[Click] LLRPC Examples

[Cliff Frey]

please always include the click mailing list in your replies (but I messed
this up too, so sorry about that).

The documentation is confusing.  Because you *can* sent arguments to a read
handler (and a read handler can modify state).

I would grep for READ_PARAM in the elements/ directory.  I would look at
IPRouteTable's 'lookup' handler for an example.

Cliff


On Fri, May 14, 2010 at 10:25 AM, Sanhueza, Patricio <
patricio.sanhueza at gdcanada.com> wrote:

>  Hi Cliff
>
>
>
> Sorry, it stemmed from misreading/misinterpreting the following line on the
> click website
>
>
>
> There is currently no way to *pass data to a read handler *or *return data
> from a write handler*. Use LLRPCs if you need a more RPC-like read-write
> interface
>
>
>
> http://read.cs.ucla.edu/click/element
>
>
>
> I am kind of confused as how to pass data into a read handler? Or get data
> back from a write handler? How do the optional parameters work in
>
> *READ **handler** [**params…**]*
>
> Call a read *handler*, passing the *params*, if any, as arguments, and
> return the results. On success, responds with a "success" message (response
> code 2xy) followed by a line like "DATA *n*". Here, *n* is a decimal
> integer indicating the length of the read handler data. The *n* bytes
> immediately following (the CRLF that terminates) the DATA line are the
> handler's results.
>
>
>
> The callback signature for a read handler is
>
>
>
> String (*ReadHandler) (Element *element, void *thunk) //how to I get access
> to the parameters?
>
>
>
>
>
> Essentially I need an interface into an element that I can pass data into
> it, and it return data back, so that is why I was looking into the LLRPC
> mechanism instead.
>
>
>
> I looked at the ControlSocket documentation but I am looking for a concrete
> example.
>
>
>
> Example::  LLRPC counter#0xC004C001 4 ????
>
>
>
> Thanks,
>
>
>
> Patricio
>
>
>
> *From:* Cliff Frey [mailto:cliff at meraki.com]
> *Sent:* Friday, May 14, 2010 11:01 AM
> *To:* Sanhueza, Patricio
> *Subject:* Re: [Click] LLRPC Examples
>
>
>
> look at the documentation for ControlSocket
> http://read.cs.ucla.edu/click/elements/controlsocket
>
>
>
> Although I'm curious why you are interested in the LLRPC mechanism.  It is
> generally much easier to use read, write, or read+param handlers to
> implement this sort of functionality (these can also be accessed over
> controlsocket).
>
>
>
> Cliff
>
> On Fri, May 14, 2010 at 6:44 AM, Sanhueza, Patricio <
> patricio.sanhueza at gdcanada.com> wrote:
>
> Hello
>
> I am wondering if I can get an example of using LLRPC with say the
> Counter element? More specifically, what would be the server command
> message sent to the ControlSocket to get the count? I am trying to test
> this on the standard elements before implementing a custom one. Also, is
> there any documentation on LLRPC within click that I can get my hands
> on? There is paper on the Internet called "Programming the Click Modular
> Router", but the LLRPC section is empty.
>
> Patricio
>
>
>
>
>
>
>
>
>
>
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