We have code in microdescs_parse_from_string() to record the digests
of microdescriptors that we could not parse. But right now, that
code looks at the md->digest field, which is a bit inelegant, and
will stand in the way of sensible refactoring.
Instead, use a local variable to hold the digest.
Previously we had decoded the asn.1 to get a public key, and then
discarded the asn.1 so that we had to re-encode the key to store it
in the onion_pkey field of a microdesc_t or routerinfo_t.
Now we can just do a tor_memdup() instead, which should be loads
faster.
Nick Mathewson
Neel Chauhan
George Kadianakis