Gateway_less_Fwd: vrouter crash observed @boost::asio::ip::address::is_v4, FlowEntry::GetUcRoute, FlowEntry::GetSourceRouteInfo while pinging IPv6 addresses when IP Fabric VN is configured

vrouter crash observed @boost::asio::ip::address::is_v4, FlowEntry::GetUcRoute, FlowEntry::GetSourceRouteInfo while pinging IPv6 addresses when IP Fabric VN is configured.

Steps
-----
1. Configure a VN (subnets from both IPv4 and IPv6) and configure IP Fabric VN as provider network
2. Launch 2 VMs with dual stack on 2 computes
3. Try pinging IPV6 addresses from each other VM. This step causes agent crash.

Core was generated by `/usr/bin/contrail-vrouter-agent'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x000000000186f97e in boost::asio::ip::address::is_v4 (this=0xd8) at /usr/include/boost/asio/ip/address.hpp:82
82 /usr/include/boost/asio/ip/address.hpp: No such file or directory.
(gdb) bt
#0 0x000000000186f97e in boost::asio::ip::address::is_v4 (this=0xd8) at /usr/include/boost/asio/ip/address.hpp:82
#1 0x0000000001fc1551 in FlowEntry::GetUcRoute (entry=0x7f84d4050f90, addr=...)
    at controller/src/vnsw/agent/pkt/flow_entry.cc:848
#2 0x0000000001fc2eef in FlowEntry::GetSourceRouteInfo (this=0x7f84e72b5e20, rt=0x0)
    at controller/src/vnsw/agent/pkt/flow_entry.cc:1345
#3 0x0000000001fc0b9d in FlowEntry::InitFwdFlow (this=0x7f84e72b5e20, info=0x7f84faf32690, pkt=0x7f84dc01f110,
    ctrl=0x7f84faf32610, rev_ctrl=0x7f84faf32650, rflow=0x7f84e72b6460, agent=0x53b8a10)
    at controller/src/vnsw/agent/pkt/flow_entry.cc:691
#4 0x00000000020252a4 in PktFlowInfo::Add (this=0x7f84faf32690, pkt=0x7f84dc01f110, in=0x7f84faf32610,
    out=0x7f84faf32650) at controller/src/vnsw/agent/pkt/pkt_flow_info.cc:1878
#5 0x000000000203fc03 in FlowHandler::Run (this=0x7f84f0026a80)
    at controller/src/vnsw/agent/pkt/flow_handler.cc:163
#6 0x0000000002035079 in Proto::RunProtoHandler (this=0x7f84e4c90130, handler=0x7f84f0026a80)
    at controller/src/vnsw/agent/pkt/proto.cc:51
#7 0x0000000002035166 in Proto::ProcessProto (this=0x7f84e4c90130, msg_info=...)
    at controller/src/vnsw/agent/pkt/proto.cc:66
#8 0x000000000200631e in FlowProto::FlowEventHandler (this=0x7f84e4c90130, req=0x7f84dc01f270, table=
    0x7f84e72b4680) at controller/src/vnsw/agent/pkt/flow_proto.cc:400
#9 0x000000000203b1ca in FlowEventQueue::HandleEvent (this=0x7f84d98db720, event=0x7f84dc01f270)
    at controller/src/vnsw/agent/pkt/flow_event.cc:250
#10 0x000000000203a56c in FlowEventQueueBase::Handler (this=0x7f84d98db720, event=0x7f84dc01f270)
    at controller/src/vnsw/agent/pkt/flow_event.cc:105
#11 0x000000000203df04 in boost::_mfi::mf1<bool, FlowEventQueueBase, FlowEvent*>::operator() (this=0x7f84faf32b18,
    p=0x7f84d98db720, a1=0x7f84dc01f270) at /usr/include/boost/bind/mem_fn_template.hpp:165
#12 0x000000000203d8fa in boost::_bi::list2<boost::_bi::value<FlowEventQueueBase*>, boost::arg<1> >::operator()<bool, boost::_mfi::mf1<bool, FlowEventQueueBase, FlowEvent*>, boost::_bi::list1<FlowEvent*&> > (this=0x7f84faf32b28,
    f=..., a=...) at /usr/include/boost/bind/bind.hpp:303
#13 0x000000000203d336 in boost::_bi::bind_t<bool, boost::_mfi::mf1<bool, FlowEventQueueBase, FlowEvent*>, boost::_bi::list2<boost::_bi::value<FlowEventQueueBase*>, boost::arg<1> > >::operator()<FlowEvent*> (this=0x7f84faf32b18,
    a1=@0x7f84faf32a70: 0x7f84dc01f270) at /usr/include/boost/bind/bind_template.hpp:32
#14 0x000000000203cfeb in boost::detail::function::function_obj_invoker1<boost::_bi::bind_t<bool, boost::_mfi::mf1<bool, FlowEventQueueBase, FlowEvent*>, boost::_bi::list2<boost::_bi::value<FlowEventQueueBase*>, boost::arg<1> > >, bool, FlowEvent*>::invoke (function_obj_ptr=..., a0=0x7f84dc01f270)
    at /usr/include/boost/function/function_template.hpp:132
#15 0x000000000200f4e5 in boost::function1<bool, FlowEvent*>::operator() (this=0x7f84faf32b10, a0=0x7f84dc01f270)
    at /usr/include/boost/function/function_template.hpp:767
#16 0x000000000200f1a9 in QueueTaskRunner<FlowEvent*, WorkQueue<FlowEvent*> >::RunQueue (this=0x7f84dc01fc80)
    at controller/src/base/queue_task.h:67
#17 0x000000000200f058 in QueueTaskRunner<FlowEvent*, WorkQueue<FlowEvent*> >::Run (this=0x7f84dc01fc80)
    at controller/src/base/queue_task.h:42
#18 0x00000000029a5a18 in TaskImpl::execute (this=0x7f84fb8dfe40) at controller/src/base/task.cc:277
#19 0x00007f8502ea1b3a in ?? () from /usr/lib/libtbb.so.2
#20 0x00007f8502e9d816 in ?? () from /usr/lib/libtbb.so.2
#21 0x00007f8502e9cf4b in ?? () from /usr/lib/libtbb.so.2
#22 0x00007f8502e990ff in ?? () from /usr/lib/libtbb.so.2
#23 0x00007f8502e992f9 in ?? () from /usr/lib/libtbb.so.2
#24 0x00007f85030bd184 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#25 0x00007f850239637d in clone () from /lib/x86_64-linux-gnu/libc.so.6
(gdb)

