BUG 1340528

- For ICMP error packets, the flow key has to be the same as that of the
original payload. This is because, in a floating IP case, default security
group rules allow only outgoing packets originated by the VM and incoming
packets to VM that belong to the same security group. Packets originated
from the destination floating ip network does not belong to the same security
group and hence will be dropped if we use the outer IP header for forming the
flow key.

Another issue is with the NAT-ing. The ip header source ip and destination ip
+ transport header ports in the icmp error payload have to be NAT-ed back.

Change-Id: If5082cc5fb9d20175a71abac42d09ac27100bf55
BUG 1341529

- if the packet from a resident VM has to go out on physical interface
and if vrouter needs to fragment the packet post tunnel header updation,
fragment only if DF bit is net set. Else, trap the packet to agent for
ICMP error reports

Change-Id: I1d7af762d1b3e095701e24f78737c31bcb9989cc
Merge "BUG 1341529"