iRule to Log TLS Version and HTTP Host and URI

Yugandhar · ‎07-Aug-2020

Hi,

Created the following iRule to log the TLS ver info and HTTP Host and URI Details.

==========================================

when CLIENTSSL_HANDSHAKE {

if { [SSL::cipher version] == 1.0 || [SSL::cipher version] == 1.1 || [SSL::cipher version] == 1.2 }{

set FLAG 1

set TLS-VER [SSL::cipher version]

}

when HTTP_REQUEST {

if { $FLAG } {

set VIP [IP::local_addr]:[TCP::local_port]

set CLIENT [IP::client_addr]:[TCP::client_port]

set URL [HTTP::host][HTTP::uri]

log local0. "Client ($CLIENT) connected to the VIP ($VIP) for $URL using $TLS-VER"

}

=================================================

When the iRule is executed it throws the following error message in /var/log/ltm

- can't read "FLAG": no such variable while executing "if { $FLAG } { set VIP [IP::local_addr]:[TCP::local_port] set CLIENT [IP::client_addr]:[TCP::client_port] set URL [HTTP::host]..."

=============================================================

FLAG variable is created in SSL Client Handshake Event and that's passed over to HTTP Request event but i m not sure why it says no variable called FLAG.

Could you please help me in executing this iRule correctly

Thanks,

Yugandhar.

Enes_Afsin_Al · ‎07-Aug-2020

Hi Yugandhar,

[SSL::cipher version] : Returns the current SSL cipher version using the format of the OpenSSL SSL_CIPHER_get_version() function (e.g. “SSLv2”, “SSLv3”, “TLSv1”, “TLSv1.1”, “TLSv1.2”).

REF: https://clouddocs.f5.com/api/irules/SSL__cipher.html

when CLIENTSSL_HANDSHAKE {
	if { [SSL::cipher version] equals "TLSv1" || [SSL::cipher version] equals "TLSv1.1" || [SSL::cipher version] equals "TLSv1.2" }{
		set FLAG 1
		set TLS-VER [SSL::cipher version]
	}
	else {
		set FLAG 0
	}
}
 
when HTTP_REQUEST {
	if { $FLAG } {
		set VIP [IP::local_addr]:[TCP::local_port]
		set CLIENT [IP::client_addr]:[TCP::client_port]
		set URL [HTTP::host][HTTP::uri]
		log local0. "Client ($CLIENT) connected to the VIP ($VIP) for $URL using $TLS-VER"
	}
}

You don't need CLIENTSSL_HANDSHAKE event in iRule:

when HTTP_REQUEST {
	set TLS-VER [SSL::cipher version]
	set VIP [IP::local_addr]:[TCP::local_port]
	set CLIENT [IP::client_addr]:[TCP::client_port]
	set URL [HTTP::host][HTTP::uri]
	log local0. "Client ($CLIENT) connected to the VIP ($VIP) for $URL using $TLS-VER"
}

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iRule to Log TLS Version and HTTP Host and URI