root@nodek11:/usr/bin# contrail-version
Package Version Build-ID | Repo | Package Name
-------------------------------------- ------------------------------ ----------------------------------
contrail-lib 5.0.0-72 72
contrail-nodemgr 5.0.0-72 72
contrail-setup 5.0.0-72 72
contrail-utils 5.0.0-72 72
contrail-vrouter-agent 5.0.0-72 72
contrail-vrouter-common 5.0.0-72 72
contrail-vrouter-dkms 5.0.0-72 72
contrail-vrouter-init 5.0.0-72 72
contrail-vrouter-utils 5.0.0-72 72
nova-common 2:13.0.0-0ubuntu2~cloud0.1contrail1 72
nova-compute 2:13.0.0-0ubuntu2~cloud0.1contrail1 72
nova-compute-kvm 2:13.0.0-0ubuntu2~cloud0.1contrail1 72
nova-compute-libvirt 2:13.0.0-0ubuntu2~cloud0.1contrail1 72
python-contrail 5.0.0-72 72
python-contrail-vrouter-api 5.0.0-72 72
python-neutronclient 1:4.1.1-2~cloud0.2contrail 72
python-nova 2:13.0.0-0ubuntu2~cloud0.1contrail1 72
python-opencontrail-vrouter-netns 5.0.0-72 72
root@nodek11:/usr/bin#