pcap_lookupnet(3) on FreeBSD
The text d07018edb9ff, as FreeBSD 13.4-RELEASE, FreeBSD 13.3-RELEASE, FreeBSD 13.2-RELEASE, FreeBSD 13.1-RELEASE, FreeBSD 13.0-RELEASE, FreeBSD 12.4-RELEASE, FreeBSD 12.3-RELEASE, FreeBSD 12.2-RELEASE, FreeBSD 11.4-RELEASE shipped it.
find the IPv4 network number and netmask for a device