Hi all,

I've been using the Debian testing package of pound for quite a while now. 
Lately I've come across an issue that seems to have been brought up before with
no real answer.
http://www.apsis.ch/pound/pound_list/archive/2007/2007-03/1173859204000#1173859204000

We have been moving over websites from an old group of Windows server to Debian
and I decided after lots of research that pound is the very best http load
balancer.

The problem I came across recently is that one of our scripts takes an
extremely long URI (a small XML file) but it can't pass through pound.  After
digging around, I found 'MaxRequest' in the man page which states:

MaxRequest nnn
Request maximal size.  All requests will be limited to these many bytes.  If a
request contains more data than allowed an error 414 is returned. Default:
unlimited.

So I tried some different values, starting at 4096 and going up, then going
down.  That setting seems to be completely ignored.  Even though MaxRequest is
supposedly 'unlimited', after doing tests, I found that it is set to '1024',
and the config file is ignored.

I did some more digging on the internet and found a hint about editing a MAXBUF
constant and recompiling to enable longer URIs.  I downloaded the source and
started reading and reading.  I guess I am confused why there is even a MAXBUF
constant to begin with.  Shouldn't the buffer be dynamic? or limited to what
the config file (MaxRequest) says?  I also think that I found the part where
MaxRequest /should/ be checked, but isn't (in the get_headers function), with
just the comment:

        /* check for request length limit */
        logmsg(LOG_WARNING, "(%lx) e414 headers: request URI too long",
pthread_self());
        err_reply(cl, h414, lstn->err414);
        return NULL;

I really really like pound, but this one problem really kills the viability for
our XML script.  Are there reasons why the buffers aren't dynamic?  Is
'MaxRequest' a recent wishlist feature that is just in planning?

-Miles Raymond
ITI Internet Services

Miles,

The length of the request URL is limited by the MAXBUF parameter in
bytes (default: 1024, can be set to something else at compile time by using
--with-maxbuf=1024). Any URL request longer than MAXBUF will be rejected by
Pound, and never seen on the back-end web server.

The MaxRequest parameter in the config file defines how large the BODY
of a request is (for example, if you upload a file). Requests are allowed
through to the back-end, but the body (contents) are truncated to this
size.

Try rebuilding the source with the argument --with-maxbuf= with 8KB or
however large your URI is going to be. Make sure to do a make clean
_before_ rebuilding.

make clean
./configure --with-maxbuf=8192 --with-ssl=/usr/local/ssl/
make
make install


Hope this helps.

  Pound secure reverse proxy "how to"
  http://calomel.org/pound.html

--
  Calomel (at) http://calomel.org
  Open Source Research and Reference


On Tue, Apr 15, 2008 at 04:35:23PM -0700, Miles Raymond wrote:[...]

Calomel,

Thanks!  With your specific instructions, I was able to get a custom pound
working.

How likely is it that MAXBUF will become a config file parameter instead of
compiled in?  It still seems excessive to have a static 10k buffer for each
connection when only 12% of the requests are longer than 1k...

Or perhaps to have a static 1k buffer initially and if exceeded, dumped into a
dynamic buffer for that connection.  Then the majority of connections would
have no performance impact of dynamic buffers.

-Miles

Calomel wrote:[...][...][...]