cgnat: T9473: reject external addresses used in more than one range

Ports are allocated per external range, starting over for each one. An
address listed in two ranges of one pool, or in the pools of two rules
with overlapping port ranges, was therefore handed out twice: two
subscribers got the same external address and port block. The capacity
check also counted such an address twice.

Such overlaps are now rejected. Pools of different rules may still share
an address when their port ranges are distinct.

0 files changed, 0 insertions, 0 deletions