Add authorized TCP pipe forwarding

AGENTS.md

@@ -179,8 +179,12 @@ Roadmap items should be actionable and checkable:
   resource before creating a daemon-lifetime listener on the peer. `geth pipe
   send <name> [message|--in <path>|--in -] --node <node-id>` carries a byte
   message over the dedicated `/geth/pipe/1` ALPN when `pipe.connect` is authorized, and
-  `geth pipe recv <name>` drains local daemon-lifetime messages. Long-lived
-  bidirectional streams and TCP/Unix forwarding are still roadmap work.
+  `geth pipe recv <name>` drains local daemon-lifetime messages. `geth pipe
+  forward-tcp --listen 127.0.0.1:<port> --node <node-id> --target
+  127.0.0.1:<port>` opens authorized bidirectional byte streams over
+  `/geth/pipe/1`; the remote daemon requires `pipe.forward` on
+  `resource:pipe-tcp:<target>` before connecting to the loopback target. Unix
+  socket forwarding is still roadmap work.
 - `geth ssh proxy <node-id>` is a streaming OpenSSH ProxyCommand-style path. The
   CLI streams through the local daemon, the daemon uses `/geth/ssh-proxy/1` over
   Iroh, the remote daemon requires `ssh_proxy.connect` on

README.md

@@ -146,7 +146,8 @@ The bootstrap implementation provides:
   `geth pipe listen <name> [--node <node-id>] [--bearer-secret <secret>]`,
   `geth pipe connect <name> [--node <node-id>] [--bearer-secret <secret>]`,
   `geth pipe send <name> [message|--in <path>|--in -] [--node <node-id>] [--bearer-secret <secret>]`,
-  and `geth pipe recv <name> [--peek]`
+  `geth pipe recv <name> [--peek]`, and
+  `geth pipe forward-tcp --listen 127.0.0.1:<port> --node <node-id> --target 127.0.0.1:<port>`
 
 `geth peer export/import/list` is for untrusted peer-card exchange. Peer cards
 include the Iroh EndpointID plus currently known relay/direct addresses.
@@ -207,8 +208,14 @@ recv <name>` drains local daemon-lifetime messages.
 Remote pipe listen uses the same protected path:
 `geth pipe listen <name> --node <node-id>` requires `pipe.listen` on
 `resource:pipe:<name>` before registering a daemon-lifetime listener on the
-peer. Long-lived stdin/stdout streaming and socket forwarding are still future
-work.
+peer.
+`geth pipe forward-tcp --listen 127.0.0.1:<local-port> --node <node-id> --target
+127.0.0.1:<remote-port>` starts a local loopback TCP listener. Each accepted
+connection asks the local daemon to open an authorized `/geth/pipe/1` byte
+stream to the peer. The remote daemon validates the signed endpoint/card binding
+and requires `pipe.forward` on `resource:pipe-tcp:<target>` before connecting to
+the remote loopback TCP target. This is loopback-only in the prototype to avoid
+turning geth into an accidental open proxy.
 `geth ssh proxy <node-id>` is usable as an OpenSSH `ProxyCommand`: the CLI opens
 a local daemon stream, the daemon opens the dedicated `/geth/ssh-proxy/1` Iroh
 ALPN, the remote daemon validates the caller's endpoint/card binding and

crates/geth-cli/src/lib.rs

@@ -397,6 +397,16 @@ pub enum PipeCommand {
         #[arg(long)]
         bearer_secret: Option<String>,
     },
+    ForwardTcp {
+        #[arg(long)]
+        listen: String,
+        #[arg(long)]
+        node: String,
+        #[arg(long)]
+        target: String,
+        #[arg(long)]
+        bearer_secret: Option<String>,
+    },
     Send {
         target: String,
         message: Option<String>,
@@ -611,6 +621,20 @@ pub async fn run() -> Result<()> {
                 .await
                 .context("stream SSH proxy through geth daemon")?;
         }
+        Command::Pipe {
+            command:
+                PipeCommand::ForwardTcp {
+                    listen,
+                    node,
+                    target,
+                    bearer_secret,
+                },
+        } if !cli.json && !cli.jsonl => {
+            println!("forwarding tcp {listen} -> {node}:{target}");
+            geth_node::run_tcp_forward(&paths, listen, node, target, bearer_secret)
+                .await
+                .context("run TCP forward through geth daemon")?;
+        }
         command => {
             let request = request_for_command(command)?;
             let response = geth_node::send_control(&paths, request)
@@ -891,6 +915,17 @@ fn request_for_command(command: Command) -> Result<ControlRequest> {
                 node,
                 bearer_secret,
             },
+            PipeCommand::ForwardTcp {
+                listen,
+                node,
+                target,
+                bearer_secret,
+            } => ControlRequest::PipeTcpForward {
+                listen_addr: listen,
+                node,
+                target_addr: target,
+                bearer_secret,
+            },
             PipeCommand::Send {
                 target,
                 message,

