Sets X-XSS-PROTECTION header for given array of domains via F5 LTM iRule

Site-X-XSS-PROTECTION.irule

#X-XSS-Protection iRule
#By: Pierce Fortin ([email protected])
#Checks for domain being requested on HTTP_Request, Sets flag for response rewrite if match 
#If match, It then checks for X-XSS-Protection as existing, if it doesn't exist it adds one
#If match and header !exist, It adds it.
#v1.0 6/19/2018 Initial write


when RULE_INIT 
{
	set static::xssprotectionDebugOn 0
}
when CLIENT_ACCEPTED 
{
	set logPrefix "[IP::client_addr]:[TCP::client_port]:xssprotection:\[HTTPS\]:\t"
	if { $static::xssprotectionDebugOn } { log local0. "$logPrefix: Client accepted" }
}

when HTTP_REQUEST {
	if { $static::xssprotectionDebugOn } { log local0. "$logPrefix: ### Begin processing Incoming" }
	set isxssprotectionDomain 0
    array set xssprotectionDomains 
    {
        "domain.com"
        "domain2.com"
    }
    foreach domain [array get xssprotectionDomains]
    {
		if { $static::xssprotectionDebugOn } { log local0. "$logPrefix: Checking [HTTP::host] against $domain" }
        if { [string tolower [HTTP::host]] eq [string tolower $domain] } {
			if { $static::xssprotectionDebugOn } { log local0. "$logPrefix: Current request is an xssprotection domain. Processing" }
        	set isxssprotectionDomain 1
   		}
	}
}

when HTTP_RESPONSE {
	if { $static::xssprotectionDebugOn } { log local0. "$logPrefix: Processing Response" }
    if { $isxssprotectionDomain eq 1 } {
    	if { $static::xssprotectionDebugOn } { log local0. "$logPrefix: Current request is an xssprotection domain. Inserting xssprotection" }
        if { not([HTTP::header exists "X-XSS-Protection"])}{
            if { $static::xssprotectionDebugOn } { log local0. "$logPrefix: Could not find existing X-XSS-Protection header. Inserting" }
            HTTP::header insert "X-XSS-Protection" "1"
        }
        else {
            if { $static::xssprotectionDebugOn } { log local0. "$logPrefix: Found existing X-XSS-Protection header, Replacing" }
            HTTP::header replace "X-XSS-Protection" "1"
        }     
	}
}