kern/185876: ipfw not matching incoming packets decapsulating ipsec. example l2tp/ipsec

[Georgios Amanakis]

The following patch resolves it (it has to be tested thoroughly).

Index: netipsec/xform_ipip.c
===================================================================
--- netipsec/xform_ipip.c       (revision 262492)
+++ netipsec/xform_ipip.c       (working copy)
@@ -181,6 +181,7 @@
        IPIPSTAT_INC(ipips_ipackets);

        m_copydata(m, 0, 1, &v);
+       m_clrprotoflags(m);

        switch (v >> 4) {
 #ifdef INET