[identify] Implement /ipfs/id/push/1.0.0 alongside some refactoring. (#1999)

* Implement /ipfs/id/push/1.0.0 alongside some refactoring.

  * Implement /ipfs/id/push/1.0.0, i.e. the ability to actively
    push information of the local peer to specific remotes.
  * Make the initial delay as well as the recurring delay
    for the periodic identification requests configurable,
    introducing `IdentifyConfig`.

* Fix test.

* Fix example.

* Update protocols/identify/src/identify.rs

Co-authored-by: Max Inden <mail@max-inden.de>

* Update protocols/identify/src/identify.rs

Co-authored-by: Max Inden <mail@max-inden.de>

* Update versions and changelogs.

Co-authored-by: Max Inden <mail@max-inden.de>

CHANGELOG.md

@@ -42,6 +42,10 @@
 
 # `libp2p` facade crate
 
+## Version 0.37.0 [unreleased]
+
+- Update `libp2p-identify`.
+
 ## Version 0.36.0 [2021-03-17]
 
 - Consolidate top-level utility functions for constructing development

Cargo.toml

@@ -2,7 +2,7 @@
 name = "libp2p"
 edition = "2018"
 description = "Peer-to-peer networking library"
-version = "0.36.0"
+version = "0.37.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 license = "MIT"
 repository = "https://github.com/libp2p/rust-libp2p"
@@ -67,7 +67,7 @@ lazy_static = "1.2"
 libp2p-core = { version = "0.28.0", path = "core",  default-features = false }
 libp2p-floodsub = { version = "0.28.0", path = "protocols/floodsub", optional = true }
 libp2p-gossipsub = { version = "0.29.0", path = "./protocols/gossipsub", optional = true }
-libp2p-identify = { version = "0.28.0", path = "protocols/identify", optional = true }
+libp2p-identify = { version = "0.29.0", path = "protocols/identify", optional = true }
 libp2p-kad = { version = "0.29.0", path = "protocols/kad", optional = true }
 libp2p-mplex = { version = "0.28.0", path = "muxers/mplex", optional = true }
 libp2p-noise = { version = "0.30.0", path = "transports/noise", optional = true }

examples/ipfs-private.rs

@@ -38,7 +38,7 @@ use libp2p::{
         either::EitherTransport, muxing::StreamMuxerBox, transport, transport::upgrade::Version,
     },
     gossipsub::{self, Gossipsub, GossipsubConfigBuilder, GossipsubEvent, MessageAuthenticity},
-    identify::{Identify, IdentifyEvent},
+    identify::{Identify, IdentifyConfig, IdentifyEvent},
     identity,
     multiaddr::Protocol,
     noise,
@@ -245,11 +245,10 @@ fn main() -> Result<(), Box<dyn Error>> {
                 gossipsub_config,
             )
             .expect("Valid configuration"),
-            identify: Identify::new(
+            identify: Identify::new(IdentifyConfig::new(
                 "/ipfs/0.1.0".into(),
-                "rust-ipfs-example".into(),
                 local_key.public(),
-            ),
+            )),
             ping: Ping::new(PingConfig::new()),
         };
 

protocols/identify/CHANGELOG.md

@@ -1,3 +1,9 @@
+# 0.29.0 [unreleased]
+
+- Implement the `/ipfs/id/push/1.0.0` protocol.
+  cf. https://github.com/libp2p/specs/tree/master/identify#identifypush
+  [PR 1999](https://github.com/libp2p/rust-libp2p/pull/1999)
+
 # 0.28.0 [2021-03-17]
 
 - Update `libp2p-swarm`.

protocols/identify/Cargo.toml

@@ -2,7 +2,7 @@
 name = "libp2p-identify"
 edition = "2018"
 description = "Nodes identifcation protocol for libp2p"
-version = "0.28.0"
+version = "0.29.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 license = "MIT"
 repository = "https://github.com/libp2p/rust-libp2p"
@@ -20,6 +20,7 @@ wasm-timer = "0.2"
 
 [dev-dependencies]
 async-std = "1.6.2"
+env_logger = "0.8"
 libp2p-mplex = { path = "../../muxers/mplex" }
 libp2p-noise = { path = "../../transports/noise" }
 libp2p-tcp = { path = "../../transports/tcp" }

protocols/identify/src/handler.rs

@@ -18,12 +18,25 @@
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-use crate::protocol::{RemoteInfo, IdentifyProtocolConfig, ReplySubstream};
+use crate::protocol::{
+    IdentifyProtocol,
+    IdentifyPushProtocol,
+    IdentifyInfo,
+    InboundPush,
+    OutboundPush,
+    ReplySubstream
+};
 use futures::prelude::*;
+use libp2p_core::either::{
+    EitherError,
+    EitherOutput,
+};
 use libp2p_core::upgrade::{
+    EitherUpgrade,
     InboundUpgrade,
     OutboundUpgrade,
-    ReadOneError
+    SelectUpgrade,
+    UpgradeError,
 };
 use libp2p_swarm::{
     NegotiatedSubstream,
@@ -34,89 +47,119 @@ use libp2p_swarm::{
     ProtocolsHandlerUpgrErr
 };
 use smallvec::SmallVec;
-use std::{pin::Pin, task::Context, task::Poll, time::Duration};
+use std::{io, pin::Pin, task::Context, task::Poll, time::Duration};
 use wasm_timer::Delay;
 