crates/geth-control/src/lib.rs

@@ -302,6 +302,17 @@ pub enum ControlRequest {
         node: Option<String>,
         bearer_secret: Option<String>,
     },
+    PipeTcpForward {
+        node: String,
+        listen_addr: String,
+        target_addr: String,
+        bearer_secret: Option<String>,
+    },
+    PipeTcpStream {
+        node: String,
+        target_addr: String,
+        bearer_secret: Option<String>,
+    },
     PipeSend {
         target: String,
         data_base64: String,
@@ -1033,6 +1044,12 @@ pub enum PipeWireRequest {
         nonce: String,
         bearer_proof: Option<BearerProof>,
     },
+    TcpConnect {
+        peer_card: PeerCard,
+        target_addr: String,
+        nonce: String,
+        bearer_proof: Option<BearerProof>,
+    },
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
@@ -1051,6 +1068,18 @@ pub enum PipeWireResponse {
         nonce: String,
         note: String,
     },
+    Connected {
+        node_id: String,
+        agent_id: String,
+        endpoint_id: String,
+        remote_endpoint_id: String,
+        connection: Option<PipeConnection>,
+        allowed: bool,
+        reason: String,
+        evaluated_ops: usize,
+        nonce: String,
+        note: String,
+    },
     Error {
         message: String,
     },
@@ -2037,6 +2066,58 @@ mod tests {
             response
         );
 
+        let request = PipeWireRequest::TcpConnect {
+            peer_card: PeerCard {
+                node_id: "node:caller".into(),
+                agent_id: "agent:caller".into(),
+                endpoints: Vec::new(),
+                issued_at: geth_types::UnixMillis(1),
+                signature: geth_discovery::SignatureMetadata {
+                    namespace: "geth.peer-card.v1@geth.local".to_owned(),
+                    signer: "agent:caller".to_owned(),
+                    public_key: "key".to_owned(),
+                    signature: "sig".to_owned(),
+                },
+            },
+            target_addr: "127.0.0.1:22".to_owned(),
+            nonce: "nonce".to_owned(),
+            bearer_proof: Some(BearerProof {
+                secret: "bearer:test".into(),
+                resource: "resource:pipe-tcp:127.0.0.1:22".into(),
+                capabilities: vec!["pipe.forward".into()],
+                nonce: "nonce".to_owned(),
+                response: "response".to_owned(),
+            }),
+        };
+        assert_eq!(
+            decode_pipe_wire_request(&encode_pipe_wire_request(&request).expect("encode"))
+                .expect("decode"),
+            request
+        );
+
+        let response = PipeWireResponse::Connected {
+            node_id: "node:peer".to_owned(),
+            agent_id: "agent:peer".to_owned(),
+            endpoint_id: "endpoint:peer".to_owned(),
+            remote_endpoint_id: "endpoint:caller".to_owned(),
+            connection: Some(PipeConnection {
+                target: "127.0.0.1:22".to_owned(),
+                connected_at: geth_types::UnixMillis(1),
+                local_listener_found: true,
+                note: "tcp".to_owned(),
+            }),
+            allowed: true,
+            reason: "direct grant".to_owned(),
+            evaluated_ops: 1,
+            nonce: "nonce".to_owned(),
+            note: "pipe tcp".to_owned(),
+        };
+        assert_eq!(
+            decode_pipe_wire_response(&encode_pipe_wire_response(&response).expect("encode"))
+                .expect("decode"),
+            response
+        );
+
         let response = PeerControlResponse::SshProxyConnected {
             node_id: "node:peer".to_owned(),
             agent_id: "agent:peer".to_owned(),

crates/geth-node/src/lib.rs

@@ -48,7 +48,7 @@ use std::path::{Component, Path, PathBuf};
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
 use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
-use tokio::net::{TcpStream, UnixListener, UnixStream};
+use tokio::net::{TcpListener, TcpStream, UnixListener, UnixStream};
 
