//! Implement a concrete type to build channels over a transport.

use async_trait::async_trait;

use futures::{AsyncRead, AsyncWrite};

use std::io;

use std::sync::{Arc, Mutex};

use std::time::Duration;

use tracing::instrument;

use crate::factory::{BootstrapReporter, ChannelFactory, IncomingChannelFactory};

use crate::transport::TransportImplHelper;

use crate::{Error, event::ChanMgrEventSender};

use safelog::MaybeSensitive;

use tor_basic_utils::rand_hostname;

use tor_error::internal;

use tor_linkspec::{ChanTarget, HasChanMethod, IntoOwnedChanTarget, OwnedChanTarget};

use tor_proto::channel::ChannelType;

use tor_proto::channel::kist::KistParams;

use tor_proto::channel::params::ChannelPaddingInstructionsUpdates;

use tor_proto::memquota::ChannelAccount;

use tor_proto::peer::PeerAddr;

use tor_rtcompat::SpawnExt;

use tor_rtcompat::{CertifiedConn, Runtime, StreamOps, TlsProvider, tls::TlsConnector};

#[cfg(feature = "relay")]

use {

    safelog::Sensitive, std::net::SocketAddr, tor_error::bad_api_usage,

    tor_proto::RelayChannelAuthMaterial, tor_proto::relay::CreateRequestHandler,

};

/// TLS-based channel builder.

///

/// This is a separate type so that we can keep our channel management code

/// network-agnostic.

///

/// It uses a provided `TransportHelper` type to make a connection (possibly

/// directly over TCP, and possibly over some other protocol).  It then

/// negotiates TLS over that connection, and negotiates a Tor channel over that

/// TLS session.

///

/// This channel builder does not retry on failure, but it _does_ implement a

/// time-out.

pub struct ChanBuilder<R: Runtime, H: TransportImplHelper>

where

    R: tor_rtcompat::TlsProvider<H::Stream>,

{

    /// Asynchronous runtime for TLS, TCP, spawning, and timeouts.

    runtime: R,

    /// The transport object that we use to construct streams.

    transport: H,

    /// Object to build TLS connections.

    tls_connector: <R as TlsProvider<H::Stream>>::Connector,

    /// Object to accept TLS connections.

    #[cfg(feature = "relay")]

    tls_acceptor: Option<<R as TlsProvider<H::Stream>>::Acceptor>,

    /// Relay authentication key material needed for relay channels.

    #[cfg(feature = "relay")]

    auth_material: Option<Arc<RelayChannelAuthMaterial>>,

    /// Our address(es) to use in the NETINFO cell.

    // TODO: We might want one day to support updating the addresses here in the same way we

    // support updating the auth_material. One use case for this is the relay config reload.

    #[cfg(feature = "relay")]

    my_addrs: Vec<SocketAddr>,

    /// Provided to each new channel so that they can handle CREATE* requests.

    #[cfg(feature = "relay")]

    create_request_handler: Option<Arc<CreateRequestHandler>>,

}

impl<R: Runtime, H: TransportImplHelper> ChanBuilder<R, H>

where

    R: TlsProvider<H::Stream>,

{

    /// Construct a new client specific ChanBuilder.

    /// Construct a new relay specific ChanBuilder.

    #[cfg(feature = "relay")]

        use tor_error::into_internal;

        use tor_rtcompat::tls::TlsAcceptorSettings;

        // Build the TLS acceptor.

        // Same builder as a client but with auth material and acceptor.

    /// Build a new `ChanBuilder` with the given `auth_material`,

    /// cloning everything else.

    ///

    /// This is needed because some relay keys rotate over time.

    #[cfg(feature = "relay")]

    {

        )

    /// Build a new `ChanBuilder` with the given CREATE* request `handler`,

    /// cloning everything else.

    ///

    /// This is needed so that we can set the handler,

    /// which isn't known when the builder is initially created.

    #[cfg(feature = "relay")]

    {

        )

    /// Return the outbound channel type of this config.

    ///

    /// The channel type is used when creating outbound channels. Relays always initiate channels

    /// as "relay initiator" while client and bridges behave like a "client initiator".

    ///

    /// Important: The wrong channel type is returned if this is called before `with_identities()`

    /// is called.

