For more information regarding the security incident at F5, the actions we are taking to address it, and our ongoing efforts to protect our customers, click here.

Forum Discussion

Magnum_IP's avatar
Magnum_IP
Icon for Nimbostratus rankNimbostratus
Feb 08, 2013

Splitting TCP payload and load balancing

I am receiving data over a single TCP connection which at present gets sent to one the the pool members in the pool attached to the VIP. The data received is actually a stream of identifiable chunks of data. My intention is to collect the data, split it and to send it on the the pool as separate TCP packets and have these packets round robinned to the two members of the pool.

 

I can collect the data from the TCP connection in CLIENT_ACCEPTED and can begin to process the payload in CLIENT_DATA but I am not sure how or in which event to invoke the pool member selection.

 

Can anybody throw me a pointer?

 

fergu5

 

config
design

1 Reply

  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    Feb 11, 2013
    i did a bit test using \n as message boundary. client is netcat and server is echo streamserver. firstly i used 10.2.4 hf4 but having an issue about multiple messages per packet (e.g. 1\n2\n3\n). anyway, one message per packet (e.g. 1\n) seems okay.

    i suspected it might be bug 383853. there is engineering hotfix available on 11.1.0 hf4, so i applied it and it seems a bit better. tcp::notify eom is command from the engineering hotfix. it is used to release parsed message. tcp::notify request/response is used in the past.

    Bug 383853 - Need a synchronous event to signal end of message from TCP rule event

    not sure if this is what you are looking for. anyway, this is my testing. hope it helps. 

    root@ve11enghf(Active)(/Common)(tmos) show sys version| grep -i -A 3 product
  Product  BIG-IP
  Version  11.1.0
  Build    2185.38
  Edition  Engineering Hotfix HF4

root@ve11enghf(Active)(/Common)(tmos) list ltm virtual bar
ltm virtual bar {
    destination 172.28.19.252:7
    ip-protocol tcp
    mask 255.255.255.255
    pool foo
    profiles {
        mblb { }
        tcp { }
    }
    rules {
        myrule
    }
    snat automap
    vlans-disabled
}
root@ve11enghf(Active)(/Common)(tmos) list ltm pool foo
ltm pool foo {
    members {
        200.200.200.101:7 {
            address 200.200.200.101
        }
        200.200.200.111:7 {
            address 200.200.200.111
        }
    }
}
root@ve11enghf(Active)(/Common)(tmos) list ltm rule myrule
ltm rule myrule {
    when CLIENT_ACCEPTED {
  log local0. "--"
  log local0. "[IP::client_addr]:[TCP::client_port] > [IP::local_addr]:[TCP::local_port]"
  TCP::collect
}
when CLIENT_DATA {
  set idx 1
  log local0. "--"
  log local0. "received [TCP::payload]"
  while {$idx <= [TCP::payload length]} {
    if {[TCP::payload $idx] ends_with "\n"} {
      log local0. "sent [TCP::payload $idx]"
      TCP::release $idx
      TCP::notify request
      TCP::notify eom
      set idx 1
    } else {
      incr idx
    }
  }
  TCP::collect
}
when SERVER_CONNECTED {
  log local0. "--"
  TCP::collect
}
when SERVER_DATA {
  set recvidx 1
  log local0. "--"
  log local0. "[IP::remote_addr]:[TCP::remote_port] > [IP::local_addr]:[TCP::local_port]"
  log local0. "received [TCP::payload]"
  while {$recvidx <= [TCP::payload length]} {
    if {[TCP::payload $recvidx] ends_with "\n"} {
      log local0. "sent [TCP::payload $recvidx]"
      TCP::release $recvidx
      TCP::notify response
      TCP::notify eom
      set recvidx 1
    } else {
      incr recvidx
    }
  }
  TCP::collect
}
}

 A. single message per packet

 clieint

[root@centos251 ~] nc 172.28.19.252 7
1 <--- (type in)
1 <--- (echo response)
2
2
3
3

 log

[root@ve11enghf:Active] config  tail -f /var/log/ltm
Feb 11 09:41:17 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:41:17 tmm info tmm[8822]: Rule /Common/myrule : 172.28.19.251:49509 > 172.28.19.252:7
Feb 11 09:41:19 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:41:19 tmm info tmm[8822]: Rule /Common/myrule : received 1
Feb 11 09:41:19 tmm info tmm[8822]: Rule /Common/myrule : sent 1
Feb 11 09:41:19 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:41:19 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:41:19 tmm info tmm[8822]: Rule /Common/myrule : 200.200.200.111:7 > 200.200.200.10:49509
Feb 11 09:41:19 tmm info tmm[8822]: Rule /Common/myrule : received 1
Feb 11 09:41:19 tmm info tmm[8822]: Rule /Common/myrule : sent 1
Feb 11 09:41:20 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:41:20 tmm info tmm[8822]: Rule /Common/myrule : received 2
Feb 11 09:41:20 tmm info tmm[8822]: Rule /Common/myrule : sent 2
Feb 11 09:41:20 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:41:20 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:41:20 tmm info tmm[8822]: Rule /Common/myrule : 200.200.200.101:7 > 200.200.200.10:49509
Feb 11 09:41:20 tmm info tmm[8822]: Rule /Common/myrule : received 2
Feb 11 09:41:20 tmm info tmm[8822]: Rule /Common/myrule : sent 2
Feb 11 09:41:21 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:41:21 tmm info tmm[8822]: Rule /Common/myrule : received 3
Feb 11 09:41:21 tmm info tmm[8822]: Rule /Common/myrule : sent 3
Feb 11 09:41:21 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:41:21 tmm info tmm[8822]: Rule /Common/myrule : 200.200.200.111:7 > 200.200.200.10:49509
Feb 11 09:41:21 tmm info tmm[8822]: Rule /Common/myrule : received 3
Feb 11 09:41:21 tmm info tmm[8822]: Rule /Common/myrule : sent 3


 B. multiple messages per packet

 client

[root@centos251 ~] cat data.txt
1
2
3
4
5
6
7
8
9
10

[root@centos251 ~] nc 172.28.19.252 7 < data.txt
2
4
6
8
10
1
3
5
7
9

 log

[root@ve11enghf:Active] config  tail -f /var/log/ltm
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : 172.28.19.251:49513 > 172.28.19.252:7
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : received 1 2 3 4 5 6 7 8 9 10
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 1
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 2
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 3
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 4
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 5
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 6
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 7
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 8
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 9
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 10
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : 200.200.200.111:7 > 200.200.200.10:49513
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : received 2 4 6 8 10
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 2
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 4
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 6
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 8
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 10
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : --
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : 200.200.200.101:7 > 200.200.200.10:49513
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : received 1 3 5 7 9
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 1
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 3
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 5
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 7
Feb 11 09:44:01 tmm info tmm[8822]: Rule /Common/myrule : sent 9