-/// Delay between the moment we connect and the first time we identify.
-const DELAY_TO_FIRST_ID: Duration = Duration::from_millis(500);
-/// After an identification succeeded, wait this long before the next time.
-const DELAY_TO_NEXT_ID: Duration = Duration::from_secs(5 * 60);
-/// After we failed to identify the remote, try again after the given delay.
-const TRY_AGAIN_ON_ERR: Duration = Duration::from_secs(60 * 60);
-
 /// Protocol handler for sending and receiving identification requests.
 ///
 /// Outbound requests are sent periodically. The handler performs expects
 /// at least one identification request to be answered by the remote before
 /// permitting the underlying connection to be closed.
 pub struct IdentifyHandler {
-    /// Configuration for the protocol.
-    config: IdentifyProtocolConfig,
-
     /// Pending events to yield.
-    events: SmallVec<[IdentifyHandlerEvent; 4]>,
+    events: SmallVec<[ProtocolsHandlerEvent<
+            EitherUpgrade<IdentifyProtocol, IdentifyPushProtocol<OutboundPush>>,
+            (),
+            IdentifyHandlerEvent,
+            io::Error,
+    >; 4]>,
 
     /// Future that fires when we need to identify the node again.
     next_id: Delay,
 
     /// Whether the handler should keep the connection alive.
     keep_alive: KeepAlive,
+
+    /// The interval of `next_id`, i.e. the recurrent delay.
+    interval: Duration,
 }
 
 /// Event produced by the `IdentifyHandler`.
 #[derive(Debug)]
 pub enum IdentifyHandlerEvent {
-    /// We obtained identification information from the remote
-    Identified(RemoteInfo),
+    /// We obtained identification information from the remote.
+    Identified(IdentifyInfo),
     /// We received a request for identification.
     Identify(ReplySubstream<NegotiatedSubstream>),
     /// Failed to identify the remote.
-    IdentificationError(ProtocolsHandlerUpgrErr<ReadOneError>),
+    IdentificationError(ProtocolsHandlerUpgrErr<io::Error>),
 }
 
+/// Identifying information of the local node that is pushed to a remote.
+#[derive(Debug)]
+pub struct IdentifyPush(pub IdentifyInfo);
+
 impl IdentifyHandler {
     /// Creates a new `IdentifyHandler`.
-    pub fn new() -> Self {
+    pub fn new(initial_delay: Duration, interval: Duration) -> Self {
         IdentifyHandler {
-            config: IdentifyProtocolConfig,
             events: SmallVec::new(),
-            next_id: Delay::new(DELAY_TO_FIRST_ID),
+            next_id: Delay::new(initial_delay),
             keep_alive: KeepAlive::Yes,
+            interval,
         }
     }
 }
 
 impl ProtocolsHandler for IdentifyHandler {
-    type InEvent = ();
+    type InEvent = IdentifyPush;
     type OutEvent = IdentifyHandlerEvent;
-    type Error = ReadOneError;
-    type InboundProtocol = IdentifyProtocolConfig;
-    type OutboundProtocol = IdentifyProtocolConfig;
+    type Error = io::Error;
+    type InboundProtocol = SelectUpgrade<IdentifyProtocol, IdentifyPushProtocol<InboundPush>>;
+    type OutboundProtocol = EitherUpgrade<IdentifyProtocol, IdentifyPushProtocol<OutboundPush>>;
     type OutboundOpenInfo = ();
     type InboundOpenInfo = ();
 
     fn listen_protocol(&self) -> SubstreamProtocol<Self::InboundProtocol, Self::InboundOpenInfo> {
-        SubstreamProtocol::new(self.config.clone(), ())
+        SubstreamProtocol::new(
+            SelectUpgrade::new(
+                IdentifyProtocol,
+                IdentifyPushProtocol::inbound(),
+            ), ())
     }
 
     fn inject_fully_negotiated_inbound(
         &mut self,
-        protocol: <Self::InboundProtocol as InboundUpgrade<NegotiatedSubstream>>::Output,
-        _info: Self::InboundOpenInfo
+        output: <Self::InboundProtocol as InboundUpgrade<NegotiatedSubstream>>::Output,
+        _: Self::InboundOpenInfo
     ) {
-        self.events.push(IdentifyHandlerEvent::Identify(protocol))
+        match output {
+            EitherOutput::First(substream) => {
+                self.events.push(
+                    ProtocolsHandlerEvent::Custom(
+                        IdentifyHandlerEvent::Identify(substream)))
+            }
+            EitherOutput::Second(info) => {
+                self.events.push(
+                    ProtocolsHandlerEvent::Custom(
+                        IdentifyHandlerEvent::Identified(info)))
+            }
+        }
     }
 
     fn inject_fully_negotiated_outbound(
         &mut self,
-        protocol: <Self::OutboundProtocol as OutboundUpgrade<NegotiatedSubstream>>::Output,
-        _info: Self::OutboundOpenInfo,
+        output: <Self::OutboundProtocol as OutboundUpgrade<NegotiatedSubstream>>::Output,
+        _: Self::OutboundOpenInfo,
     ) {
-        self.events.push(IdentifyHandlerEvent::Identified(protocol));
-        self.keep_alive = KeepAlive::No;
+        match output {
+            EitherOutput::First(remote_info) => {
+                self.events.push(
+                    ProtocolsHandlerEvent::Custom(
+                        IdentifyHandlerEvent::Identified(remote_info)));
+                self.keep_alive = KeepAlive::No;
+            }
+            EitherOutput::Second(()) => {}
+        }
     }
 
