Advanced iRules: Scan

@Jason,

Great job!!! This Tip help me a lot and I could to solve a ploblem that I had with SIP Header.

The SIP "Contact" Header have some "routerids", may be between six and eith into his. How I needed to use SNAT, the BIG-IP change the original IP into the "routers" and this caused a trouble to SIP comminication between client and SBC proxy, because the when the SBC received the packet, he sent back to the BIG-IP and not to the client.

Using your example I could save the routerid and the client IP into variables and replace that and the "routerid" into the SIP Response.

Follow my iRule:

when SIP_REQUEST {

set addr [IP::client_addr]

}

when SIP_RESPONSE {

 Check for 302 responses 
if {[SIP::response code] == 302} { 

    log local0. "302 OK"

    if {[scan [SIP::header value "Contact"] {%[^@]%[^,]%[^@]%[^,]%[^@]%[^,]%[^@]%[^,]%[^@]%[^,]%[^@]%s} a b c d e f g h i j k l] == 12} {

        log local0. "Parsed before change [SIP::header value "Contact"] into $a - $b - $c - $d - $e - $f - $g - $h - $i - $j - $k - $l"

        SIP::header remove "Contact" 

        SIP::header insert "Contact" "${a}@$addr>${c}@$addr>${e}@$addr>${g}@$addr>${i}@$addr>${k}@$addr>" 

        log local0. "Parsed after change [SIP::header value "Contact"] into $a - $b - $c - $d - $e - $f - $g - $h - $i - $j - $k - $l"
   }        
}

}

My question now is if rule can increase the load of CPU, because when I see the dump before Rule, the time to arraive the packet was 7ms and after the rule, 35ms.

Thanks a lot Luis Araujo