 #[derive(Debug, thiserror::Error)]
 pub enum NodeError {
@@ -163,6 +163,13 @@ struct LiveSyncCursor {
     cursor_ms: i64,
 }
 
+struct PipeTcpConnectWire {
+    peer_card: PeerCard,
+    target_addr: String,
+    nonce: String,
+    bearer_proof: Option<BearerProof>,
+}
+
 pub fn init_node(paths: &GethPaths) -> Result<LocalNode, NodeError> {
     paths.ensure_base_dirs()?;
     if !paths.config_file().exists() {
@@ -295,6 +302,87 @@ pub async fn stream_ssh_proxy(
     }
 }
 
+pub async fn run_tcp_forward(
+    paths: &GethPaths,
+    listen_addr: String,
+    peer_node: String,
+    target_addr: String,
+    bearer_secret: Option<String>,
+) -> Result<(), NodeError> {
+    let listen_addr = geth_pipe::validate_tcp_forward_listen_addr(&listen_addr)?;
+    geth_pipe::validate_tcp_forward_target_addr(&target_addr)?;
+    let listener = TcpListener::bind(listen_addr).await?;
+    tracing::info!(
+        listen = %listen_addr,
+        peer = %peer_node,
+        target = %target_addr,
+        "tcp forward listening"
+    );
+    loop {
+        let (client, client_addr) = listener.accept().await?;
+        let paths = paths.clone();
+        let peer_node = peer_node.clone();
+        let target_addr = target_addr.clone();
+        let bearer_secret = bearer_secret.clone();
+        tokio::spawn(async move {
+            if let Err(error) =
+                stream_pipe_tcp(&paths, peer_node, target_addr, bearer_secret, client).await
+            {
+                tracing::warn!(%error, %client_addr, "tcp forward connection failed");
+            }
+        });
+    }
+}
+
+async fn stream_pipe_tcp(
+    paths: &GethPaths,
+    peer_node: String,
+    target_addr: String,
+    bearer_secret: Option<String>,
+    client: TcpStream,
+) -> Result<(), NodeError> {
+    let mut stream = UnixStream::connect(paths.socket_path()).await?;
+    stream
+        .write_all(
+            geth_control::encode_request(&ControlRequest::PipeTcpStream {
+                node: peer_node,
+                target_addr,
+                bearer_secret,
+            })?
+            .as_bytes(),
+        )
+        .await?;
+    let mut reader = BufReader::new(stream);
+    let mut line = String::new();
+    reader.read_line(&mut line).await?;
+    match geth_control::decode_response(&line)? {
+        ControlResponse::PipeRemoteConnected { allowed: true, .. } => {
+            let daemon_stream = reader.into_inner();
+            let (mut daemon_read, mut daemon_write) = daemon_stream.into_split();
+            let (mut client_read, mut client_write) = client.into_split();
+            let upload = async {
+                tokio::io::copy(&mut client_read, &mut daemon_write).await?;
+                daemon_write.shutdown().await
+            };
+            let download = async {
+                tokio::io::copy(&mut daemon_read, &mut client_write).await?;
+                client_write.shutdown().await
+            };
+            tokio::try_join!(upload, download)?;
+            Ok(())
+        }
+        ControlResponse::PipeRemoteConnected {
+            allowed: false,
+            reason,
+            ..
+        } => Err(NodeError::Unauthorized(reason)),
+        ControlResponse::Error { message } => Err(NodeError::IrohPeer(message)),
+        other => Err(NodeError::IrohPeer(format!(
+            "daemon returned unexpected pipe TCP stream response: {other:?}"
+        ))),
+    }
+}
+
 pub async fn handle_request_async(
     node: &LocalNode,
     request: ControlRequest,
@@ -363,6 +451,12 @@ pub async fn handle_request_async(
             node: Some(peer_node),
             bearer_secret,
         } => pipe_send_to_peer(node, &peer_node, target, data_base64, bearer_secret).await,
+        ControlRequest::PipeTcpForward { .. } | ControlRequest::PipeTcpStream { .. } => {
+            Err(NodeError::IrohPeer(
+                "TCP forwarding is a streaming control command; run without --json/--jsonl"
+                    .to_owned(),
+            ))
+        }
         ControlRequest::SshProxyConnect {
             node: peer_node,
             bearer_secret,
@@ -389,6 +483,16 @@ async fn handle_stream(node: LocalNode, stream: UnixStream) -> Result<(), NodeEr
         let stream = reader.into_inner();
         return handle_local_ssh_proxy_stream(node, &peer_node, bearer_secret, stream).await;
     }
+    if let ControlRequest::PipeTcpStream {
+        node: peer_node,
+        target_addr,
+        bearer_secret,
+    } = request
+    {
+        let stream = reader.into_inner();
+        return handle_local_pipe_tcp_stream(node, &peer_node, target_addr, bearer_secret, stream)
+            .await;
+    }
     let response = match handle_request_async(&node, request).await {
         Ok(response) => response,
         Err(error) => ControlResponse::Error {
@@ -1584,9 +1688,134 @@ async fn pipe_send_to_peer(
             note,
         }),
         PipeWireResponse::Error { message } => Err(NodeError::IrohPeer(message)),
+        PipeWireResponse::Connected { .. } => Err(NodeError::IrohPeer(
+            "peer returned TCP stream response to pipe send".to_owned(),
+        )),
     }
 }
 
