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st0n3_87491's avatar
st0n3_87491
Icon for Nimbostratus rankNimbostratus
Aug 13, 2009

Persistence based on IMAP-User

Hi there,

as topic say I would like to have a persistence to a node based on his IMAP-Userlogin.

I managed to find out this using a stream Profile and wrote this iRule so far: 

  
 when CLIENT_ACCEPTED {  
 STREAM::expression @LOGIN\.*@  
 STREAM::enable   
 event STREAM_MATCHED enable  
 }  
 when STREAM_MATCHED {  
 set match [getfield [STREAM::match] " " 2]  
 set client "[IP::client_addr]:[TCP::client_port]"  
 set vip [IP::local_addr]:[TCP::local_port]  
 set node "[IP::server_addr]:[TCP::server_port]"  
 log local0.info "$match $client $vip $node"  
 STREAM::disable  
 }

This iRule now just logs 

  
 Jul 15 19:08:54 tmm tmm[1867]: Rule persistence_irule_user : nocppp XX.XX.XXX.XXX:XXXXX(CLIENT-IP: PORT) XXX.XXX.XXX.XXX:XXX(VIP-IP: PORT) XXX.XXX.XXX.XXX:XXXX(NODE-ID: PORT)

As already mentioned in the next step I would like to have a persistance based on that LOGIN/Client-IP: PORT.

How can I manage this?

Next question is what happens to the persistent requests when the node goes down?

Maybe there are totally other solutions for that...because I have a performance issue on that solution, too.

Thanks in advance

Christian
application delivery
dev
devops
iRules

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  • hoolio's avatar
    hoolio
    Icon for Cirrostratus rankCirrostratus
    Aug 26, 2009
    Sorry, I'm confusing myself and you... the rule as it is is adding a persistence record based on the LOGIN in the request payload. The latest update I added tries to look that persistence record up using the client IP address. That won't exist as it wasn't added with the client IP as the persistence key.

    Can you try this? I'd test it myself but I'm short on time at the moment.

    Aaron 

     
 when CLIENT_ACCEPTED { 
  
     Time in seconds to maintain the persistence record in LTM's session table 
    set timeout 1800 
  
     Define STREAM expression and enable STREAM filter to check for the login 
    STREAM::expression {@LOGIN\.*@} 
    STREAM::enable 
 } 
 when STREAM_MATCHED { 
  
    log local0. "[IP::client_addr]:[TCP::client_port]: Matched: [STREAM::match]" 
  
     Save the matched value 
    set imap_login [getfield [STREAM::match] " " 2] 
  
     Check if $imap_login isn't empty 
    if { $imap_login != "" }{ 
  
        $imap_login isn't empty...so let's continue 
        log local0. "IMAP Login Information found...continuing" 
  
        The iRule parser doesn't allow the persist command in STREAM_MATCHED. 
        It works though, so hide the command from the parser 
       set persist_cmd "persist uie $imap_login $timeout" 
       log local0. "[IP::client_addr]:[TCP::client_port]: Parsed: $imap_login \$persist_cmd: $persist_cmd" 
  
       eval $persist_cmd 
       persist uie $imap_login 
  
       log local0. "[IP::client_addr]:[TCP::client_port]: Added persistence record for $imap_login on server [IP::server_addr]:[TCP::server_port]. Exiting event for this response." 
       event STREAM_MATCHED disable 
  
    } else { 
        $imap_login is empty...let's stop this here 
       log local0. "no IMAP Login Information found...aborting" 
    } 
 } 
 when LB_SELECTED { 
  
    log local0. "[IP::client_addr]:[TCP::client_port]: Selected server [LB::server]" 
 } 
 when SERVER_CONNECTED { 
  
    log local0. "[IP::client_addr]:[TCP::client_port]: Connected server [IP::server_addr]" 
 }

  • Nat_Thirasuttakorn's avatar
    Nat_Thirasuttakorn
    Icon for Employee rankEmployee
    Aug 26, 2009
    I think IMAP client and server has to chat a little before client tell server the login name.

     

    using stream profile might be too late.

     

    I believe you may have to do something like this smtp irule example. (let LTM chat to IMAP client until it knows login name, then pick server and repeat same conversation)

     

     

    http://devcentral.f5.com/wiki/default.aspx/iRules/SMTPProxy.html

     

     

    sorry if I misunderstood any thing.

     

    Nat
  • hoolio's avatar
    hoolio
    Icon for Cirrostratus rankCirrostratus
    Aug 26, 2009
    Hi Nat,

     

     

    That makes sense. It's a good suggestion. Unfortunately I don't have an IMAP server handy or the time to test this... and I imagine faking the IMAP server response from an iRule is going to be fairly technical for someone new to iRules.

     

     

    I can try testing this sometime, but I don't see it happening in the next week or two.

     

     

    Aaron
  • Nat_Thirasuttakorn's avatar
    Nat_Thirasuttakorn
    Icon for Employee rankEmployee
    Aug 27, 2009
    you may try this...

    this irule uses a lot of shortcut. it assumes that client just makes tcp connection and send capability command. For simplicity, the capability command is tripped off and is not forwarded to server. 

        
 when CLIENT_ACCEPTED {  
     TCP::respond "* BIG-IMAP ready\r\n"  
     set state "capability"  
      assume client will send capability as next command  
     TCP::collect  
 }  
 when CLIENT_DATA {  
     switch $state {   
         "capability" {  
             TCP::respond "* CAPABILITY IMAP4 IMAP4rev1 IDLE LITERAL+ LOGIN-REFERRALS MAILBOX-REFERRALS NAMESPACE AUTH=NTLM\r\na0000 OK CAPABILITY completed.\r\n"  
             set state "login"  
              assume client will send login as next command  
             TCP::payload replace 0 [TCP::payload length] ""  
             TCP::collect  
         }  
         "login" {  
              find username and make load balancing decision here 
             log local0.alert "[TCP::payload]" 
             TCP::release  
         }  
     }  
 }

    you may have to change capability message (the specific line below) to match your server. Dont forget to put \r\n (or CRLF) as necessary.

    TCP::respond "* CAPABILITY .... "

    Nat