A Catch from the Codeshare: Network Translations
On the side of the road in northern Missouri just north of Mark Twain’s stomping grounds, there is a slice of hillside removed just to the side of the highway. In Arkansas, there’s a nondescript fiel...
Published Nov 21, 2016
Version 1.0
JRahm
Admin
Admin
Kai_Wilke
MVP
MVPHi Jason,
I was little bit surprised of the complexity of the provided iRule and ended up with a less complicated 20LinesOrLess edition...
when RULE_INIT {
set static::dg_net_tsl "dg_network_translations"
}
when CLIENT_ACCEPTED {
Read Data Group
set original_ip [getfield [IP::client_addr] "%" 1]
set dg_elements [class match -element $original_ip equals $static::dg_net_tsl]
if { $dg_elements ne "" } then {
set new_ip_prefix [findstr $dg_elements " " 1]
set cidr_mask [findstr $dg_elements "/" 1 " "]
IP to binary conversion
binary scan [binary format c4 [split $original_ip "."]] B* original_ip_bin
binary scan [binary format c4 [split $new_ip_prefix "."]] B$cidr_mask new_ip_prefix_bin
IP prefix translation and binary to IP conversion
binary scan [binary format B* "$new_ip_prefix_bin[string range $original_ip_bin $cidr_mask end]"] cccc oct1 oct2 oct3 oct4
set new_ip "[expr { $oct1 & 0xff } ].[expr { $oct2 & 0xff } ].[expr { $oct3 & 0xff } ].[expr { $oct4 & 0xff } ]"
SNAT
snat $new_ip
}
}
The iRule now translates the client IP by utilizing a rather simple
[string range]Cheers, Kai