        #[cfg(feature = "relay")]

}

#[async_trait]

impl<R: Runtime, H: TransportImplHelper> ChannelFactory for ChanBuilder<R, H>

where

    R: tor_rtcompat::TlsProvider<H::Stream> + Send + Sync,

    H: Send + Sync,

{

    #[instrument(skip_all, level = "trace")]

    async fn connect_via_transport(

        &self,

        target: &OwnedChanTarget,

        reporter: BootstrapReporter,

        memquota: ChannelAccount,

    ) -> crate::Result<Arc<tor_proto::channel::Channel>> {

        use tor_rtcompat::SleepProviderExt;

        // TODO: make this an option.  And make a better value.

        let delay = if target.chan_method().is_direct() {

            std::time::Duration::new(5, 0)

        } else {

            std::time::Duration::new(10, 0)

        };

        self.runtime

            .timeout(delay, self.connect_no_timeout(target, reporter.0, memquota))

            .await

            .map_err(|_| Error::ChanTimeout {

    }

}

#[async_trait]

impl<R: Runtime, H: TransportImplHelper> IncomingChannelFactory for ChanBuilder<R, H>

where

    R: tor_rtcompat::TlsProvider<H::Stream> + Send + Sync,

    H: Send + Sync,

{

    type Stream = H::Stream;

    #[cfg(feature = "relay")]

    async fn accept_from_transport(

        &self,

        peer: Sensitive<std::net::SocketAddr>,

        stream: Self::Stream,

        memquota: ChannelAccount,

        use tor_linkspec::OwnedChanTargetBuilder;

        use tor_proto::relay::MaybeVerifiableRelayResponderChannel;

        // Note that as we accept a connection, we don't expect any specific identities and so we

        // can only build a target from the peer address. This means that the verification process

        // will not match the identities seen (if a relay <-> relay channel) to this target which

        // is fine as we are a responder.

        let target_no_ids = OwnedChanTargetBuilder::default()

            .addrs(vec![peer.into_inner()])

            .build()

        // Convert into a PeerAddr but keep it sensitive, this can be a client/bridge.

        let peer_addr: MaybeSensitive<PeerAddr> =

            MaybeSensitive::sensitive(peer.into_inner().into());

        // Helpers: For error mapping.

        let map_ioe = |ioe, action| Error::Io {

        let map_proto = |source, target: &OwnedChanTarget, clock_skew| Error::Proto {

        let tls = self

            .tls_acceptor

            .as_ref()

            .ok_or(internal!("Accepting connection without TLS acceptor"))?

            .negotiate_unvalidated(stream, "ignored")

            .await

        let auth_material = self

            .auth_material

            .as_ref()

            .ok_or(internal!(

                "Unable to build relay channel without auth material"

            ))?

            .clone();

        let our_cert = tls

            .own_certificate()

            .into_owned();

        let builder = tor_proto::RelayChannelBuilder::new();

        let unverified = builder

            .accept(

                Sensitive::new(peer_addr.inner()),

                self.my_addrs.clone(),

                tls,

                self.runtime.clone(),

                auth_material,

                memquota,

                Arc::clone(create_request_handler),

            )

            .await

        let (chan, reactor) = match unverified {

            MaybeVerifiableRelayResponderChannel::Verifiable(c) => {

                let clock_skew = c.clock_skew();

                let now = self.runtime.wallclock();

                c.verify(&target_no_ids, &our_cert, Some(now))

                    .finish()

                    .await

            }

            MaybeVerifiableRelayResponderChannel::NonVerifiable(c) => {

            }

        };

        // Launch a task to run the channel reactor.

        self.runtime

        Ok(chan)

}

impl<R: Runtime, H: TransportImplHelper> ChanBuilder<R, H>

where

    R: tor_rtcompat::TlsProvider<H::Stream> + Send + Sync,

    H: Send + Sync,

{

    /// Perform the work of `connect_via_transport`, but without enforcing a timeout.

    ///

    /// Return a [`Channel`](tor_proto::channel::Channel) on success.

    #[instrument(skip_all, level = "trace")]

        use tor_rtcompat::tls::CertifiedConn;

        {

            event_sender.lock().expect("Lock poisoned").record_attempt();

        }

        // Before actually doing the connect, we need to validate the channel target based on this

        // build outbound channel type. There are restrictions we need to apply.

        self.validate_target(target)?;

        // 1a. Negotiate the TCP connection or other stream.

        // The returned PeerAddr is the actual address we are connected to.

        let (peer_addr, stream) = self.transport.connect(target).await?;

        // The peer could be a bridge/guard or a relay. We have to shield it right away to avoid

        // leaking the info in the logs but we also want the info for a relay<-> relay.

        let peer_addr = match self.outbound_chan_type() {

            ChannelType::ClientInitiator => MaybeSensitive::sensitive(peer_addr),

            ChannelType::RelayInitiator => MaybeSensitive::not_sensitive(peer_addr),

            _ => return Err(Error::Internal(internal!("Unknown outbound channel type"))),

        };

            move |ioe: io::Error| Error::Io {

        {

            // TODO(nickm): At some point, it would be helpful to the

            // bootstrapping logic if we could distinguish which

            // transport just succeeded.

            event_sender

                .lock()

                .expect("Lock poisoned")

                .record_tcp_success();

        }

        // 1b. Negotiate TLS.

        let hostname = rand_hostname::random_hostname(&mut rand::rng());

        let tls = self

            .tls_connector

            .negotiate_unvalidated(stream, hostname.as_str())

            .await

            .map_err(map_ioe("TLS negotiation"))?;

        let peer_tls_cert = tls

            .peer_certificate()

            .map_err(map_ioe("TLS certs"))?

