Windows has the "RtmGetMostSpecificDestination" call: https://docs.microsoft.com/en-us/windows/win32/rras/search-for-the-best-route
In particular, I wanted to search for the best route, AND pick up the PMTU from that (if it existed) for older UDP applications like dnssec[1] and newer ones like QUIC[2]. The alternatives, which basically include probing perpetually and/or picking really low values, seem increasingly less than optimal. Put in a wrapper around bpf[3]'s lpm calls? Create a new netlink message? [1] https://github.com/dns-violations/dnsflagday/issues/125 [2] https://tools.ietf.org/html/draft-ietf-quic-transport-22#section-14.1 [3] https://github.com/torvalds/linux/blob/master/kernel/bpf/lpm_trie.c#L164 -- Dave Täht CTO, TekLibre, LLC http://www.teklibre.com Tel: 1-831-205-9740
