Forum Discussion

Srikanth_79730's avatar
Srikanth_79730
Icon for Nimbostratus rankNimbostratus
Feb 06, 2012

iRules to verify binary data from TCP::payload

Hey Folks,

 

 

Good day. I am newbie to F5/irules. Need help from you guys to solve my first task on irule :)

 

 

I have a pool of 3 servers. The incoming traffic is a TCP binary stream. The idea is to collect the first two bytes of data after client side TCP connection setup and based on that determine which server to redirect to in the pool.

 

 

For example:

 

 

1. if the first two bytes are "00000000 000000001", then direct traffic to Server 1.

 

 

2. if the first two bytes are "00000000 000000010", then direct traffic to Server 2.

 

 

3. if the first two bytes are "00000000 000000011", then direct traffic to Server 3.

 

 

 

I have written a simple irule as below, but its not working. I tried comparing using regexp and operators such as "contains/equals/starts_with". But it doesnt seem to compare well. I know that this is a string formatting problem. (I read the documentation of TCP::payload, it talks about the default format is UTF8, but somehow could not figure a fix)

 

 

Can you please help me out here on how to compare the binary data received from TCP::payload.

 

 

 

 

-------------------------------------------------

 

 

when CLIENT_ACCEPTED

 

{

 

TCP::collect 2

 

}

 

 

when CLIENT_DATA

 

{

 

set msid [TCP::payload 2]

 

 

 

if { [regexp "\x00\x00" $msid] }

 

{

 

pool lb-pool member 10.224.115.141 30003

 

}

 

elseif { [regexp -indices "\x00\x01" $msid] }

 

{

 

pool lb-pool member 10.224.115.142 30003

 

}

 

elseif { [regexp -indices "\x00\x10" $msid] }

 

{

 

pool lb-pool member 10.224.115.143 30003

 

}

 

else

 

{

 

pool ss-blitz01-pool-30003 member 10.224.115.140 30003

 

}

 

 

TCP::release

 

}

 

 

-------------------------------------

 

 

 

- Thanks in advance

 

Srikanth

 

application delivery
dev
devops
iRules

1 Reply

Sort By
  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    Feb 06, 2012
    can you add log command something like this? 

    [root@ve1023:Active] config  b rule myrule list
rule myrule {
   when CLIENT_ACCEPTED {
   TCP::collect 2
}

when CLIENT_DATA {
   set msid [TCP::payload 2]
   binary scan $msid H* msid_hex
   log local0. "\$msid: $msid"
   log local0. "\$msid_hex: $msid_hex"
   TCP::release
}
}

[root@ve1023:Active] config  cat /var/log/ltm
Feb  5 23:56:26 local/tmm info tmm[4369]: Rule myrule CLIENT_DATA: $msid: GE
Feb  5 23:56:26 local/tmm info tmm[4369]: Rule myrule CLIENT_DATA: $msid_hex: 4745