`Transport::listen_on` is an asynchronous operation. It returns immediately but the actual process of establishing a listening socket happens as part of `Transport::poll` which will return one or more `TransportEvent`s related to a particular `listen_on` call.
Currently, `listen_on` returns a `ListenerId` which allows the user of the `Transport` interface to correlate the events with a particular `listen_on` call. This "user" is the `Swarm` runtime. Currently, a user of libp2p establishes a new listening socket by talking to the `Swarm::listen_on` interface and it is not possible to do the same thing via the `NetworkBehaviour` trait.
Within the `NetworkBehaviour` trait, we emit _commands_ to the `Swarm` like `ToSwarm::Dial`. These commands don't have a "return value" like a synchronous function does and thus, if we were to add a `ToSwarm::ListenOn` command, it could not receive the `ListenerId` from the `Transport`.
To fix this and to be consistent with our [coding guidelines](https://github.com/libp2p/rust-libp2p/blob/master/docs/coding-guidelines.md#allow-correlating-asynchronous-responses-to-their-requests) we change the interface of `Transport::listen_on` to require the user to pass in a `ListenerId`. This will allow us to construct a command in a `NetworkBehaviour` that remembers this ID which enables precise tracking of which events containing a `ListenerId` correlate which a particular `listen_on` command.
This is especially important in the context of listening on wildcard addresses like `0.0.0.0` because we end up binding to multiple network interfaces and thus emit multiple events for a single `listen_on` call.
Pull-Request: #3567.
This patch tackles two things at once that are fairly intertwined:
1. There is no such thing as a "substream" in libp2p, the spec and other implementations only talk about "streams". We fix this by deprecating `NegotiatedSubstream`.
2. Previously, `NegotiatedSubstream` was a type alias that pointed to a type from `multistream-select`, effectively leaking the version of `multistream-select` to all dependencies of `libp2p-swarm`. We fix this by introducing a `Stream` newtype.
Resolves: #3759.
Related: #3748.
Pull-Request: #3912.
A `ConnectionHandler` is bound to a single peer. There is no need to embed the `PeerId` in the event that we report to the behaviour, it already knows which peer the event relates to.
Pull-Request: #3895.
This patch removes the 3 out of 4 deprecated public modules. I've left `store` for now because we made some mistakes in declaring that. The items within `store` still need to be publicly visible but I haven't yet figured out a good way of exporting / naming them. Thus, I've left that to a follow-up PR.
Related: #3647.
Pull-Request: #3896.
With this patch, implementations of `ConnectionHandler` (which are typically composed in a tree) can exchange information about the supported protocols of a remote with each other via `ConnectionHandlerEvent::ReportRemoteProtocols`. The provided `ProtocolSupport` enum can describe either additions or removals of the remote peer's protocols.
This information is aggregated in the connection and passed down to the `ConnectionHandler` via `ConnectionEvent::RemoteProtocolsChange`.
Similarly, if the listen protocols of a connection change, all `ConnectionHandler`s on the connection will be notified via `ConnectionEvent::LocalProtocolsChange`. This will allow us to eventually remove `PollParameters` from `NetworkBehaviour`.
This pattern allows protocols on a connection to communicate with each other. For example, protocols like identify can share the list of (supposedly) supported protocols by the remote with all other handlers. A protocol like kademlia can accurately add and remove a remote from its routing table as a result.
Resolves: #2680.
Related: #3124.
Pull-Request: #3651.
Users are encouraged to use `libp2p::connection_limit::Behaviour` which is a one-to-one replacement for this functionality but built as a `NetworkBehaviour`.
Related: #3647.
Pull-Request: #3885.
Currently, the `connection_keep_alive` function of identify does not compute anything but its return value is set through the handler state machine. This is hard to understand and causes surprising behaviour because at the moment, we set `KeepAlive::No` as soon as the remote has answered our identify request. Depending on what else is happening on the connection, this might close the connection before we have successfully answered the remote's identify request.
To fix this, we now compute `connection_keep_alive` based on whether we are still using the connection.
Related: #3844.
Pull-Request: #3876.
The currently provided `ConnectionHandlerUpgrErr` is very hard to use. Not only does it have a long name, it also features 3 levels of nesting which results in a lot of boilerplate. Last but not least, it exposes `multistream-select` as a dependency to all protocols.
We fix all of the above by renaming the type to `StreamUpgradeError` and flattening out its interface. Unrecoverable errors during protocol selection are hidden within the `Io` variant.
Related: #3759.
Pull-Request: #3882.
This removes the deprecated `IntoConnectionHandler` trait and all its implementations. Consequently, `NetworkBehaviour::new_handler` and `NetworkBehaviour::addresses_of_peer` are now gone and the two `handle_` functions are now required to implement.
Related: #3647.
Pull-Request: #3884.
This patch removes all deprecated legacy code from `libp2p-noise` and attempts to collapse all the abstraction layers into something a lot simpler.
Pull-Request: #3511.
When an inbound stream upgrade fails, there isn't a whole lot we can do about that in the handler. In fact, for several errors, we wouldn't even know which specific handler to target, for example, `NegotiationFailed`. Similiarly, in case of an IO error during the upgrade, we don't know which handler the stream was eventually meant to be for.
Pull-Request: #3605.
This patch refactors the identify tests to use `libp2p-swarm-test`. This allows us to delete quite a bit of code and makes several dev-dependencies obsolete.