            // Note: we could skip this "into_owned" if we computed any necessary digest on the

            // certificate earlier.  That would require changing out channel negotiation APIs,

            // though, and might not be worth it.

            .into_owned();

        {

            event_sender

                .lock()

                .expect("Lock poisoned")

                .record_tls_finished();

        }

        // Store this so we can log it in case we don't recognize it.

        let outbound_chan_type = self.outbound_chan_type();

        let chan = match outbound_chan_type {

            ChannelType::ClientInitiator => {

                self.build_client_channel(

                    tls,

                    peer_addr,

                    target,

                    &peer_tls_cert,

                    memquota,

                    event_sender.clone(),

                )

                .await?

            }

            #[cfg(feature = "relay")]

            ChannelType::RelayInitiator => {

                self.build_relay_channel(

                    tls,

                    peer_addr,

                    target,

                    &peer_tls_cert,

                    memquota,

                    event_sender.clone(),

                )

                .await?

            }

            _ => {

                return Err(Error::Internal(internal!(

                    "Unusable channel type for outbound: {outbound_chan_type}",

                )));

            }

        };

        event_sender

            .lock()

            .expect("Lock poisoned")

            .record_handshake_done();

        Ok(chan)

    /// Validate the given `target` as we (a relay) are attempting to connect to another relay.

    #[cfg(feature = "relay")]

    {

        use tor_linkspec::HasRelayIds;

        // Make sure we don't attempt to use a PT method for this relay channel.

            // Return an internal error because the circuit reactor asking us to use a PT is a code

            // flow issue, not a protocol violation.

        // Make sure that all addresses are allowed for an EXTEND. For instance, connecting to a

        // local/private network for security reasons as a it could lead to network

        // scanning by measuring latency between successful connect() and failures.

        //

        // If no addresses, it returns true and thus no error.

        // Connecting to a relay as a relay without key material will fail. This should never

        // happen hence the internal error.

        };

        // Any of our identities match the given target, we are connecting to ourselves, refuse.

        } else {

        }

    /// Validate the given target as in if it is fine to connect to it.

    ///

    ///There are several rules to follow based on the channel outbound type.

    {

        // Make sure that each address has a valid port.

        // Make sure no target address is ourself including the port. A relay is allowed to connect

        // to its IP address but on a different port. We also want to avoid a client bridge to

        // connect back to itself.

        #[cfg(feature = "relay")]

        }

            // This is a client connecting to a relay.

            // This is a relay connecting to a relay.

            #[cfg(feature = "relay")]

            // ChannelType is non_exhaustive but also we only cover outbound channels.

        }

    /// Build a client channel (always initiator).

    ///

    /// This spawns the Reactor and return the [`tor_proto::channel::Channel`].

        // Helper to map protocol level error.

        //

        // We are logging the `target` here as these protocol error happens during the handshake

        // and we need to log the identities that are being tried but it will honor safe logging

        // for the relay <-> relay case which is not ideal but a tradeoff in complexity.

        // Get the client specific channel builder.

            )

                tor_proto::Error::HandshakeCertsExpired { .. } => {

                }

        // Launch a task to run the channel reactor.

    /// Build a relay initiator channel.

    ///

    /// This spawns the Reactor and return the [`tor_proto::channel::Channel`].

    #[cfg(feature = "relay")]

                "Unable to build relay channel without auth material"

            )

                tor_proto::Error::HandshakeCertsExpired { .. } => {

                }

            // Peer address is not sensitive as this is a relay<->relay connection.

        // Launch a task to run the channel reactor.