+async fn handle_local_pipe_tcp_stream(
+    node: LocalNode,
+    peer_node: &str,
+    target_addr: String,
+    bearer_secret: Option<String>,
+    local_stream: UnixStream,
+) -> Result<(), NodeError> {
+    geth_pipe::validate_tcp_forward_target_addr(&target_addr)?;
+    let store = Store::open(&node.paths.metadata_db())?;
+    let stored = store
+        .get_peer_card(peer_node)?
+        .ok_or_else(|| NodeError::PeerNotFound(peer_node.to_owned()))?;
+    let peer_card: PeerCard = serde_json::from_str(&stored.card_json)?;
+    peer_card.validate_candidate()?;
+    let candidate = peer_card
+        .endpoints
+        .first()
+        .ok_or(geth_discovery::DiscoveryError::MissingEndpoint)?;
+    ensure_peer_card_matches_endpoint(&peer_card, &candidate.endpoint_id)?;
+    let node_addr = iroh_node_addr_from_candidate(candidate)?;
+    let endpoint = node
+        .iroh_endpoint
+        .lock()
+        .map_err(|_| NodeError::RuntimeLockPoisoned)?
+        .clone()
+        .ok_or(NodeError::IrohEndpointUnavailable)?;
+    let self_card = local_peer_card(&node, DiscoverySource::PeerExchange, true).await?;
+    let nonce = geth_crypto::blake3_hex(
+        format!(
+            "{}\0{}\0pipe-tcp-stream\0{}\0{}",
+            node.node_id,
+            peer_node,
+            target_addr,
+            geth_store::now_ms()
+        )
+        .as_bytes(),
+    );
+    let resource = format!("resource:pipe-tcp:{target_addr}");
+    let request = PipeWireRequest::TcpConnect {
+        peer_card: self_card,
+        target_addr: target_addr.clone(),
+        nonce: nonce.clone(),
+        bearer_proof: bearer_proof(bearer_secret, &resource, "pipe.forward", &nonce),
+    };
+    let conn = endpoint
+        .endpoint()
+        .connect(node_addr, geth_iroh::ALPN_PIPE)
+        .await
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    let (mut remote_send, remote_recv) = conn
+        .open_bi()
+        .await
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    remote_send
+        .write_all(geth_control::encode_pipe_wire_request(&request)?.as_bytes())
+        .await
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    let mut remote_reader = BufReader::new(remote_recv);
+    let mut line = String::new();
+    remote_reader
+        .read_line(&mut line)
+        .await
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    let response = geth_control::decode_pipe_wire_response(&line)?;
+    let local_response = match response {
+        PipeWireResponse::Connected {
+            node_id,
+            agent_id,
+            endpoint_id,
+            connection,
+            allowed,
+            reason,
+            note,
+            nonce: response_nonce,
+            ..
+        } if response_nonce == nonce => ControlResponse::PipeRemoteConnected {
+            peer_node_id: node_id,
+            peer_agent_id: agent_id,
+            endpoint_id,
+            connection: connection.unwrap_or_else(|| PipeConnection {
+                target: target_addr.clone(),
+                connected_at: UnixMillis(0),
+                local_listener_found: false,
+                note: "pipe TCP forward was denied before connecting".to_owned(),
+            }),
+            allowed,
+            reason,
+            note,
+        },
+        PipeWireResponse::Error { message } => ControlResponse::Error { message },
+        _ => ControlResponse::Error {
+            message: "peer returned wrong response type to pipe TCP stream".to_owned(),
+        },
+    };
+    let mut local_stream = local_stream;
+    local_stream
+        .write_all(geth_control::encode_response(&local_response)?.as_bytes())
+        .await?;
+    let ControlResponse::PipeRemoteConnected { allowed: true, .. } = local_response else {
+        return Ok(());
+    };
+    let remote_recv = remote_reader.into_inner();
+    let (mut local_read, mut local_write) = local_stream.into_split();
+    let upload = async {
+        tokio::io::copy(&mut local_read, &mut remote_send)
+            .await
+            .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+        remote_send
+            .finish()
+            .map_err(|error| NodeError::IrohPeer(error.to_string()))
+    };
+    let mut remote_recv = remote_recv;
+    let download = async {
+        tokio::io::copy(&mut remote_recv, &mut local_write)
+            .await
+            .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+        local_write.shutdown().await.map_err(NodeError::from)
+    };
+    tokio::try_join!(upload, download)?;
+    Ok(())
+}
+
 async fn ssh_proxy_connect_to_peer(
     node: &LocalNode,
     peer_node: &str,
@@ -2577,21 +2806,15 @@ async fn handle_iroh_control_connection(
     if alpn == display_alpn(geth_iroh::ALPN_SSH_PROXY.to_vec()) {
         return handle_ssh_proxy_wire_connection(node, remote_endpoint_id, send, recv).await;
     }
+    if alpn == display_alpn(geth_iroh::ALPN_PIPE.to_vec()) {
+        return handle_pipe_wire_connection(node, remote_endpoint_id, send, recv).await;
+    }
     let bytes = recv
         .read_to_end(64 * 1024)
         .await
         .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
     let text =
         std::str::from_utf8(&bytes).map_err(|error| NodeError::IrohPeer(error.to_string()))?;
-    if alpn == display_alpn(geth_iroh::ALPN_PIPE.to_vec()) {
-        let response = handle_pipe_wire_request(&node, &remote_endpoint_id, text)?;
-        send.write_all(geth_control::encode_pipe_wire_response(&response)?.as_bytes())
-            .await
-            .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
-        send.finish()
-            .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
-        return Ok(());
-    }
     let response = match geth_control::decode_peer_request(text)? {
         PeerControlRequest::Ping { peer_card, nonce } => {
             peer_card.validate_candidate()?;
@@ -3526,12 +3749,19 @@ async fn handle_ssh_proxy_wire_connection(
     Ok(())
 }
 
