client channel handling changes

Author: Eugeny

russh/src/client/encrypted.rs

@@ -761,13 +761,15 @@ impl Session {
                     match &msg.typ {
                         ChannelType::Session => {
                             confirm();
-                            client.server_channel_open_session(id, self).await?
+                            let channel = self.accept_server_initiated_channel(id, &msg);
+                            client.server_channel_open_session(channel, self).await?
                         }
                         ChannelType::DirectTcpip(d) => {
                             confirm();
+                            let channel = self.accept_server_initiated_channel(id, &msg);
                             client
                                 .server_channel_open_direct_tcpip(
-                                    id,
+                                    channel,
                                     &d.host_to_connect,
                                     d.port_to_connect,
                                     &d.originator_address,
@@ -818,11 +820,16 @@ impl Session {
                         }
                         ChannelType::AgentForward => {
                             confirm();
-                            client.server_channel_open_agent_forward(id, self).await?
+                            let channel = self.accept_server_initiated_channel(id, &msg);
+                            client
+                                .server_channel_open_agent_forward(channel, self)
+                                .await?
                         }
                         ChannelType::Unknown { typ } => {
-                            if client.server_channel_handle_unknown(id, typ) {
+                            if client.should_accept_unknown_server_channel(id, typ).await {
                                 confirm();
+                                let channel = self.accept_server_initiated_channel(id, &msg);
+                                client.server_channel_open_unknown(channel, self).await?;
                             } else {
                                 debug!("unknown channel type: {}", String::from_utf8_lossy(typ));
                                 msg.unknown_type(&mut enc.write);

russh/src/client/mod.rs

@@ -1633,25 +1633,40 @@ pub trait Handler: Sized + Send {
     #[allow(unused_variables)]
     async fn server_channel_open_agent_forward(
         &mut self,
-        channel: ChannelId,
+        channel: Channel<Msg>,
         session: &mut Session,
     ) -> Result<(), Self::Error> {
         Ok(())
     }
 
-    /// Called when the server gets an unknown channel. It may return `true`,
-    /// if the channel of unknown type should be handled. If it returns `false`,
-    /// the channel will not be created and an error will be sent to the server.
+    /// Called when the server attempts to open a channel of unknown type. It may return `true`,
+    /// if the channel of unknown type should be accepted. In this case,
+    /// [Handler::server_channel_open_unknown] will be called soon after. If it returns `false`,
+    /// the channel will not be created and a rejection message will be sent to the server.
     #[allow(unused_variables)]
-    fn server_channel_handle_unknown(&self, channel: ChannelId, channel_type: &[u8]) -> bool {
+    async fn should_accept_unknown_server_channel(
+        &mut self,
+        id: ChannelId,
+        channel_type: &[u8],
+    ) -> bool {
         false
     }
 
+    /// Called when the server opens an unknown channel.
+    #[allow(unused_variables)]
+    async fn server_channel_open_unknown(
+        &mut self,
+        channel: Channel<Msg>,
+        session: &mut Session,
+    ) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
     /// Called when the server opens a session channel.
     #[allow(unused_variables)]
     async fn server_channel_open_session(
         &mut self,
-        channel: ChannelId,
+        channel: Channel<Msg>,
         session: &mut Session,
     ) -> Result<(), Self::Error> {
         Ok(())
@@ -1661,7 +1676,7 @@ pub trait Handler: Sized + Send {
     #[allow(unused_variables)]
     async fn server_channel_open_direct_tcpip(
         &mut self,
-        channel: ChannelId,
+        channel: Channel<Msg>,
         host_to_connect: &str,
         port_to_connect: u32,
         originator_address: &str,