iRule to persist on tcp_content

Hi again,

Can you inspect a server response on TCP level, retrieve a value, modify it and send back to client? I need to get the value of a Max-Connections header from a server in an options response. Modify this value to insert the total Max-Connections value for all the servers in the pool and send it on its way back to the client.

I got the impression from forum that the Wizards like to see a little effort or a hack at a rule from the subscriber so here goes: (its not pretty!)

   
  Rule entry point  
 when SERVER_CONNECTED {  
     TCP::collect  
 }  
 when SERVER_DATA {  
      Collect 30 bytes to see if its an OPTIONS response  
     TCP::collect 30  
     set identifier [findstr [TCP::payload] "OPTIONS" 7 "\r"]  
     if {$identifier ne " "} {  
          if its an OPTIONS response, process the TCP..  
         TCP::collect 250  
          250 bytes should give me the Max-Connections header  
     } else { [[TCP::payload] contains "Max-Connections:"]} {  
         set MaxConn [[TCP::payload] value "Max-Connections:"]  
         TCP::respond $MaxConn  
         log local0. "OptionResponse: $MaxConn"  
     }  
      Flush collect data and release event hook point  
     TCP::release  
 } 
 

The "Max-Connections: 2000\r\n" header is very simple and tells me how mant TCP connections I can set up on my server.

I am a little bit weary of TCP::respond, for the moment I have not managed to retrieve the value of Max-Connections.

Finally I need to be able to modify this value for example by a factor of 10 and return this value to the client.

Thanks,

Vin.