Joe Orton wrote:
On Fri, Aug 19, 2005 at 12:07:37AM -0700, Stas Bekman wrote:
Joe Orton wrote:
On Thu, Aug 18, 2005 at 06:25:23PM -0700, Stas Bekman wrote:
when reading from most bucket types you want to read all the data. This
is not the case with socket buckets, since the amount of data on the
socket can be anything. At the moment the code hardcodes 8K of data is to
be read. What do I do if I want to control how much data is read from the
socket?
Why do you need to do that? You shouldn't really care.
We do care, because we write a throttling filter for the smtp module, so
we want to slow down the spammers, reading 8K defeats the purpose of the
throttling filter (we read like 32B and then sleep), since most spam
messages will be consumed by the server side. that filter will be
available on CPAN once completed.
Hmmm, tricky. I would suspect it would be better to achieve this using
socket options, though I'm not sure how feasible that is; e.g. try
setting SO_RCVBUF to 32. You really want to prevent the TCP stack from
buffering and ACKing the data as well if you want to throttle the sender
from the word go.
But that still won't prevent from the bucket socket read function to read
more than 32, if while it cleans the buffer the OS level keeps on reading
the data in, is that correct? or is it absolutely sure that the smaller
buffer size will make sure that the socket buffer will never read more
than that?
Also while we are at it, do you remember why 8000 was chosen as the size
of the buffer (I remember why it wasn't 8K, but I wonder why not 2k or
4k?) is it because it perfectly fits the memory page? but how do you
ensure that it always starts at the page boundary and not hanging over the
end of the previous page?
Otherwise, I guess what you could do here is implement a new bucket
type, which is a clone of SOCKET, except it stores a length parameter
which is used in the place of APR_BUCKET_BUFF_SIZE on each ->read()
invocation; allowing the caller to change the length as necessary using
an accessor function.
Right I could do that. But I'll also need to replace the core_in filter,
since it will use the current socket bucket functionality.
You can't change the apr_bucket_read() interface itself so I'm not sure
exactly what you were trying to do with the changes you mention.
I wasn't trying to, I was just hoping for a quick hack before a clean
solution is introduced. But never mind, I'll just work on the clean
solution when we will have time for that.
--
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