Nmap's changes have been moved from the NMAP_MODIFICATIONS file to the
Github repo at https://github.com/nmap/libdnet
The NMAP_MODIFICATIONS file instead will document only the changes made
to strip unused parts of the libdnet source prior to inclusion in Nmap.
set correctly.
1. Shift the low-order bits of fc by 20 bits, not 28, because fl is a
20-bit field.
2. Use a mask in host byte order to mask fl, which is also provided in
host byte order.
3. Swap | and & in combining fc and fl.
