[Click] About the IPClassifier

[Eddie Kohler]

Hi Roberto,

IPClassifier programs use C's rules for whether a number is in hex, decimal, 
or octal.  0034 is interpreted as 34 octal, or 28 (== 0x1c hex).  You want

ip[2:2] 0x0034

If you're ever interested in what IPClassifier is doing try something like this:

mug% click -e 'Idle -> IPClassifier(ip[2:2] 0034) -> Idle' -qh '*.program'
IPClassifier at 2.program:
  0   0/0000001c%0000ffff  yes->[0]  no->[1]
safe length 4
alignment offset 0

Eddie


Roberto Riggio wrote:
> Hi,
> 
> I'm using the IPClassifier element to match all the IP packets 
> with a total length equal to 52 bytes:
> 
> IPClassifier(ip[2:2] 0034, -)
> 
> However when I run my configuration no packet are emitted on 
> port 0. I'm double checking with wireshark if indeed there are 
> such packets.
> 
> What am I doing wrong?
> 
> Bye
> Roberto
>