-    fn inject_event(&mut self, _: Self::InEvent) {}
+    fn inject_event(&mut self, IdentifyPush(push): Self::InEvent) {
+        self.events.push(ProtocolsHandlerEvent::OutboundSubstreamRequest {
+            protocol: SubstreamProtocol::new(
+                EitherUpgrade::B(
+                    IdentifyPushProtocol::outbound(push)), ())
+        });
+    }
 
     fn inject_dial_upgrade_error(
         &mut self,
@@ -125,9 +168,16 @@ impl ProtocolsHandler for IdentifyHandler {
             <Self::OutboundProtocol as OutboundUpgrade<NegotiatedSubstream>>::Error
         >
     ) {
-        self.events.push(IdentifyHandlerEvent::IdentificationError(err));
+        let err = err.map_upgrade_err(|e| match e {
+            UpgradeError::Select(e) => UpgradeError::Select(e),
+            UpgradeError::Apply(EitherError::A(ioe)) => UpgradeError::Apply(ioe),
+            UpgradeError::Apply(EitherError::B(ioe)) => UpgradeError::Apply(ioe),
+        });
+        self.events.push(
+            ProtocolsHandlerEvent::Custom(
+                IdentifyHandlerEvent::IdentificationError(err)));
         self.keep_alive = KeepAlive::No;
-        self.next_id.reset(TRY_AGAIN_ON_ERR);
+        self.next_id.reset(self.interval);
     }
 
     fn connection_keep_alive(&self) -> KeepAlive {
@@ -143,18 +193,18 @@ impl ProtocolsHandler for IdentifyHandler {
         >,
     > {
         if !self.events.is_empty() {
-            return Poll::Ready(ProtocolsHandlerEvent::Custom(
+            return Poll::Ready(
                 self.events.remove(0),
-            ));
+            );
         }
 
         // Poll the future that fires when we need to identify the node again.
         match Future::poll(Pin::new(&mut self.next_id), cx) {
             Poll::Pending => Poll::Pending,
             Poll::Ready(Ok(())) => {
-                self.next_id.reset(DELAY_TO_NEXT_ID);
+                self.next_id.reset(self.interval);
                 let ev = ProtocolsHandlerEvent::OutboundSubstreamRequest {
-                    protocol: SubstreamProtocol::new(self.config.clone(), ())
+                    protocol: SubstreamProtocol::new(EitherUpgrade::A(IdentifyProtocol), ())
                 };
                 Poll::Ready(ev)
             }

protocols/identify/src/identify.rs

@@ -18,7 +18,7 @@
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-use crate::handler::{IdentifyHandler, IdentifyHandlerEvent};
+use crate::handler::{IdentifyHandler, IdentifyHandlerEvent, IdentifyPush};
 use crate::protocol::{IdentifyInfo, ReplySubstream};
 use futures::prelude::*;
 use libp2p_core::{
@@ -27,23 +27,26 @@ use libp2p_core::{
     PeerId,
     PublicKey,
     connection::ConnectionId,
-    upgrade::{ReadOneError, UpgradeError}
+    upgrade::UpgradeError
 };
 use libp2p_swarm::{
     AddressScore,
+    DialPeerCondition,
     NegotiatedSubstream,
     NetworkBehaviour,
     NetworkBehaviourAction,
+    NotifyHandler,
     PollParameters,
     ProtocolsHandler,
     ProtocolsHandlerUpgrErr
 };
 use std::{
-    collections::{HashMap, VecDeque},
+    collections::{HashSet, HashMap, VecDeque},
     io,
     pin::Pin,
     task::Context,
-    task::Poll
+    task::Poll,
+    time::Duration,
 };
 
 /// Network behaviour that automatically identifies nodes periodically, returns information
@@ -53,18 +56,16 @@ use std::{
 /// are reported via [`NetworkBehaviourAction::ReportObservedAddr`] with a
 /// [score](AddressScore) of `1`.
 pub struct Identify {
-    /// Protocol version to send back to remotes.
-    protocol_version: String,
-    /// Agent version to send back to remotes.
-    agent_version: String,
-    /// The public key of the local node. To report on the wire.
-    local_public_key: PublicKey,
+    config: IdentifyConfig,
     /// For each peer we're connected to, the observed address to send back to it.
-    observed_addresses: HashMap<PeerId, HashMap<ConnectionId, Multiaddr>>,
+    connected: HashMap<PeerId, HashMap<ConnectionId, Multiaddr>>,
     /// Pending replies to send.
     pending_replies: VecDeque<Reply>,
     /// Pending events to be emitted when polled.
-    events: VecDeque<NetworkBehaviourAction<(), IdentifyEvent>>,
+    events: VecDeque<NetworkBehaviourAction<IdentifyPush, IdentifyEvent>>,
+    /// Peers to which an active push with current information about
+    /// the local peer should be sent.
+    pending_push: HashSet<PeerId>,
 }
 
 /// A pending reply to an inbound identification request.
@@ -82,16 +83,92 @@ enum Reply {
     }
 }
 