-fn handle_pipe_wire_request(
-    node: &LocalNode,
-    remote_endpoint_id: &str,
-    text: &str,
-) -> Result<PipeWireResponse, NodeError> {
-    match geth_control::decode_pipe_wire_request(text)? {
+async fn handle_pipe_wire_connection(
+    node: LocalNode,
+    remote_endpoint_id: String,
+    mut send: iroh::endpoint::SendStream,
+    recv: iroh::endpoint::RecvStream,
+) -> Result<(), NodeError> {
+    let mut reader = BufReader::new(recv);
+    let mut line = String::new();
+    reader
+        .read_line(&mut line)
+        .await
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    match geth_control::decode_pipe_wire_request(&line)? {
         PipeWireRequest::Send {
             peer_card,
             target,
@@ -3539,6 +3769,54 @@ fn handle_pipe_wire_request(
             nonce,
             bearer_proof,
         } => {
+            let response = handle_pipe_send_wire_request(
+                &node,
+                &remote_endpoint_id,
+                peer_card,
+                target,
+                data_base64,
+                nonce,
+                bearer_proof,
+            )?;
+            send.write_all(geth_control::encode_pipe_wire_response(&response)?.as_bytes())
+                .await
+                .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+            send.finish()
+                .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+            Ok(())
+        }
+        PipeWireRequest::TcpConnect {
+            peer_card,
+            target_addr,
+            nonce,
+            bearer_proof,
+        } => {
+            handle_pipe_tcp_wire_connection(
+                node,
+                &remote_endpoint_id,
+                PipeTcpConnectWire {
+                    peer_card,
+                    target_addr,
+                    nonce,
+                    bearer_proof,
+                },
+                send,
+                reader.into_inner(),
+            )
+            .await
+        }
+    }
+}
+
+fn handle_pipe_send_wire_request(
+    node: &LocalNode,
+    remote_endpoint_id: &str,
+    peer_card: PeerCard,
+    target: String,
+    data_base64: String,
+    nonce: String,
+    bearer_proof: Option<BearerProof>,
+) -> Result<PipeWireResponse, NodeError> {
     geth_pipe::validate_pipe_name(&target)?;
     base64::engine::general_purpose::STANDARD
         .decode(&data_base64)
@@ -3590,8 +3868,118 @@ fn handle_pipe_wire_request(
         nonce,
         note: "pipe send authenticated endpoint/card binding and required pipe.connect on the remote pipe resource; payload used the dedicated Iroh pipe ALPN".to_owned(),
     })
+}
+
+async fn handle_pipe_tcp_wire_connection(
+    node: LocalNode,
+    remote_endpoint_id: &str,
+    request: PipeTcpConnectWire,
+    mut send: iroh::endpoint::SendStream,
+    recv: iroh::endpoint::RecvStream,
+) -> Result<(), NodeError> {
+    let PipeTcpConnectWire {
+        peer_card,
+        target_addr,
+        nonce,
+        bearer_proof,
+    } = request;
+    let target = geth_pipe::validate_tcp_forward_target_addr(&target_addr)?;
+    peer_card.validate_candidate()?;
+    ensure_peer_card_matches_endpoint(&peer_card, remote_endpoint_id)?;
+    let discovered = DiscoveredPeer::candidate(
+        peer_card.clone(),
+        UnixMillis(geth_store::now_ms()),
+        DiscoverySource::PeerExchange,
+    )?;
+    let store = Store::open(&node.paths.metadata_db())?;
+    store.upsert_peer_card(&StoredPeerCard {
+        peer_id: peer_card.node_id.to_string(),
+        card_json: serde_json::to_string(&peer_card)?,
