SNAT pool and persistence

Hi,

I know this post is very old , but i got into the same issue but the internet search for the irule has landed over here.

My goal is to match client IP to SNAT (one to one mapping). I found an irule, but that is very long (manual typing and for bigger subnet cannot apply since that will be longer than 65536 characters which irule can take).

when CLIENT_ACCEPTED {
if { [IP::addr [IP::client_addr] equals 172.16.56.10/32] }{
snat 172.16.56.10
}
if { [IP::addr [IP::client_addr] equals 172.16.56.11/32] }{
snat 172.16.56.11
}
if { [IP::addr [IP::client_addr] equals 172.16.56.12/32] }{
snat 172.16.56.12
}
.
.
.
.
"and till all the one to one mapping"
}

However, this is not useful for longer subnets.
Is there a way to match the third and last octect of the IP of the client to SNAT IP.
The above irule shows about the thrid octect only , is there a way to match 3rd and 4th octect?

Zanoob

  
  when CLIENT_ACCEPTED {  
    
      Use a local array to configure the 5 SNAT addresses  
     set snat_ips(0) 1.1.1.1  
     set snat_ips(1) 2.2.2.2  
     set snat_ips(2) 3.3.3.3  
     set snat_ips(3) 4.4.4.4  
     set snat_ips(4) 5.5.5.5  
    
      Use getfield to parse the third octet from the client IP address  
      Get the modulus of the third octet against the number of the SNAT IPs in the array  
     set snat_number [expr {[getfield [IP::client_addr] "." 3] % [array size snat_ips]}]  
     log local0. "Client IP: [IP::client_addr], SNAT number $snat_number, SNAT IP: $snat_ips($snat_number)"  
    
      Apply the SNAT  
     snat $snat_ips($snat_number)  
  }  
  

  
  when CLIENT_ACCEPTED {  
      Create some snat name to IP variables  
     set snat0_ip 1.1.1.1  
     set snat1_ip 2.2.2.2  
     set snat2_ip 3.3.3.3  
     set snat3_ip 4.4.4.4  
     set snat4_ip 5.5.5.5  
    
      Test with a dummy client IP address  
     set client_ip "10.11.12.13"  
     log local0. "\$client_ip: $client_ip"  
    
      Scan the dummy IP address for each octet  
     scan $client_ip {%[0-9].%[0-9].%[0-9].%[0-9]} a b c d  
     log local0. "result: \[expr {$c % 5}\]: [expr {$c % 5}]"  
    
      Use modulus 5 on the third octet  
     log local0. "Snat command: snat [set "snat[expr {$c % 5}]_ip"]"  
    
      Apply the SNAT IP to this connection  
     snat [set "snat[expr {$c % 5}]_ip"]  
  }