For the last [two years](https://github.com/libp2p/rust-libp2p/blob/master/CHANGELOG.md#version-0190-2020-05-18), we have been carrying around a non-compliant implementation of the noise protocol for libp2p. It is time to follow through on the announcement in that changelog entry and deprecate it. Users should use the spec compliant implementation instead.
1. This will reduce the maintenance effort of our codebase.
2. We will improve compile-times because we no longer need to depend on `libsodium` to test cryptography that is only part of the non-compliant implementation.
3. It will simplify usage of `rust-libp2p` because users cannot accidentally choose the wrong implementation.
As I do frequently, I corrected for the latest clippy warnings. This will make sure the CI won't complain in the future. We could automate this btw and maybe run the nightly version of clippy.
In case support for e.g. RSA keys is disabled at compile-time, we will now print a better error message. For example:
> Failed to dial Some(PeerId("QmcZf59bWwK5XFi76CZX8cbJ4BhTzzA3gU1ZjYZcYW3dwt")): Failed to negotiate transport protocol(s): [(/dnsaddr/bootstrap.libp2p.io/p2p/QmcZf59bWwK5XFi76CZX8cbJ4BhTzzA3gU1ZjYZcYW3dwt): : Handshake failed: Handshake failed: Invalid public key: Key decoding error: RSA keys are unsupported)]
Fixes#2971.
Remove the concept of individual `Transport::Listener` streams from `Transport`.
Instead the `Transport` is polled directly via `Transport::poll`. The
`Transport` is now responsible for driving its listeners.
Previously `libp2p-swarm` required a `Transport` to be `Clone`. Methods
on `Transport`, e.g. `Transport::dial` would take ownership, requiring
e.g. a `Clone::clone` before calling `Transport::dial`.
The requirement of `Transport` to be `Clone` is no longer needed in
`libp2p-swarm`. E.g. concurrent dialing can be done without a clone per
dial.
This commit removes the requirement of `Clone` for `Transport` in
`libp2p-swarm`. As a follow-up methods on `Transport` no longer take
ownership, but instead a mutable reference (`&mut self`).
On the one hand this simplifies `libp2p-swarm`, on the other it
simplifies implementations of `Transport`.
Move transport upgrade protocols from `protocols/`
to `transports/`, such that only "application protocols"
that depend on `libp2p-swarm` remain in `protocols/`,
whereas there is no such dependency in `transports/`
outside of integration tests.
Tweak README and top-level CHANGELOG.
