Forum Discussion
suyeup_77835
Nimbostratus
Nimbostratusneed count a HTTPheader Referer
hi.. my name is sooyeup.kim i'm from korea.
i need help.
now, my company have F5 L7-Switch.(four!!) but we don't have iRule engineer.
(customize the iRule is very hard!!T0T) i need this iRule.
1. Count a All Referer(HTTP::header) and IP
2. if some Referer is over the limit, drop that IP
i was write the this iRule, but that is wrong!!!T-T
when RULE_INIT {
array unset ::user array
set ::user { } array
set ::blocklist { } array
set ::refererlist{ }
set ::attacktime 10
set ::maxreferer 100
set ::holdtime 3 set ::referer }
when HTTP_REQUEST {
set ::referer [HTTP::header Referer]
if { ($::referer contains "mrtg") } {
if { [ info exists ::blocklist([IP::remote_addr]) ] } {
if {$::holdtime > [ expr [clock seconds] - $::blocklist([IP::remote_addr]) ] } {
drop log local5. "[IP::remote_addr] is HOLD" return
} else {
unset ::blocklist([IP::remote_addr]) log local5. "[IP::remote_addr] is released" }
}
if{[info exists ::refererlist]}{
if{[HTTP::header Referer] equals $::refererlist}{
if { [info exists ::user([IP::remote_addr],count)] } {
if { $::attacktime > [expr [clock seconds] - $::user([IP::remote_addr],duration)]} {
if {$::user([IP::remote_addr],count) > $::maxreferer } {
set ::blocklist([IP::remote_addr]) [clock seconds]
log local5. "[IP::remote_addr] is blocked"
drop
return
} else {
incr ::user([IP::remote_addr],count) 1
return
}
} else {
unset ::user([IP::remote_addr],count)
unset ::user([IP::remote_addr],duration) }
} else {
if { 20000 < [array size ::user] } {
array unset ::user array set ::user { } }
set ::user([IP::remote_addr],count) 1
set ::user([IP::remote_addr],duration) [clock seconds]
set ::refererlist([HTTP::header Referer]) }
}
}
}
}
help me please!
thank you..
5 Replies
hoolioCirrostratus
Are you on 10.x or 9.x? For 10.x, you'd want to use a subtable to store the Referers instead of a global array. You can use the table command to access and modify a subtable:
http://devcentral.f5.com/wiki/default.aspx/iRules/table
You'd also want to change ::referer to a local variable as a global variable will be changed by all TCP connections--not just the current connection.
Aaron- Here is an example i-rule which uses the tables. This irule counts connections on a per source IP basis. You can change it to count referrers instead.
rule connection_counter {
Irule, written by John Alam, Feb 21st, 2011.
This irule counts the connections from a source IP within a time interval. When the number connections
allowed within specified interval is exceeded, a message is logged and the measurement is restarted.
when RULE_INIT {
maxRate is the maximum number of connection an IP address can initiate in windowSecs interval.
set static::maxRate 10
WindowSec is the length of an interval in seconds.
set static::windowSecs 10
}
when CLIENT_ACCEPTED {
set srcip [IP::remote_addr]
set currtime [clock second]
set count [ table lookup -subtable conns $srcip]
if { $count > 0 } {
set count [incr -subtable Conns $srcip]
If frequency is more than ::maxRate send message to log.
Any existing record cannot have been more than windowSecs old.
Count is the number of connections within windowSecs.
if { $count > $static::maxRate } {
set elapsed_secs [expr $static::windowSecs - [table timeout -subtable conns -remaining $srcip]]
log "IP address <$srcip> Connected $count times within $elapsed_secs seconds"
we must delete and start over otherwise every subsequent new connecton will trigger a log message.
table delete -subtable conns $srcip
return
}
} else {
In this clause, either the user is new
or more than ::maxRate connections were established per windowSec and we issued a log message.
Or the lifetime (windowSec) has expired.
We are creating a new record.
table set -subtables conns $srcip 1 $static::windowSecs $static::windowSecs
log "New or refreshed user <$srcip> <$currtime> Connections $count interval remaining [table timeout -subtable conns -remaining $srcip]"
}
}
} 
suyeup_77835thank!!
but i need count same Referer T0T
if max referer is 3,
IP 1.1.1.1 Referer is A, B, C, A, A is drop.
because A is three~~
can i make it?- suyeup_77835thank!!
but i need count same Referer T0T
if max referer is 3,
IP 1.1.1.1 Referer is A, B, C, A, A is drop.
because A is three~~
can i make it? - Sure, you could take the code above and change it around to count the number of requests from a given referrer ([HTTP::header "referrer"]) and it should work fine. If you have any specific questions on how to make this work let us know.
Colin