}

impl crate::mgr::AbstractChannel for tor_proto::channel::Channel {

}

#[cfg(test)]

mod test {

    // @@ begin test lint list maintained by maint/add_warning @@

    #![allow(clippy::bool_assert_comparison)]

    #![allow(clippy::clone_on_copy)]

    #![allow(clippy::dbg_macro)]

    #![allow(clippy::mixed_attributes_style)]

    #![allow(clippy::print_stderr)]

    #![allow(clippy::print_stdout)]

    #![allow(clippy::single_char_pattern)]

    #![allow(clippy::unwrap_used)]

    #![allow(clippy::unchecked_time_subtraction)]

    #![allow(clippy::useless_vec)]

    #![allow(clippy::needless_pass_by_value)]

    //! <!-- @@ end test lint list maintained by maint/add_warning @@ -->

    use super::*;

    use crate::{

        Result,

        mgr::{AbstractChannel, AbstractChannelFactory},

    };

    use futures::StreamExt as _;

    use std::net::SocketAddr;

    use std::time::{Duration, SystemTime};

    use tor_linkspec::{ChannelMethod, HasRelayIds, RelayIdType};

    use tor_llcrypto::pk::ed25519::Ed25519Identity;

    use tor_llcrypto::pk::rsa::RsaIdentity;

    use tor_proto::channel::Channel;

    use tor_proto::memquota::{ChannelAccount, SpecificAccount as _};

    use tor_rtcompat::{NetStreamListener, test_with_one_runtime};

    use tor_rtmock::{io::LocalStream, net::MockNetwork};

    #[allow(deprecated)] // TODO #1885

    use tor_rtmock::MockSleepRuntime;

    // Make sure that the builder can build a real channel.  To test

    // this out, we set up a listener that pretends to have the right

    // IP, fake the current time, and use a canned response from

    // [`testing::msgs`] crate.

    #[test]

    fn build_ok() -> Result<()> {

        use crate::testing::msgs;

        let orport: SocketAddr = msgs::ADDR.parse().unwrap();

        let ed: Ed25519Identity = msgs::ED_ID.into();

        let rsa: RsaIdentity = msgs::RSA_ID.into();

        let client_addr = "192.0.2.17".parse().unwrap();

        let tls_cert = msgs::X509_CERT.into();

        let target = OwnedChanTarget::builder()

            .addrs(vec![orport])

            .method(ChannelMethod::Direct(vec![orport]))

            .ed_identity(ed)

            .rsa_identity(rsa)

            .build()

            .unwrap();

        let now = SystemTime::UNIX_EPOCH + Duration::new(msgs::NOW, 0);

        test_with_one_runtime!(|rt| async move {

            // Stub out the internet so that this connection can work.

            let network = MockNetwork::new();

            // Set up a client runtime with a given IP

            let client_rt = network

                .builder()

                .add_address(client_addr)

                .runtime(rt.clone());

            // Mock the current time too

            #[allow(deprecated)] // TODO #1885

            let client_rt = MockSleepRuntime::new(client_rt);

            // Set up a relay runtime with a different IP

            let relay_rt = network

                .builder()

                .add_address(orport.ip())

                .runtime(rt.clone());

            // open a fake TLS listener and be ready to handle a request.

            let lis = relay_rt.mock_net().listen_tls(&orport, tls_cert).unwrap();

            // Tell the client to believe in a different timestamp.

            client_rt.jump_to(now);

            // Create the channel builder that we want to test.

            let transport = crate::transport::DefaultTransport::new(client_rt.clone(), None);

            let builder = ChanBuilder::new_client(client_rt, transport);

            let (r1, r2): (Result<Arc<Channel>>, Result<LocalStream>) = futures::join!(

                async {

                    // client-side: build a channel!

                    builder

                        .build_channel(

                            &target,

                            BootstrapReporter::fake(),

                            ChannelAccount::new_noop(),

                        )

                        .await

                },

                async {

                    // relay-side: accept the channel

                    // (and pretend to know what we're doing).

                    let (mut con, addr) = lis

                        .incoming()

                        .next()

                        .await

                        .expect("Closed?")

                        .expect("accept failed");

                    assert_eq!(client_addr, addr.ip());

                    crate::testing::answer_channel_req(&mut con)

                        .await

                        .expect("answer failed");

                    Ok(con)

                }

            );

            let chan = r1.unwrap();

            assert_eq!(chan.identity(RelayIdType::Ed25519), Some((&ed).into()));

            assert!(chan.is_usable());

            // In theory, time could pass here, so we can't just use

            // "assert_eq!(dur_unused, dur_unused2)".

            let dur_unused = Channel::duration_unused(&chan);

            let dur_unused_2 = AbstractChannel::duration_unused(chan.as_ref());

            let dur_unused_3 = Channel::duration_unused(&chan);

            assert!(dur_unused.unwrap() <= dur_unused_2.unwrap());

            assert!(dur_unused_2.unwrap() <= dur_unused_3.unwrap());

            r2.unwrap();

            Ok(())

        })

    }

    // TODO: Write tests for timeout logic, once there is smarter logic.

}