Citrix – An error occurred when processing incoming CGP downstream data

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The following error message is displayed in the Application Event Log:

Event ID: 103 – “An error occurred when processing incoming CGP downstream data.”
Source: Reliability Server

Citrix - An error occurred when processing incoming CGP downstream data

Background

These error messages occur even if there are no sessions on the server. It was noticed that these error messages appeared after the Hotfix Rollup Pack 1 for Citrix Presentation Server 4.5 was installed. The errors remain even if Hotfix Rollup Pack 1 is removed.

Note: The problem has also been observed on XenApp 6.5.

The same error messages are displayed in the XTE log file. Following is the sample of the error messages in the XTE log file:

[Fri Jul 20 15:51:14 2007] [notice] Server built: Jan 24 2007 23:31:11
[Fri Jul 20 15:51:14 2007] [notice] Parent: Created child process 4500
[Fri Jul 20 15:50:57 2007] [notice] Child 4500: Child process is running
[Fri Jul 20 15:50:57 2007] [notice] async engine initialized successfully,
8 worker threads started
[Fri Jul 20 15:50:57 2007] [notice] Child 4500: Acquired the start mutex.
[Fri Jul 20 15:50:57 2007] [notice] Child 4500: Starting 150 worker
threads.
[Fri Jul 20 15:53:46 2007] [error] (70014)End of file found: An error
occurred when processing incoming CGP downstream data
[Fri Jul 20 15:53:46 2007] [error] (70014)End of file found: S 0x7AAA08:
ap_get_brigade failed
[Fri Jul 20 15:58:38 2007] [error] (70014)End of file found: An error
occurred when processing incoming CGP downstream data
[Fri Jul 20 15:58:38 2007] [error] (70014)End of file found: S 0x7A9FE8:

A CDF trace shows that there is an incoming connection when the error occurs. Following is a sample CDF trace:

mod_socks 09/21/2007 02:54:11.132 socks_create_conn: START, connection ID=149 allocating conn_rec
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: c->pool=00673068
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: local_ip=172.18.4.58
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: remote_ip=172.18.4.153
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: setting bucket_alloc=00675070
mod_socks 09/21/2007 02:54:11.132 socks_create_conn: FINISH
mod_socks 09/21/2007 02:54:11.132 socks_client_pre_connection START
mod_socks 09/21/2007 02:54:11.132 socks_client_pre_connection no destination – return OK
mod_multiplexer 09/21/2007 02:54:11.132 process_multiplexer_connection: START
mod_multiplexer 09/21/2007 02:54:11.132 process_multiplexer_connection: no need to enable multiplexing on this connection, FINISH

mod_cgp 09/21/2007 02:59:11.218 process_cgp_connection start
mod_cgp 09/21/2007 02:59:11.218 LockSessionEntry : Lock session 0x0 (lock: 0x6645C8).
mod_cgp 09/21/2007 02:59:11.218 request: create_request conn=0x66B158 conn->pool=0x66B048
mod_cgp 09/21/2007 02:59:11.218 request: create_request START created request pool from conn pool, r->pool=0x30D1048
mod_cgp 09/21/2007 02:59:11.218 request: calling ap_run_create_request to let other hooks run
mod_cgp 09/21/2007 02:59:11.218 request: create_request FINISH, returning request_rec
mod_cgp 09/21/2007 02:59:11.218 request: destroy_request destroy request pool r->pool=0x30D1048
mod_cgp 09/21/2007 02:59:11.218 UnlockSessionEntry : Unlock session 0x7A9FF0 (lock: 0x6645C8).
mod_cgp 09/21/2007 02:59:11.218 LockSessionEntry : Lock session 0x7A9FF0 (lock: 0x6645C8).
mod_cgp 09/21/2007 02:59:11.218 ProcessSocketRead enter: session=0x7a9ff0 Downstream
mod_cgp 09/21/2007 02:59:11.218 ProcessSocketRead:got an empty brigade
mod_cgp 09/21/2007 02:59:11.218 ProcessSocketRead exit
mod_cgp 09/21/2007 02:59:11.218 UnlockSessionEntry : Unlock session 0x7A9FF0 (lock: 0x6645C8).
mod_cgp 09/21/2007 02:59:11.218 LockSessionEntry : Lock session 0x7A9FF0 (lock: 0x6645C8).
mod_cgp 09/21/2007 02:59:11.218 ProcessSocketRead enter: session=0x7a9ff0 Downstream
mod_cgp 09/21/2007 02:59:11.220 ProcessSocketRead:ap_get_brigade failed
mod_cgp 09/21/2007 02:59:11.220 ProcessSocketRead exit
mod_cgp 09/21/2007 02:59:11.220 cgp_close_socket enter sock=0x66B090
mod_cgp 09/21/2007 02:59:11.220 cgp_close_socket exit
mod_cgp 09/21/2007 02:59:11.220 cgp_destory_session enter
mod_cgp 09/21/2007 02:59:11.220 cgp_destroy_session:Destroying session 0x7A9FF0
mod_cgp 09/21/2007 02:59:11.220 Session 0x0: CGPSDK: CGPCore: CgpDestroySession called with invalid session handle.
mod_cgp 09/21/2007 02:59:11.220 cgp_destory_session exit
mod_cgp 09/21/2007 02:59:11.220 UnlockSessionEntry : Unlock session 0x0 (lock: 0x6645C8).

Solution

The event log messages appear in the event log because of extra monitoring that is enabled in Presentation Server 4.5. You can use the following procedure to disable the option to display error messages that are not required. You can set the option to display only emergency errors. To do so, complete the following procedure:

Edit the httpd.conf file from the C:\Program Files\Citrix\XTE\conf\ folder using WordPad.

Add the following lines to the file:

# Log Level
loglevel emerg

Following is an excerpt of the file after adding the required content:

#CGP Listen Port
Listen 2598
# Log Level
loglevel emerg

Save and close the file. Restart the XTE service for the change to take effect.

Note: Restarting the server overwrites the file and the changes are lost.

  • Change file attribute (for httpd.conf) properties to Read-only.
  • Restart the computer. Note that the changes are saved. All the services are started.

Note: The Event ID message is benign and as per the design of the software.

Problem Cause

Scanning port 2598 causes the XTE service to receive unexpected data. Therefore, the error message is written to the Event Log.

Run the following command from the command line interface to replicate this scenario: C:\>telnet 172.18.4.58 2598.

Additional Resources

This same error message might be displayed on the Secure Gateway Servers Event Viewer Secure Gateway Logs. Following is the error message displayed:

Event Type: Error
Event Source: Secure Gateway
Event Category: CGP
Event ID: 103
Date: 11/9/2007
Time: 2:41:11 PM
User: N/A
Computer: YourCSGServer
Description: Incoming Citrix Gateway Protocol downstream data could not be processed.

This message can be replicated by stopping the Citrix XTE Service on the server running Presentation Server.

Note: The LogLevel can be set from the least detail to the most detail. Following are the various LogLevel settings:

emerg – emergency
alert
crit – critical
error
warn- warning
notice
info
debug

The default LogLevel setting is warn.

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