+/// Configuration for the [`Identify`] [`NetworkBehaviour`].
+#[non_exhaustive]
+pub struct IdentifyConfig {
+    /// Application-specific version of the protocol family used by the peer,
+    /// e.g. `ipfs/1.0.0` or `polkadot/1.0.0`.
+    pub protocol_version: String,
+    /// The public key of the local node. To report on the wire.
+    pub local_public_key: PublicKey,
+    /// Name and version of the local peer implementation, similar to the
+    /// `User-Agent` header in the HTTP protocol.
+    ///
+    /// Defaults to `rust-libp2p/<libp2p-identify-version>`.
+    pub agent_version: String,
+    /// The initial delay before the first identification request
+    /// is sent to a remote on a newly established connection.
+    ///
+    /// Defaults to 500ms.
+    pub initial_delay: Duration,
+    /// The interval at which identification requests are sent to
+    /// the remote on established connections after the first request,
+    /// i.e. the delay between identification requests.
+    ///
+    /// Defaults to 5 minutes.
+    pub interval: Duration,
+}
+
+impl IdentifyConfig {
+    /// Creates a new configuration for the `Identify` behaviour that
+    /// advertises the given protocol version and public key.
+    pub fn new(protocol_version: String, local_public_key: PublicKey) -> Self {
+        IdentifyConfig {
+            protocol_version,
+            agent_version: format!("rust-libp2p/{}", env!("CARGO_PKG_VERSION")),
+            local_public_key,
+            initial_delay: Duration::from_millis(500),
+            interval: Duration::from_secs(5 * 60),
+        }
+    }
+
+    /// Configures the agent version sent to peers.
+    pub fn with_agent_version(mut self, v: String) -> Self {
+        self.agent_version = v;
+        self
+    }
+
+    /// Configures the initial delay before the first identification
+    /// request is sent on a newly established connection to a peer.
+    pub fn with_initial_delay(mut self, d: Duration) -> Self {
+        self.initial_delay = d;
+        self
+    }
+
+    /// Configures the interval at which identification requests are
+    /// sent to peers after the initial request.
+    pub fn with_interval(mut self, d: Duration) -> Self {
+        self.interval = d;
+        self
+    }
+}
+
 impl Identify {
     /// Creates a new `Identify` network behaviour.
-    pub fn new(protocol_version: String, agent_version: String, local_public_key: PublicKey) -> Self {
+    pub fn new(config: IdentifyConfig) -> Self {
         Identify {
-            protocol_version,
-            agent_version,
-            local_public_key,
-            observed_addresses: HashMap::new(),
+            config,
+            connected: HashMap::new(),
             pending_replies: VecDeque::new(),
             events: VecDeque::new(),
+            pending_push: HashSet::new(),
+        }
+    }
+
+    /// Initiates an active push of the local peer information to the given peers.
+    pub fn push<I>(&mut self, peers: I)
+    where
+        I: IntoIterator<Item = PeerId>
+    {
+        for p in peers {
+            if self.pending_push.insert(p) {
+                if !self.connected.contains_key(&p) {
+                    self.events.push_back(NetworkBehaviourAction::DialPeer {
+                        peer_id: p,
+                        condition: DialPeerCondition::Disconnected
+                    });
+                }
+            }
         }
     }
 }
@@ -101,7 +178,7 @@ impl NetworkBehaviour for Identify {
     type OutEvent = IdentifyEvent;
 
     fn new_handler(&mut self) -> Self::ProtocolsHandler {
-        IdentifyHandler::new()
+        IdentifyHandler::new(self.config.initial_delay, self.config.interval)
     }
 
     fn addresses_of_peer(&mut self, _: &PeerId) -> Vec<Multiaddr> {
@@ -117,17 +194,24 @@ impl NetworkBehaviour for Identify {
             ConnectedPoint::Listener { send_back_addr, .. } => send_back_addr.clone(),
         };
 
-        self.observed_addresses.entry(*peer_id).or_default().insert(*conn, addr);
+        self.connected.entry(*peer_id).or_default().insert(*conn, addr.clone());
     }
 
     fn inject_connection_closed(&mut self, peer_id: &PeerId, conn: &ConnectionId, _: &ConnectedPoint) {
-        if let Some(addrs) = self.observed_addresses.get_mut(peer_id) {
+        if let Some(addrs) = self.connected.get_mut(peer_id) {
             addrs.remove(conn);
         }
     }
 
+    fn inject_dial_failure(&mut self, peer_id: &PeerId) {
+        if !self.connected.contains_key(peer_id) {
+            self.pending_push.remove(peer_id);
+        }
+    }
+
     fn inject_disconnected(&mut self, peer_id: &PeerId) {
-        self.observed_addresses.remove(peer_id);
+        self.connected.remove(peer_id);
+        self.pending_push.remove(peer_id);
     }
 
     fn inject_event(
@@ -137,22 +221,22 @@ impl NetworkBehaviour for Identify {
         event: <Self::ProtocolsHandler as ProtocolsHandler>::OutEvent,
     ) {
         match event {
-            IdentifyHandlerEvent::Identified(remote) => {
+            IdentifyHandlerEvent::Identified(info) => {
+                let observed = info.observed_addr.clone();
                 self.events.push_back(
                     NetworkBehaviourAction::GenerateEvent(
                         IdentifyEvent::Received {
                             peer_id,
-                            info: remote.info,
-                            observed_addr: remote.observed_addr.clone(),
+                            info,
                         }));
                 self.events.push_back(
                     NetworkBehaviourAction::ReportObservedAddr {
-                        address: remote.observed_addr,
+                        address: observed,
                         score: AddressScore::Finite(1),
                     });
             }
             IdentifyHandlerEvent::Identify(sender) => {
-                let observed = self.observed_addresses.get(&peer_id)
+                let observed = self.connected.get(&peer_id)
                     .and_then(|addrs| addrs.get(&connection))
                     .expect("`inject_event` is only called with an established connection \
                              and `inject_connection_established` ensures there is an entry; qed");
@@ -185,17 +269,42 @@ impl NetworkBehaviour for Identify {
             return Poll::Ready(event);
         }
 
