Is this a wireshark bug when display information about AMQP? - wireshark

I am using spring-amqp and testing RabbitListener#AcknowledgeMode.
When i set RabbitListener#AcknowledgeMode#AUTO,I triggered the nack reponse by thorwing a exception in my RabbitListener.
When i set defaultRequeueRejected to true(it means message will requeue), package by wireshark:
It looks like the last two bits represent these two properties.
And When i set defaultRequeueRejected to false(it means message will not requeue), package by wireshark:
Requeue should be false.So is this a wireshark bug? Or do I understand something wrong?

It looks like a wireshark bug to me 0x03 Vs. 0x01.
I just looked at the code in the client lib and the multiple bit is the LSB and the requeued bit is the next bit.

Related

Sending IFS File to Outq Prints Line of "#" Symbols

I am attempting to send a file from IFS to an outq on our AS/400 system. Whenever I do, I get exactly what I send, as well as a line of "#" symbols of varying lengths appended to the end.
Here's the command I'm using:
qsh cmd('cat -c /path/test.txt | Rfile -wbQ -c "ovrprtf file(qprint)
outq(*LIBL/ABCD) devtype(*USERASCII) rplunprt(*no) splfname(test) hold(*no)"
qprint')
The contents of test.txt is just Hello World!
The output I get when I send the command is
Hello World!####################################################################
I have not found any posts online about a similar problem, and have tried changing values and looking for additional switches to get it to work. Nothing I'm doing seems to fix the issue.
Is there a command or switch that I am missing, or is something I have in there already causing this?
EDIT:
I found this documentation which is the first time I've seen this issue mentioned, but it's not very helpful:
“Messages for a Take Action command might consist of a long string of "at" symbols (#) in a pop-up message. (The Reflex automation Take Action command, which is configured in situations, does not have this problem.) A resolution for this problem is under construction. This problem might be resolved by the time of the product release. If you see this problem, contact IBM Software Support.”
The only differences are: 1) this is not a pop-up message, it's printed. 2) I don't believe we use Tivoli Monitoring, although I could be wrong.
Assuming we do use Tivoli Monitoring, what would the solution be? There's no additional documentation past that, and I am not a system administrator, so I can't really make the call to IBM Software Support myself. And assuming we DON'T use it, what else could cause this issue?
I get different results, yet similar. I created a test.txt with Windows Explorer, put in Hello, world!, saved it and tried the script. I got gibberish for the 'Hello, world!' and then the line of # symbols.
My system is 7.3 TR5, CCSID 37 (US English) and my IFS file is CCSID 1252 (Windows English). Results did not change if I used a stream file of CCSID 819 (US ASCII).
I didn't have any luck modifying Rfile switches.
I found that removing devtype(*userascii) produced printed output in plain English without the # symbols. Do you really need *USERASCII? I would think that would be more for a pre-formatted 'print-ready' file like Postscript or the like.
EDIT: some more things to try
I don't understand why *USERASCII is adding those # symbols; it looks like a translation issue.
I tried this and still got the extra ###... You might have to play with the TOCCSID() parameter. Although a failure, it did give me an idea: what if those # symbols are EBCDIC spaces being sent as-is to the *USERASCII print stream? All we'd need is a way to send only the number of bytes in the stream file, without any padding.
CRTPF FILE(QTEMP/PRTSTMF) RCDLEN(132)
CPY OBJ('/path/test.txt') TOOBJ('/qsys.lib/qtemp.lib/prtstmf.file/prtstmf.mbr') replace(*yes)
ovrprtf file(qprint) outq(*LIBL/prt3812) devtype(*USERASCII) rplunprt(*no) splfname(test) hold(*no)
cpyf prtstmf qprint
The data in QTEMP/PRTSTMF is in ASCII; DSPPFM shows that much. It also shows a bunch of spaces: after all, it is a fixed length file. My next step was to write an RPG program to read the stream file and print it, but Scott Klement already did that: http://www.scottklement.com/PrtStmf.zip
This works on my system:
ovrprtf file(qsysprt) outq(*LIBL/abcd) devtype(*USERASCII) rplunprt(*no) splfname(test) hold(*no)
prtstmf stmf('/path/test.txt') outq(abcd)

LabVIEW and Keithley 2635A - Unable to read data

I'm using LabVIEW and its VISA capabilities to control a Keithley 2635A source meter. Whenever I try to identify the device, it works just fine, both in reading and writing.
viWRITE(*IDN?) /* VISA subVI to send the command to the machine */
viREAD /* VISA subVI to read output */
However, as soon as I set the voltage (or current), it does so. Then I send the command to perform a measurement, but I'm not able to read that data, with the error
VISA: (Hex 0xBFFF0015) Timeout expired before operation completed.
After that, I can not read the *IDN? output either anymore.
The source meter is connected to the PC via a National Instrument GPIB-USB-HS adaptor.
EDIT: I forgot to add, this happens in the VISA Interactive Control program as well.
Ok, apparently the documentation is not very clear. What the smua.measure.X() (where X is the needed parameter) command does is, of course, writing the measurement outcome on a buffer. In order to read that buffer, however, the simple viREAD[] is not sufficient.
So basically the answer was to simply add a print command: this way I have
viWRITE[print(smua.measure.X())];
viREAD[]
And I don't have the error anymore. Not sure why such a command is needed, but that's that. Thank you all for your time answering me.
As #Tom Blodget mentions in the comments, the machine may not have any response to read after you set the voltage. The *IDN? string is both command and query. That is, you will write the command *IDN? and read the result. Some commands do not have any response to read. Here's a quick test to see if you should be reading from the instrument. The following code is in python; I made up the GPIB command to set voltage.
sm = SourceMonitor()
# Prints out IDN
sm.query('*IDN?')
# Prints out current voltage (change this to your actual command)
sm.query('SOUR:VOLT?')
# Set a new voltage
sm.write('SOUR:VOLT 1V')
# Read the new voltage
sm.query('SOUR:VOLT?')
Note that question-marked GPIB commands and the query are used when you expect to get a response from the instrument. The instrument won't give a response for the write command. Query is a combination of write(...) and read(...). If you're using LabView, you may have to write the write and read separately.
If you need verification that the machine received your instruction and acted on it, most instruments have the following common commands:
*OPC? query to see if the operation is complete
SYST:ERR? query to see if any error was generated
Add a question mark ? to the end of the GPIB command used to set the voltage

