Base 32 encoded bolt 11 invoices only allow 10 bits to express the
length of the feature vector in a tagged field, so there is a much
lower limit on the values invoice custom features can hold.
Other places in the protocol are theoretically limited by the maximum
message size, but since we express a feature bit as u16 we don't need
to be concerned about this.
The decision is made to track maximum per-set in the feature manager,
which is conceptually aware of sets and then validate in lnwire/features
against some arbitrary maximum value provided to the caller to keep
the base features package unaware of sets.
In this commit, we add a new RequiresFeature method to the feature
vector struct. This method allows us to check if the set of features
we're examining *require* that the even portion of a bit pair be set.
This can be used to check if new behavior should be allowed (after we
flip new bits to be required) for existing contexts.
The number and the name will be separate on the rpc level, so we remove
the feature bit from the string. Currently this method is unused apart
from maybe in some rare logging instances.
This is a rewrite of feature vectors in lnwire. This has a few
benefits:
1) a simpler interface
2) separate structs for a plain set of feature bits and a feature
vector with associated feature names
their respective feature sets
3) loosened requirements that bits MUST be assigned in pairs
4) fix endianness of encoding/decoding
This commit does away with all the old manual message equality tests
and replace it with a single property-based test that uses the
testing/quick package. This test uses a single scenario which MUST hold
for all the messages type and all possible messages generated for those
types. As a result we are able to do away with all the prior manually
generated test data as the fuzzer to scan the input space looking for a
message that violates the scenario.
'init' message is the first message reveals the features supported or required
by this node. Nodes wait for receipt of the other's features to simplify error
diagnosis where features are incompatible. This message will help negotioate the
the features which are supported by both sides.
