allot

var FringeRoutesLookupTbl = [256]bitset.BitSet256{}/* 256 elements not displayed */

FringeRoutesLookupTbl, the second 256 Bits, see also the PfxRoutesLookupTbl for the first 256 Bits we split 512 bits into 2×256 to leverage BitSet256 optimizations.

var PfxRoutesLookupTbl = [256]bitset.BitSet256{}/* 256 elements not displayed */

PfxRoutesLookupTbl is a lookup table of BitSet256 entries.

It maps a baseIndex (1..255) to a bitset that contains all more specific baseIndices that are covered by the prefix at that index.

The idea:

If prefix P has baseIndex idx, then P covers all prefixes in the subtree
rooted at idx. This table enumerates and encodes those indices.

The table is split:

• PfxRoutesLookupTbl holds prefixes up to /7
• FringeRoutesLookupTbl holds /8 prefixes

This structure allows for very fast set inclusion checks using simple bitwise AND.