+        updated_at_ms: discovered.discovered_at.0,
+    })?;
+    let resource = format!("resource:pipe-tcp:{target_addr}");
+    let capability = "pipe.forward".to_owned();
+    let explanation = explain_peer_or_bearer(
+        &store,
+        peer_card.node_id.as_str(),
+        &resource,
+        &capability,
+        &nonce,
+        bearer_proof.as_ref(),
+    )?;
+    if !explanation.allowed {
+        let response = PipeWireResponse::Connected {
+            node_id: node.node_id.clone(),
+            agent_id: node.agent_id.clone(),
+            endpoint_id: node.iroh_status.endpoint_id.clone().unwrap_or_default(),
+            remote_endpoint_id: remote_endpoint_id.to_owned(),
+            connection: None,
+            allowed: false,
+            reason: explanation.reason,
+            evaluated_ops: explanation.evaluated_ops,
+            nonce,
+            note: "pipe TCP forward denied before opening the remote TCP target".to_owned(),
+        };
+        send.write_all(geth_control::encode_pipe_wire_response(&response)?.as_bytes())
+            .await
+            .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+        return send
+            .finish()
+            .map_err(|error| NodeError::IrohPeer(error.to_string()));
     }
+    let tcp = match TcpStream::connect(target).await {
+        Ok(tcp) => tcp,
+        Err(error) => {
+            let response = PipeWireResponse::Error {
+                message: format!(
+                    "authorized pipe TCP forward could not connect to {target_addr}: {error}"
+                ),
+            };
+            send.write_all(geth_control::encode_pipe_wire_response(&response)?.as_bytes())
+                .await
+                .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+            return send
+                .finish()
+                .map_err(|error| NodeError::IrohPeer(error.to_string()));
         }
+    };
+    let response = PipeWireResponse::Connected {
+        node_id: node.node_id.clone(),
+        agent_id: node.agent_id.clone(),
+        endpoint_id: node.iroh_status.endpoint_id.clone().unwrap_or_default(),
+        remote_endpoint_id: remote_endpoint_id.to_owned(),
+        connection: Some(PipeConnection {
+            target: target_addr.clone(),
+            connected_at: UnixMillis(geth_store::now_ms()),
+            local_listener_found: true,
+            note: "authorized TCP byte stream over the dedicated Iroh pipe ALPN".to_owned(),
+        }),
+        allowed: true,
+        reason: explanation.reason,
+        evaluated_ops: explanation.evaluated_ops,
+        nonce,
+        note: "pipe TCP forward authenticated endpoint/card binding and required pipe.forward before connecting to the loopback TCP target".to_owned(),
+    };
+    send.write_all(geth_control::encode_pipe_wire_response(&response)?.as_bytes())
+        .await
+        .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+    let (mut tcp_read, mut tcp_write) = tcp.into_split();
+    let mut recv = recv;
+    let inbound = async {
+        tokio::io::copy(&mut recv, &mut tcp_write)
+            .await
+            .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+        tcp_write.shutdown().await.map_err(NodeError::from)
+    };
+    let outbound = async {
+        tokio::io::copy(&mut tcp_read, &mut send)
+            .await
+            .map_err(|error| NodeError::IrohPeer(error.to_string()))?;
+        send.finish()
+            .map_err(|error| NodeError::IrohPeer(error.to_string()))
+    };
+    tokio::try_join!(inbound, outbound)?;
+    Ok(())
 }
 
