTO_XAUTH_ID
 #              is an optional user ID employed by the XAUTH protocol
 #
+#       PLUTO_MARK_IN
+#              is an optional XFRM mark set on the inbound IPsec SA
+#
+#       PLUTO_MARK_OUT
+#              is an optional XFRM mark set on the outbound IPsec SA
+#
+#       PLUTO_ESP_ENC
+#              contains the remote UDP port in the case of ESP_IN_UDP
+#              encapsulation
+#
 
 # define a minimum PATH environment in case it is not set
 PATH="/sbin:/bin:/usr/sbin:/usr/bin:@sbindir@"

src/_updown_espmark/_updown_espmark

@@ -117,6 +117,17 @@
 #
 #       PLUTO_XAUTH_ID
 #              is an optional user ID employed by the XAUTH protocol
+#
+#       PLUTO_MARK_IN
+#              is an optional XFRM mark set on the inbound IPsec SA
+#
+#       PLUTO_MARK_OUT
+#              is an optional XFRM mark set on the outbound IPsec SA
+#
+#       PLUTO_ESP_ENC
+#              contains the remote UDP port in the case of ESP_IN_UDP
+#              encapsulation
+#
 
 # logging of VPN connections
 #