[Click] File operations in Click

[Eddie Kohler]

There are lots of examples.  An event is delivered to c on write.  Probably 
the most analogous code is in elements/ip/iproutetable.cc.  Check out 
add_handlers() and ctrl_handler() (ctrl_handler() is the element-specific code).

Eddie


Jelena Mirkovic wrote:
> That may work. Is there a sample code where I could see how to use the  
> write handler? What I'm not clear about is if I do e.g. write c.count  
> value (or whatever the syntax is) multiple times do I loop in c to  
> read this or is there an event delivered to c on write?
> 
> Thanks
> -------------------------------------
> Jelena Mirkovic
> Computer Scientist
> USC Information Sciences Institute
> 4676 Admiralty Way, Suite 1001
> Marina del Rey, CA 90292
> 310-448-9170
> 
> 
> On Jul 16, 2008, at 9:17 PM, Cliff Frey wrote:
> 
>> You could add a write handler to your element, and write these  
>> delays in (either one at a time, or a bunch at once).
>>
>> On Wed, Jul 16, 2008 at 8:00 PM, Jelena Mirkovic <mirkovic at isi.edu>  
>> wrote:
>> Well, Script element is not quite what I want. I want to read a set of
>> IPs and delays like this:
>>        MailScanner has detected a possible fraud attempt from  
>> "1.1.1.1" claiming to be MailScanner warning: numerical links are  
>> often malicious: 1.1.1.1 200
>>        MailScanner has detected a possible fraud attempt from  
>> "2.2.2.2" claiming to be MailScanner warning: numerical links are  
>> often malicious: 2.2.2.2 300
>> then remember them in the kernel module. When a packet comes from
>> MailScanner has detected a possible fraud attempt from "1.1.1.1"  
>> claiming to be MailScanner warning: numerical links are often  
>> malicious: 1.1.1.1 I want to impose 200 ms delay, and for  
>> MailScanner has detected a possible fraud attempt from "2.2.2.2"  
>> claiming to be MailScanner warning: numerical links are often  
>> malicious: 2.2.2.2 source 300 ms
>> delay. So I'm afraid some file reading is necessary and I cannot use
>> variables from Script.  Or am I missing some other Script
>> functionality that may be useful?
>>
>> Thanks
>> -------------------------------------
>> Jelena Mirkovic
>> Computer Scientist
>> USC Information Sciences Institute
>> 4676 Admiralty Way, Suite 1001
>> Marina del Rey, CA 90292
>> 310-448-9170
>>
>>
>> On Jul 16, 2008, at 7:03 PM, Roman Chertov wrote:
>>
>>> Jelena Mirkovic wrote:
>>>> I've been trying to write a kernel module in Click that reads
>>>> address  info from a file, then manipulates (drops or forwards)
>>>> packets for  the specified addresses. I've had problems with using
>>>> fopen -  basically click-install informs me that fopen is unknown
>>>> symbol even  though I've included stdio.h in my file. I seem to
>>>> remember Linux  kernel has a problem manipulating files. Is there
>>>> an easy way to open
>>> It is disallowed to use system calls inside the kernel.  It is
>>> possible to still use them with some trickery but is best not to do
>>> so.
>>>
>>> Take a look at the Script element; it might be what you are looking
>>> for.
>>>
>>> Roman
>>>
>>>> and read a file from a Click kernel module?
>>>> Thanks
>>>> -------------------------------------
>>>> Jelena Mirkovic
>>>> Computer Scientist
>>>> USC Information Sciences Institute
>>>> 4676 Admiralty Way, Suite 1001
>>>> Marina del Rey, CA 90292
>>>> 310-448-9170
>>>> _______________________________________________
>>>> click mailing list
>>>> click at amsterdam.lcs.mit.edu
>>>> https://amsterdam.lcs.mit.edu/mailman/listinfo/click
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> 
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