These are more convenient and safer than the manual vtables we have in
the fuzzer support code. We can override individual member functions,
and C++ will take care of correctly casting and offsetting this-pointers
when needed.
So we don't need to write so many edge case tests ourselves for things
like parsers, which really don't need those manual tests, as long as we
can check for some properties like "can output the parsed data and it'll
be the same as the input".
Instead of using `target_link_modules`, which does magic that we no
longer need, because we only have 1 library we install, and all binaries
we build link statically because they need access to internal symbols.
We now depend on libsodium unconditionally. Future work will require
functions from libsodium, and nobody we're aware of uses the nacl build
for anything other than making sure it still works on CI.
Also flip some callback asserts, because they can be reached by fuzzing
eventually.
Also update the bootstrapd checksum, since the alpine image changed a
bit.
If the `recvbuf` network function returns 0 all the time, that means
there is never any data available on the TCP socket. This change makes
it so there is a random amount of data available on the TCP socket.
This invalidates the bootstrap fuzzer corpus.
It can't happen in almost every reality, except when the RNG is fairly
broken and doesn't add 2 fake DHT friends on startup. Still, this code
should be defensive and never index outside `num_friends` elements.
Ideally this would be able to reach some of the events, so we can write
code to respond to those events, but so far only the friend request
event actually happens.
This is the "server-side" part of the new friend finding system,
allowing DHT nodes to store small amounts of data and permit searching
for it. A forwarding (proxying) mechanism allows this to be used by TCP
clients, and deals with non-transitivity in the network.
These help creating fuzzer fixtures with non-trivially constructed
objects and takes care of cleaning them up afterwards so the fuzzer code
can focus on the system under test.
The idea here is to have a `Network` object that contains functions for
network operations and an optional userdata object that can manage those
network operations. This allows e.g. a fuzzer to replace the network
functions with no-ops or fuzzer inputs, reducing the need for `#ifdef`s.