+        // Check for a pending active push to perform.
+        let peer_push = self.pending_push.iter().find_map(|peer| {
+            self.connected.get(peer).map(|conns| {
+                let observed_addr = conns
+                    .values()
+                    .next()
+                    .expect("connected peer has a connection")
+                    .clone();
+
+                let listen_addrs = listen_addrs(params);
+                let protocols = supported_protocols(params);
+
+                let info = IdentifyInfo {
+                    public_key: self.config.local_public_key.clone(),
+                    protocol_version: self.config.protocol_version.clone(),
+                    agent_version: self.config.agent_version.clone(),
+                    listen_addrs,
+                    protocols,
+                    observed_addr,
+                };
+
+                (*peer, IdentifyPush(info))
+            })
+        });
+
+        if let Some((peer_id, push)) = peer_push {
+            self.pending_push.remove(&peer_id);
+            return Poll::Ready(NetworkBehaviourAction::NotifyHandler {
+                peer_id,
+                event: push,
+                handler: NotifyHandler::Any,
+            })
+        }
+
+        // Check for pending replies to send.
         if let Some(r) = self.pending_replies.pop_front() {
-            // The protocol names can be bytes, but the identify protocol except UTF-8 strings.
-            // There's not much we can do to solve this conflict except strip non-UTF-8 characters.
-            let protocols: Vec<_> = params
-                .supported_protocols()
-                .map(|p| String::from_utf8_lossy(&p).to_string())
-                .collect();
-
-            let mut listen_addrs: Vec<_> = params.external_addresses().map(|r| r.addr).collect();
-            listen_addrs.extend(params.listened_addresses());
-
             let mut sending = 0;
             let to_send = self.pending_replies.len() + 1;
             let mut reply = Some(r);
@@ -203,13 +312,14 @@ impl NetworkBehaviour for Identify {
                 match reply {
                     Some(Reply::Queued { peer, io, observed }) => {
                         let info = IdentifyInfo {
-                            public_key: self.local_public_key.clone(),
-                            protocol_version: self.protocol_version.clone(),
-                            agent_version: self.agent_version.clone(),
-                            listen_addrs: listen_addrs.clone(),
-                            protocols: protocols.clone(),
+                            listen_addrs: listen_addrs(params),
+                            protocols: supported_protocols(params),
+                            public_key: self.config.local_public_key.clone(),
+                            protocol_version: self.config.protocol_version.clone(),
+                            agent_version: self.config.agent_version.clone(),
+                            observed_addr: observed,
                         };
-                        let io = Box::pin(io.send(info, &observed));
+                        let io = Box::pin(io.send(info));
                         reply = Some(Reply::Sending { peer, io });
                     }
                     Some(Reply::Sending { peer, mut io }) => {
@@ -255,8 +365,6 @@ pub enum IdentifyEvent {
         peer_id: PeerId,
         /// The information provided by the peer.
         info: IdentifyInfo,
-        /// The address observed by the peer for the local node.
-        observed_addr: Multiaddr,
     },
     /// Identifying information of the local node has been sent to a peer.
     Sent {
@@ -268,14 +376,29 @@ pub enum IdentifyEvent {
         /// The peer with whom the error originated.
         peer_id: PeerId,
         /// The error that occurred.
-        error: ProtocolsHandlerUpgrErr<ReadOneError>,
+        error: ProtocolsHandlerUpgrErr<io::Error>,
     },
 }
 
+fn supported_protocols(params: &impl PollParameters) -> Vec<String> {
+    // The protocol names can be bytes, but the identify protocol except UTF-8 strings.
+    // There's not much we can do to solve this conflict except strip non-UTF-8 characters.
+    params
+        .supported_protocols()
+        .map(|p| String::from_utf8_lossy(&p).to_string())
+        .collect()
+}
+
+fn listen_addrs(params: &impl PollParameters) -> Vec<Multiaddr> {
+    let mut listen_addrs: Vec<_> = params.external_addresses().map(|r| r.addr).collect();
+    listen_addrs.extend(params.listened_addresses());
+    listen_addrs
+}
+
 #[cfg(test)]
 mod tests {
-    use crate::{Identify, IdentifyEvent};
-    use futures::{prelude::*, pin_mut};
+    use super::*;
+    use futures::pin_mut;
     use libp2p_core::{
         identity,
         PeerId,
@@ -303,17 +426,21 @@ mod tests {
     }
 
     #[test]
-    fn periodic_id_works() {
+    fn periodic_identify() {
         let (mut swarm1, pubkey1) = {
             let (pubkey, transport) = transport();
-            let protocol = Identify::new("a".to_string(), "b".to_string(), pubkey.clone());
+            let protocol = Identify::new(
+                IdentifyConfig::new("a".to_string(), pubkey.clone())
+                    .with_agent_version("b".to_string()));
             let swarm = Swarm::new(transport, protocol, pubkey.clone().into_peer_id());
             (swarm, pubkey)
         };
 
         let (mut swarm2, pubkey2) = {
             let (pubkey, transport) = transport();
-            let protocol = Identify::new("c".to_string(), "d".to_string(), pubkey.clone());
+            let protocol = Identify::new(
+                IdentifyConfig::new("c".to_string(), pubkey.clone())
+                    .with_agent_version("d".to_string()));
             let swarm = Swarm::new(transport, protocol, pubkey.clone().into_peer_id());
             (swarm, pubkey)
         };
@@ -365,4 +492,76 @@ mod tests {
             }
         })
     }
+
+    #[test]
+    fn identify_push() {
+        let _ = env_logger::try_init();
+
+        let (mut swarm1, pubkey1) = {
+            let (pubkey, transport) = transport();
+            let protocol = Identify::new(
+                IdentifyConfig::new("a".to_string(), pubkey.clone())
+                    // Delay identification requests so we can test the push protocol.
+                    .with_initial_delay(Duration::from_secs(u32::MAX as u64)));
+            let swarm = Swarm::new(transport, protocol, pubkey.clone().into_peer_id());
+            (swarm, pubkey)
+        };
+
+        let (mut swarm2, pubkey2) = {
+            let (pubkey, transport) = transport();
+            let protocol = Identify::new(
+                IdentifyConfig::new("a".to_string(), pubkey.clone())
+                    .with_agent_version("b".to_string())
+                    // Delay identification requests so we can test the push protocol.
+                    .with_initial_delay(Duration::from_secs(u32::MAX as u64)));
+            let swarm = Swarm::new(transport, protocol, pubkey.clone().into_peer_id());
+            (swarm, pubkey)
+        };
+
+        Swarm::listen_on(&mut swarm1, "/ip4/127.0.0.1/tcp/0".parse().unwrap()).unwrap();
+
+        let listen_addr = async_std::task::block_on(async {
+            loop {
+                let swarm1_fut = swarm1.next_event();
+                pin_mut!(swarm1_fut);
+                match swarm1_fut.await {
+                    SwarmEvent::NewListenAddr(addr) => return addr,
+                    _ => {}
+                }
+            }
+        });
+
+        Swarm::dial_addr(&mut swarm2, listen_addr).unwrap();
+
+        async_std::task::block_on(async move {
+            loop {
+                let swarm1_fut = swarm1.next_event();
+                let swarm2_fut = swarm2.next_event();
+
+                {
+                    pin_mut!(swarm1_fut);
+                    pin_mut!(swarm2_fut);
+                    match future::select(swarm1_fut, swarm2_fut).await.factor_second().0 {
+                        future::Either::Left(SwarmEvent::Behaviour(
+                            IdentifyEvent::Received { info, .. }
+                        )) => {
+                            assert_eq!(info.public_key, pubkey2);
+                            assert_eq!(info.protocol_version, "a");
+                            assert_eq!(info.agent_version, "b");
+                            assert!(!info.protocols.is_empty());
+                            assert!(info.listen_addrs.is_empty());
+                            return;
+                        }
+                        future::Either::Right(SwarmEvent::ConnectionEstablished { .. }) => {
+                            // Once a connection is established, we can initiate an
+                            // active push below.
+                        }
+                        _ => { continue }
+                    }
+                }
+
+                swarm2.push(std::iter::once(pubkey1.clone().into_peer_id()));
+            }
+        })
+    }
 }