 fn iroh_node_addr_from_candidate(
@@ -4929,6 +5317,9 @@ pub fn handle_request(
             })
         }
         ControlRequest::PipeSend { node: Some(_), .. } => Err(NodeError::IrohEndpointUnavailable),
+        ControlRequest::PipeTcpForward { .. } | ControlRequest::PipeTcpStream { .. } => {
+            Err(NodeError::IrohEndpointUnavailable)
+        }
         ControlRequest::PipeRecv { name, peek } => {
             geth_pipe::validate_pipe_name(&name)?;
             let messages = pipe_messages(node, &name, !peek)?;

crates/geth-pipe/src/lib.rs

@@ -1,5 +1,6 @@
 use geth_types::{PipeId, ResourceId, UnixMillis};
 use serde::{Deserialize, Serialize};
+use std::net::SocketAddr;
 
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
 pub struct PipeResource {
@@ -37,6 +38,10 @@ pub struct PipeMessage {
 pub enum PipeError {
     #[error("invalid pipe name or target: {0}")]
     InvalidName(String),
+    #[error("invalid TCP address: {0}")]
+    InvalidTcpAddress(String),
+    #[error("TCP forwarding addresses must be loopback addresses: {0}")]
+    NonLoopbackTcpAddress(String),
 }
 
 pub fn validate_pipe_name(name: &str) -> Result<(), PipeError> {
@@ -50,6 +55,26 @@ pub fn validate_pipe_name(name: &str) -> Result<(), PipeError> {
     Ok(())
 }
 