The `correct_transfer` test is made obsolete by more precise assertions in the `periodic_identify` test. This allows us to remove the dependency on the `upgrade::{apply_inbound,apply_outbound}` functions.
Finally, we also fix a bug where the reported listen addresses to the other node could contain duplicates.
Related: #3748.
Pull-Request: #3851.
Previously, a protocol could be any sequence of bytes as long as it started with `/`. Now, we directly parse a protocol as `String` which enforces it to be valid UTF8.
To notify users of this change, we delete the `ProtocolName` trait. The new requirement is that users need to provide a type that implements `AsRef<str>`.
We also add a `StreamProtocol` newtype in `libp2p-swarm` which provides an easy way for users to ensure their protocol strings are compliant. The newtype enforces that protocol strings start with `/`. `StreamProtocol` also implements `AsRef<str>`, meaning users can directly use it in their upgrades.
`multistream-select` by itself only changes marginally with this patch. The only thing we enforce in the type-system is that protocols must implement `AsRef<str>`.
Resolves: #2831.
Pull-Request: #3746.
Previously, and for unknown legacy reasons, we waited for a configurable delay (default 500ms) upon new connections before we ran the identify protocol. This unnecessarily slows down applications that wait for the identify handshake to complete before performing further actions.
Resolves#3485.
Pull-Request: #3545.
Relayed connections to other peers are created from streams to the relay itself. Internally, such a connection has different states. These however are not relevant to the user and should be encapsulated to allow for more backwards-compatible changes. The only interface exposed is `AsyncRead` and `AsyncWrite`.
Resolves: #3255.
Pull-Request: #3829.
In previous PR #3606 we've made `mdns::Event` `Clone`, but cloning single-use iterators doesn't sound right. Also you have to create an iterator from the actual data returned before putting it into events. So in this PR the iterators are replaced by `Vec`, as it's the type the data originally come from.
Related #3612.
Pull-Request: #3621.
Previously, we would specify the version and path of our workspace dependencies in each of our crates. This is error prone as https://github.com/libp2p/rust-libp2p/pull/3658#discussion_r1153278072 for example shows. Problems like these happened in the past too.
There is no need for us to ever depend on a earlier version than the most current one in our crates. It thus makes sense that we manage this version in a single place.
Cargo supports a feature called "workspace inheritance" which allows us to share a dependency declaration across a workspace and inherit it with `{ workspace = true }`.
We do this for all our workspace dependencies and for the MSRV.
Resolves#3787.
Pull-Request: #3715.
Previously, we would implicitly establish a connection when the user wanted to push identify information to a peer. I believe that this is the wrong behaviour. Instead, I am suggesting to log a message that we are skipping the push to this peer.
Additionally, the way this is currently implemented does not make much sense. Dialing a peer takes time. In case we don't have a connection at all, it could be that we drop the push requests because there isn't an active handler and thus we would have unnecessarily established the connection.
Instead of fixing this - which would require buffering the push messages - I think we should just remove the implicit dial.
Pull-Request: #3843.
In the libp2p specs, the only handshake pattern that is specified is the XX handshake. Support for other handshake patterns can be added through external modules. While we are at it, we rename the remaining types to following the laid out naming convention.
The tests for handshakes other than XX are removed. The handshakes still work as we don't touch them in this patch.
Related #2217.
Pull-Request: #3768.
Previously, we only honored the `support_floodsub` setting when the user did not specify a custom protocol for gossipsub. This patch fixes this and allows users to advertise floodsub even when they use a custom protocol.
Pull-Request: #3837.
- Move helpers to the bottom
- Restructure tests to follow arrange-act-assert
- Only set necessary options on builder for each test
Pull-Request: #3836.
The `unreachable_pub` lint makes us aware of uses of `pub` that are not actually reachable from the crate root. This is considered good because it means reading a `pub` somewhere means it is actually public API. Some of our crates are quite large and keeping their entire API surface in your head is difficult.
We should strive for most items being `pub(crate)`. This lint helps us enforce that.
Pull-Request: #3735.
Previous to this change if the ConnectionHandler::poll for kad was called more frequently than the connection idle timeout the timeout would continually be pushed further into the future. After this change kad now will preserve the existing idle deadline.
Pull-Request: #3801.
Previously, we closed the entire connection upon receiving too many upgrade errors. This is unnecessarily aggressive. For example, an upgrade error may be caused by the remote dropping a stream during the initial handshake which is completely isolated from other protocols running on the same connection.
Instead of closing the connection, set `KeepAlive::No`.
Related: #3591.
Resolves: #3690.
Pull-Request: #3625.
This PR renames some method names that don't follow Rust naming conventions or behave differently from what the name suggests:
- Enforce "try" prefix on all methods that return `Result`.
- Enforce "encode" method name for methods that return encoded bytes.
- Enforce "to_bytes" method name for methods that return raw bytes.
- Enforce "decode" method name for methods that convert encoded key.
- Enforce "from_bytes" method name for methods that convert raw bytes.
Pull-Request: #3775.
With the changes from #3767, we made the `connect` test flaky because the `Swarm` was fully passed to the future and thus dropped as soon as the connection was established. We pass a mutable reference instead which keeps the `Swarm` alive.
Pull-Request: #3780.
Previously, the relay server would erroneously send its own `PeerId` in the STOP message to the client upon an incoming relay connection. This is obviously wrong and results in failed connection upgrades in other implementations.
Pull-Request: #3767.
