#2 off-by-one error in data sequencing?

[Jeff McAdams]

There is possibly an off-by-one error in updating
sequence numbers on the data channel when a packet is
dropped. When a data channel sequencing is in use, and
a packet is dropped, the next packet arrives with a
higher sequence number than l2tpd was expecting...there
is code to update the next sequence number expected to
the new value, but I believe the code sets the next
sequence number to be expected to be one less than what
it should be...meaning that the next data packet that
comes in still has a sequence number ahead of the
sequence number that is expected by l2tpd.

This needs to be checked for sure as I'm not sure that
this is what's occuring.