protocols/identify/src/lib.rs

@@ -35,9 +35,9 @@
 //! [Identify]: https://github.com/libp2p/specs/tree/master/identify
 //! [`Identify`]: self::Identify
 //! [`IdentifyEvent`]: self::IdentifyEvent
-//! [`IdentifyInfo`]: self::IdentifyEvent
+//! [`IdentifyInfo`]: self::IdentifyInfo
 
-pub use self::identify::{Identify, IdentifyEvent};
+pub use self::identify::{Identify, IdentifyConfig, IdentifyEvent};
 pub use self::protocol::IdentifyInfo;
 
 mod handler;

protocols/identify/src/protocol.rs

@@ -30,16 +30,44 @@ use prost::Message;
 use std::convert::TryFrom;
 use std::{fmt, io, iter, pin::Pin};
 
-/// Configuration for an upgrade to the `Identify` protocol.
+/// Substream upgrade protocol for `/ipfs/id/1.0.0`.
 #[derive(Debug, Clone)]
-pub struct IdentifyProtocolConfig;
+pub struct IdentifyProtocol;
 
+/// Substream upgrade protocol for `/ipfs/id/push/1.0.0`.
 #[derive(Debug, Clone)]
-#[non_exhaustive]
-pub struct RemoteInfo {
-    /// Information about the remote.
-    pub info: IdentifyInfo,
-    /// Address the remote sees for us.
+pub struct IdentifyPushProtocol<T>(T);
+pub struct InboundPush();
+pub struct OutboundPush(IdentifyInfo);
+
+impl IdentifyPushProtocol<InboundPush> {
+    pub fn inbound() -> Self {
+        IdentifyPushProtocol(InboundPush())
+    }
+}
+
+impl IdentifyPushProtocol<OutboundPush> {
+    pub fn outbound(info: IdentifyInfo) -> Self {
+        IdentifyPushProtocol(OutboundPush(info))
+    }
+}
+
+/// Information of a peer sent in protocol messages.
+#[derive(Debug, Clone)]
+pub struct IdentifyInfo {
+    /// The public key of the local peer.
+    pub public_key: PublicKey,
+    /// Application-specific version of the protocol family used by the peer,
+    /// e.g. `ipfs/1.0.0` or `polkadot/1.0.0`.
+    pub protocol_version: String,
+    /// Name and version of the peer, similar to the `User-Agent` header in
+    /// the HTTP protocol.
+    pub agent_version: String,
+    /// The addresses that the peer is listening on.
+    pub listen_addrs: Vec<Multiaddr>,
+    /// The list of protocols supported by the peer, e.g. `/ipfs/ping/1.0.0`.
+    pub protocols: Vec<String>,
+    /// Address observed by or for the remote.
     pub observed_addr: Multiaddr,
 }
 
@@ -60,56 +88,14 @@ where
 {
     /// Sends back the requested information on the substream.
     ///
-    /// Consumes the substream, returning a `ReplyFuture` that resolves
+    /// Consumes the substream, returning a future that resolves
     /// when the reply has been sent on the underlying connection.
-    pub fn send(mut self, info: IdentifyInfo, observed_addr: &Multiaddr)
-        -> impl Future<Output = Result<(), io::Error>>
-    {
-        debug!("Sending identify info to client");
-        trace!("Sending: {:?}", info);
-
-        let listen_addrs = info.listen_addrs
-            .into_iter()
-            .map(|addr| addr.to_vec())
-            .collect();
-
-        let pubkey_bytes = info.public_key.into_protobuf_encoding();
-
-        let message = structs_proto::Identify {
-            agent_version: Some(info.agent_version),
-            protocol_version: Some(info.protocol_version),
-            public_key: Some(pubkey_bytes),
-            listen_addrs,
-            observed_addr: Some(observed_addr.to_vec()),
-            protocols: info.protocols
-        };
-
-        async move {
-            let mut bytes = Vec::with_capacity(message.encoded_len());
-            message.encode(&mut bytes).expect("Vec<u8> provides capacity as needed");
-            upgrade::write_one(&mut self.inner, &bytes).await
-        }
+    pub async fn send(self, info: IdentifyInfo) -> io::Result<()> {
+        send(self.inner, info).await
     }
 }
 
-/// Information of a peer sent in `Identify` protocol responses.
-#[derive(Debug, Clone)]
-pub struct IdentifyInfo {
-    /// The public key underlying the peer's `PeerId`.
-    pub public_key: PublicKey,
-    /// Version of the protocol family used by the peer, e.g. `ipfs/1.0.0`
-    /// or `polkadot/1.0.0`.
-    pub protocol_version: String,
-    /// Name and version of the peer, similar to the `User-Agent` header in
-    /// the HTTP protocol.
-    pub agent_version: String,
-    /// The addresses that the peer is listening on.
-    pub listen_addrs: Vec<Multiaddr>,
-    /// The list of protocols supported by the peer, e.g. `/ipfs/ping/1.0.0`.
-    pub protocols: Vec<String>,
-}
-
-impl UpgradeInfo for IdentifyProtocolConfig {
+impl UpgradeInfo for IdentifyProtocol {
     type Info = &'static [u8];
     type InfoIter = iter::Once<Self::Info>;
 
