Alan Conway wrote:
On 01/26/2010 05:37 PM, Sandy Pratt wrote:
We recently encountered a situation where our unit tests were sending
a known-bad string of nonsense as a message header. We were surprised
to find that this apparently caused our ~6 month old build of qpidd to
crash upon receiving the message.
I tested our most recent build of qpidd and found that while the
broker (correctly) did not crash, there is still some upper limit on
the length of message headers. In the test below, I tried to send a
test message with a header ~67kB in length, and received the following
error on the broker side:
2010-01-26 14:29:13 error cluster(10.72.40.166:23674 READY) aborting
connection 10.72.40.166:23674-4805: illegal-argument: Not enough data
for field table. (qpid/framing/FieldTable.cpp:204)
2010-01-26 14:29:13 error cluster(10.72.40.166:23674 READY) aborting
connection 10.72.40.166:23674-4805: framing-error: Framing version
unsupported (qpid/framing/AMQFrame.cpp:113)
Without looking at the code, I presume the upper limit to be 2^16 bytes.
I have a few questions:
1) Are max message and header lengths documented anywhere?
2) Does the client do anything to validate the message and header
length? We're using the Java JMS client FWIW.
It's obviously sort of absurd to be sending headers this long, but I
thought I'd bring it up anyway.
Headers have to fit in one frame so they are restricted to the
max-frame-size which is 64k by default. It can be negotiated smaller
when connecting but it can't be bigger than 64k - it's a 16 bit length.
Message body is only limited by available memory (and allocated journal
space on disk if you're persisting them) The body is sent as a sequence
of frames with an "end of message" mark on the last one.
This isn't a protocol limitation. I believe the JMS client will send
multiple header frames if the headers are large. I would guess from this
that the broker isn't defragmenting multiple header frames properly.
--Rafael
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