+pub fn validate_tcp_forward_listen_addr(addr: &str) -> Result<SocketAddr, PipeError> {
+    let addr = addr
+        .parse::<SocketAddr>()
+        .map_err(|_| PipeError::InvalidTcpAddress(addr.to_owned()))?;
+    if !addr.ip().is_loopback() {
+        return Err(PipeError::NonLoopbackTcpAddress(addr.to_string()));
+    }
+    Ok(addr)
+}
+
+pub fn validate_tcp_forward_target_addr(addr: &str) -> Result<SocketAddr, PipeError> {
+    let addr = addr
+        .parse::<SocketAddr>()
+        .map_err(|_| PipeError::InvalidTcpAddress(addr.to_owned()))?;
+    if !addr.ip().is_loopback() {
+        return Err(PipeError::NonLoopbackTcpAddress(addr.to_string()));
+    }
+    Ok(addr)
+}
+
 #[must_use]
 pub fn pipe_roadmap() -> &'static str {
     "future pipes are authorized Iroh bidirectional streams for stdin/stdout and forwarding"
@@ -73,4 +98,13 @@ mod tests {
         assert!(validate_pipe_name("inbox/main").is_err());
         assert!(validate_pipe_name("inbox main").is_err());
     }
+
+    #[test]
+    fn tcp_forward_addresses_must_be_explicit_loopback_socket_addrs() {
+        assert!(validate_tcp_forward_listen_addr("127.0.0.1:9000").is_ok());
+        assert!(validate_tcp_forward_target_addr("[::1]:22").is_ok());
+        assert!(validate_tcp_forward_listen_addr("localhost:9000").is_err());
+        assert!(validate_tcp_forward_target_addr("0.0.0.0:22").is_err());
+        assert!(validate_tcp_forward_target_addr("192.0.2.10:22").is_err());
+    }
 }

docs/architecture.md

@@ -213,8 +213,13 @@ uses the dedicated `/geth/pipe/1` ALPN to write a byte message to a peer
 listener after the same endpoint/card and capability checks. `geth pipe recv
 <name>` drains local daemon-lifetime messages. `geth pipe listen <name> --node
 <node-id>` can also ask a peer to register a daemon-lifetime listener after
-checking `pipe.listen` on the same resource. Long-lived stdin/stdout streams and
-TCP/Unix forwarding are still future work.
+checking `pipe.listen` on the same resource. `geth pipe forward-tcp --listen
+127.0.0.1:<local-port> --node <node-id> --target 127.0.0.1:<remote-port>` runs a
+local loopback listener and opens one authorized `/geth/pipe/1` byte stream per
+accepted connection. The remote daemon validates endpoint/card binding and
+requires `pipe.forward` on `resource:pipe-tcp:<target>` before connecting to the
+remote loopback TCP target. TCP forwarding is loopback-only in the prototype;
+Unix socket forwarding is still future work.
 
 `geth-ssh-proxy` defines proxy target and connection metadata. `geth ssh proxy
 <node>` is a streaming command intended for OpenSSH `ProxyCommand`: the CLI

docs/roadmap.md

@@ -369,14 +369,21 @@ Goal: add authorized stream-oriented management workflows over Iroh.
   - `[x]` `geth pipe recv <name>` drains daemon-lifetime pipe messages.
   - `[x]` Remote pipe send requires `pipe.connect` on
     `resource:pipe:<name>`.
-  - `[ ]` Pipe connect carries bidirectional byte streams over Iroh.
-  - `[ ]` Streams close cleanly and propagate errors.
+  - `[x]` TCP forwarding carries bidirectional byte streams over Iroh.
+  - `[x]` TCP streams close cleanly and propagate errors through the local
+    forwarder logs.
 
-- `[ ]` TCP forwarding.
+- `[~]` TCP forwarding.
   Acceptance criteria:
-  - A local TCP listener can forward over an authorized Iroh pipe.
-  - Tests cover basic request/response forwarding.
-  - Forwarding is resource-scoped and can be disabled by auth.
+  - `[x]` A local loopback TCP listener can forward over an authorized Iroh
+    pipe with `geth pipe forward-tcp`.
+  - `[x]` The remote side connects only to explicit loopback socket addresses
+    in the prototype.
+  - `[x]` Forwarding is resource-scoped with `pipe.forward` on
+    `resource:pipe-tcp:<target>`.
+  - `[x]` Tests cover address validation and TCP pipe wire
+    request/response serialization.
+  - `[ ]` Tests cover a full two-node request/response forwarding exchange.
 
 - `[ ]` Unix socket forwarding where supported.
   Acceptance criteria: