A `ProtocolsHandler`, now `ConnectionHandler`, handels a connection, not
a protocol. Thus the name `CONNECTIONHandler` is more appropriate.
Next to the rename of `ProtocolsHandler` this commit renames the `mod
protocols_handler` to `mod handler`. Finally all combinators (e.g.
`ProtocolsHandlerSelect`) are renamed appropriately.
Allows `NetworkBehaviour` implementations to dial a peer, but instruct
the dialed connection to be upgraded as if it were the listening
endpoint.
This is needed when establishing direct connections through NATs and/or
Firewalls (hole punching). When hole punching via TCP (QUIC is different
but similar) both ends dial the other at the same time resulting in a
simultaneously opened TCP connection. To disambiguate who is the dialer
and who the listener there are two options:
1. Use the Simultaneous Open Extension of Multistream Select. See
[sim-open] specification and [sim-open-rust] Rust implementation.
2. Disambiguate the role (dialer or listener) based on the role within
the DCUtR [dcutr] protocol. More specifically the node initiating the
DCUtR process will act as a listener and the other as a dialer.
This commit enables (2), i.e. enables the DCUtR protocol to specify the
role used once the connection is established.
While on the positive side (2) requires one round trip less than (1), on
the negative side (2) only works for coordinated simultaneous dials.
I.e. when a simultaneous dial happens by chance, and not coordinated via
DCUtR, the connection attempt fails when only (2) is in place.
[sim-open]: https://github.com/libp2p/specs/blob/master/connections/simopen.md
[sim-open-rust]: https://github.com/libp2p/rust-libp2p/pull/2066
[dcutr]: https://github.com/libp2p/specs/blob/master/relay/DCUtR.md
This commit adds a behaviour protocol that implements the AutoNAT specification.
It enables users to detect whether they are behind a NAT. The Autonat Protocol
implements a Codec for the Request-Response protocol, and wraps it in a new
Network Behaviour with some additional functionality.
Co-authored-by: David Craven <david@craven.ch>
Co-authored-by: Max Inden <mail@max-inden.de>
