Introduced in Linux 4.11 as BPF_MAP_TYPE_LPM_TRIE.
LPM stands for "Longest Prefix Match".
A Trie is a kind of data structure, also known as a prefix tree.
Intended to efficiently match IP addresses to a stored set of prefixes.
Designed specifically for the CIDR membership use-case.
Example: If you put in 10.0.0.0/8 and 10.40.22.0/24, searching for 10.40.22.12 would return 10.40.22.0/24 because it's the "longest prefix" (the most specific one), even though it technically matches both.