@@ -118,59 +104,119 @@ impl UpgradeInfo for IdentifyProtocolConfig {
     }
 }
 
-impl<C> InboundUpgrade<C> for IdentifyProtocolConfig
-where
-    C: AsyncRead + AsyncWrite + Unpin,
-{
+impl<C> InboundUpgrade<C> for IdentifyProtocol {
     type Output = ReplySubstream<C>;
     type Error = io::Error;
     type Future = future::Ready<Result<Self::Output, io::Error>>;
 
     fn upgrade_inbound(self, socket: C, _: Self::Info) -> Self::Future {
-        trace!("Upgrading inbound connection");
         future::ok(ReplySubstream { inner: socket })
     }
 }
 
-impl<C> OutboundUpgrade<C> for IdentifyProtocolConfig
+impl<C> OutboundUpgrade<C> for IdentifyProtocol
 where
     C: AsyncRead + AsyncWrite + Unpin + Send + 'static,
 {
-    type Output = RemoteInfo;
-    type Error = upgrade::ReadOneError;
+    type Output = IdentifyInfo;
+    type Error = io::Error;
     type Future = Pin<Box<dyn Future<Output = Result<Self::Output, Self::Error>> + Send>>;
 
-    fn upgrade_outbound(self, mut socket: C, _: Self::Info) -> Self::Future {
-        Box::pin(async move {
-            socket.close().await?;
-            let msg = upgrade::read_one(&mut socket, 4096).await?;
-            let (info, observed_addr) = match parse_proto_msg(msg) {
-                Ok(v) => v,
-                Err(err) => {
-                    debug!("Failed to parse protobuf message; error = {:?}", err);
-                    return Err(err.into())
-                }
-            };
-
-            trace!("Remote observes us as {:?}", observed_addr);
-            trace!("Information received: {:?}", info);
-
-            Ok(RemoteInfo {
-                info,
-                observed_addr,
-            })
-        })
+    fn upgrade_outbound(self, socket: C, _: Self::Info) -> Self::Future {
+        recv(socket).boxed()
     }
 }
 
-// Turns a protobuf message into an `IdentifyInfo` and an observed address. If something bad
-// happens, turn it into an `io::Error`.
-fn parse_proto_msg(msg: impl AsRef<[u8]>) -> Result<(IdentifyInfo, Multiaddr), io::Error> {
+impl<T> UpgradeInfo for IdentifyPushProtocol<T> {
+    type Info = &'static [u8];
+    type InfoIter = iter::Once<Self::Info>;
+
+    fn protocol_info(&self) -> Self::InfoIter {
+        iter::once(b"/ipfs/id/push/1.0.0")
+    }
+}
+
+impl<C> InboundUpgrade<C> for IdentifyPushProtocol<InboundPush>
+where
+    C: AsyncRead + AsyncWrite + Unpin + Send + 'static,
+{
+    type Output = IdentifyInfo;
+    type Error = io::Error;
+    type Future = Pin<Box<dyn Future<Output = Result<Self::Output, Self::Error>> + Send>>;
+
+    fn upgrade_inbound(self, socket: C, _: Self::Info) -> Self::Future {
+        recv(socket).boxed()
+    }
+}
+
+impl<C> OutboundUpgrade<C> for IdentifyPushProtocol<OutboundPush>
+where
+    C: AsyncWrite + Unpin + Send + 'static,
+{
+    type Output = ();
+    type Error = io::Error;
+    type Future = Pin<Box<dyn Future<Output = Result<Self::Output, Self::Error>> + Send>>;
+
+    fn upgrade_outbound(self, socket: C, _: Self::Info) -> Self::Future {
+        send(socket, self.0.0).boxed()
+    }
+}
+
+async fn send<T>(mut io: T, info: IdentifyInfo) -> io::Result<()>
+where
+    T: AsyncWrite + Unpin
+{
+    trace!("Sending: {:?}", info);
+
+    let listen_addrs = info.listen_addrs
+        .into_iter()
+        .map(|addr| addr.to_vec())
+        .collect();
+
+    let pubkey_bytes = info.public_key.into_protobuf_encoding();
+
+    let message = structs_proto::Identify {
+        agent_version: Some(info.agent_version),
+        protocol_version: Some(info.protocol_version),
+        public_key: Some(pubkey_bytes),
+        listen_addrs,
+        observed_addr: Some(info.observed_addr.to_vec()),
+        protocols: info.protocols
+    };
+
+    let mut bytes = Vec::with_capacity(message.encoded_len());
+    message.encode(&mut bytes).expect("Vec<u8> provides capacity as needed");
+    upgrade::write_one(&mut io, &bytes).await
+}
+
+async fn recv<T>(mut socket: T) -> io::Result<IdentifyInfo>
+where
+    T: AsyncRead + AsyncWrite + Unpin
+{
+    socket.close().await?;
+
+    let msg = upgrade::read_one(&mut socket, 4096)
+        .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))
+        .await?;
+
+    let info = match parse_proto_msg(msg) {
+        Ok(v) => v,
+        Err(err) => {
+            debug!("Invalid message: {:?}", err);
+            return Err(err.into())
+        }
+    };
+
+    trace!("Received: {:?}", info);
+
+    Ok(info)
+}
+
+/// Turns a protobuf message into an `IdentifyInfo`.
+fn parse_proto_msg(msg: impl AsRef<[u8]>) -> Result<IdentifyInfo, io::Error> {
     match structs_proto::Identify::decode(msg.as_ref()) {
         Ok(msg) => {
-            // Turn a `Vec<u8>` into a `Multiaddr`. If something bad happens, turn it into
-            // an `io::Error`.
-            fn bytes_to_multiaddr(bytes: Vec<u8>) -> Result<Multiaddr, io::Error> {
+            fn parse_multiaddr(bytes: Vec<u8>) -> Result<Multiaddr, io::Error> {
                 Multiaddr::try_from(bytes)
                     .map_err(|err| io::Error::new(io::ErrorKind::InvalidData, err))
             }
@@ -178,7 +224,7 @@ fn parse_proto_msg(msg: impl AsRef<[u8]>) -> Result<(IdentifyInfo, Multiaddr), i
             let listen_addrs = {
                 let mut addrs = Vec::new();
                 for addr in msg.listen_addrs.into_iter() {
-                    addrs.push(bytes_to_multiaddr(addr)?);
+                    addrs.push(parse_multiaddr(addr)?);
                 }
                 addrs
             };
@@ -186,16 +232,17 @@ fn parse_proto_msg(msg: impl AsRef<[u8]>) -> Result<(IdentifyInfo, Multiaddr), i
             let public_key = PublicKey::from_protobuf_encoding(&msg.public_key.unwrap_or_default())
                 .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))?;
 
-            let observed_addr = bytes_to_multiaddr(msg.observed_addr.unwrap_or_default())?;
+            let observed_addr = parse_multiaddr(msg.observed_addr.unwrap_or_default())?;
             let info = IdentifyInfo {
                 public_key,
                 protocol_version: msg.protocol_version.unwrap_or_default(),
                 agent_version: msg.agent_version.unwrap_or_default(),
                 listen_addrs,
-                protocols: msg.protocols
+                protocols: msg.protocols,
+                observed_addr,
             };
 
-            Ok((info, observed_addr))
+            Ok(info)
         }
 
         Err(err) => Err(io::Error::new(io::ErrorKind::InvalidData, err)),
@@ -204,7 +251,6 @@ fn parse_proto_msg(msg: impl AsRef<[u8]>) -> Result<(IdentifyInfo, Multiaddr), i
 
 #[cfg(test)]
 mod tests {
-    use crate::protocol::{IdentifyInfo, RemoteInfo, IdentifyProtocolConfig};
     use libp2p_tcp::TcpConfig;
     use futures::{prelude::*, channel::oneshot};
     use libp2p_core::{
@@ -212,6 +258,7 @@ mod tests {
         Transport,
         upgrade::{self, apply_outbound, apply_inbound}
     };
+    use super::*;
 
     #[test]
     fn correct_transfer() {
@@ -236,8 +283,13 @@ mod tests {
                 .expect("listen address");
             tx.send(addr).unwrap();
 
-            let socket = listener.next().await.unwrap().unwrap().into_upgrade().unwrap().0.await.unwrap();
-            let sender = apply_inbound(socket, IdentifyProtocolConfig).await.unwrap();
+            let socket = listener
+                .next().await.unwrap().unwrap()
+                .into_upgrade().unwrap()
+                .0.await.unwrap();
+
+            let sender = apply_inbound(socket, IdentifyProtocol).await.unwrap();
+
             sender.send(
                 IdentifyInfo {
                     public_key: send_pubkey,
@@ -248,8 +300,8 @@ mod tests {
                         "/ip6/::1/udp/1000".parse().unwrap(),
                     ],
                     protocols: vec!["proto1".to_string(), "proto2".to_string()],
+                    observed_addr: "/ip4/100.101.102.103/tcp/5000".parse().unwrap(),
                 },
-                &"/ip4/100.101.102.103/tcp/5000".parse().unwrap(),
             ).await.unwrap();
         });
 
@@ -257,9 +309,12 @@ mod tests {
             let transport = TcpConfig::new();
 
             let socket = transport.dial(rx.await.unwrap()).unwrap().await.unwrap();
-            let RemoteInfo { info, observed_addr, .. } =
-                apply_outbound(socket, IdentifyProtocolConfig, upgrade::Version::V1).await.unwrap();
-            assert_eq!(observed_addr, "/ip4/100.101.102.103/tcp/5000".parse().unwrap());
+            let info = apply_outbound(
+                socket,
+                IdentifyProtocol,
+                upgrade::Version::V1
+            ).await.unwrap();
+            assert_eq!(info.observed_addr, "/ip4/100.101.102.103/tcp/5000".parse().unwrap());
             assert_eq!(info.public_key, recv_pubkey);
             assert_eq!(info.protocol_version, "proto_version");
             assert_eq!(info.agent_version, "agent_version");

protocols/relay/tests/lib.rs

@@ -30,7 +30,7 @@ use libp2p_core::multiaddr::{Multiaddr, Protocol};
 use libp2p_core::transport::{MemoryTransport, Transport, TransportError};
 use libp2p_core::upgrade::{DeniedUpgrade, InboundUpgrade, OutboundUpgrade};
 use libp2p_core::{identity, upgrade, PeerId};
-use libp2p_identify::{Identify, IdentifyEvent, IdentifyInfo};
+use libp2p_identify::{Identify, IdentifyConfig, IdentifyEvent, IdentifyInfo};
 use libp2p_kad::{GetClosestPeersOk, Kademlia, KademliaEvent, QueryResult};
 use libp2p_ping::{Ping, PingConfig, PingEvent};
 use libp2p_plaintext::PlainText2Config;
@@ -1238,11 +1238,10 @@ fn build_swarm(reachability: Reachability, relay_mode: RelayMode) -> Swarm<Combi
             local_peer_id.clone(),
             MemoryStore::new(local_peer_id.clone()),
         ),
-        identify: Identify::new(
+        identify: Identify::new(IdentifyConfig::new(
             "test".to_string(),
-            "test-agent".to_string(),
             local_public_key.clone(),
-        ),
+        )),
         events: Default::default(),
     };