Unable to read from Agilent 53131A by GPIB in the simple way

Hi I am using LabView 2012, Delphi XE7 and GPIB (I think 488.2), Win7 SP1 and Agilent 53131A.
I used the given NI examples.
NI Labview example - Found in LabVIEW's help - GPIB.vi.
I tried writing and reading to query frequencies from 2 channels and they are successful.
They are are sent and read in succession.
*IDN?
:FUNC 'FREQ 1'
:READ:FREQ?
If they are successful, that meant GPIB for Agilent and NI MAX and driver are successfully installed and configured.
I am also able to use KeySight Connection Expert's to write and read, Again it is also successful.
However, When I used the given NI example in Delphi. Orginally it was saved as Delphi 3 or 4.
I used the Scope Simple example for universal counter. I used it mostly for writing and reading in the simple way. All it needs initialization, read/write and cleanup
I changed the following codes as shown below, in SimpleForm.pas
The detected device is at GPIB0::3::INSTR so, at line 32,
PRIMARY_ADDR_OF_COUNTER = 3;
String to write and read so, at line 132,
CommandBox.Text := '*IDN?';
then it was compiled with no error and run.
String to write was successfully
But upon reading, it was not successfully.
The string output is supposed to be ' HEWLETT-PACKARD,53131A,0,4806'.
The error at the end of the program is as follows below:-
Unable to read from device
ibsta = SC000 <ERR TMO>
iberr = 6 <EABO>
ibcntl = 0
From these readings, I figured out as :-
EABO means abort
I am not familiar with working of GPIB. Kindly advise.
You are correct that EABO is the identifier for an abort. In addition, we can see from ibsta = SC000 <ERR TMO> that the cause of the abort was a GPIB timeout error. I am not familiar with Keysight Connection Expert or your instrument, but since the error was from GPIB timeout, the most likely causes are:
The query was improperly formatted and the instrument thought it was just a write statement with no response needed. (That's probably why the write function had no error, but the read function timed out.)
The query was improperly formatted and the instrument returned an error.
Instrument needs to have 'Talker' capability enabled to send data. (Most instruments do this automatically with queries.)
For more information on generic GPIB commands, see this reference from the folks at National Instruments.

Erlang Bit Syntax pattern matching works in shell but not as passed argument

I am trying to make a simple UDP packet decoder.
packet_decoder(Packet)->
<<Opts:8,MobIdLength:8,MobId:64,MobIdType:8,MgeType:8,SeqNum:16,Rest/binary>> = Packet,
io:format("Options:~p~n",Opts),
io:format("MobIdLength:~p~n",MobIdLength),
io:format("MobId:~p~n",MobId),
io:format("MobIdType:~p~n",MobIdType),
io:format("MgeType:~p~n",MgeType),
io:format("SeqNum:~p~n",SeqNum).
Packet is passed by a receive loop:
rcv_loop(Socket) ->
inet:setopts(Socket, [{active, once}, binary]),
io:format("rcvr started:~n"),
receive
{udp, Socket, Host, Port, Bin} ->
packet_decoder(Bin),
rcv_loop(Socket)
end.
I keep getting(following error edited 9/7/12 9:30 EST):
** exception error: no match of right hand side value
<<131,8,53,134,150,4,149,0,80,15,1,2,1,2,0,16,80,71,115,
52,80,71,115,53,24,63,227,197,211,...>>
in function udp_server:packet_decoder/1
called as udp_server:packet_decoder(<<131,8,53,134,150,4,149,0,80,15,
1,2,1,2,0,16,80,71,115,52,80,71,
115,53,24,63,227,197,...>>)
in call from udp_server:rcv_loop/1
in call from udp_server:init/0
If I create the same variable in the Erlang shell as a binary, i.e.
Packet = <<131,8,53,134,150,4,149,0,80,15,1,2,1,2,0,16,80,71,115,52,80,71,115,53,24,63,227,197,211,228,89,72,0,0,0,0,0,0,0,16,0,5,5,32,1,4,255,159,15,18,28,0,34,62,2,0,0,0,0,0,0,0,47,67>>.
<<Opts:8,MobIdLength:8,MobId:64,MobIdType:8,MgeType:8,SeqNum:16,Rest/binary>> = Packet.
It works just fine. Is there some subtlety in passing this to a function that I am missing? I have tried what I think is everything(except the right way). I tried setting the type and size. I also just tried
<<Rest/binary>> = Packet.
To no avail. Any help much appreciated.
The error you are getting when you run your code does not match your code. The error you are getting:
** exception error: no match of right hand side value ...
is a badmatch error and comes from an explicit = match where the pattern does not match the value from the RHS. There is no = in the code for rcv_loop/1. This implies that the loop you are running is not this code. So there are some questions to be asked:
When you have recompiled the module containing rcv_loop/1 have you restarted the loop so you run the new code? This is not done automagically.
Are you sure you are loading/running the code you think you are? I know this question sounds stupid but it is very easy, and not uncommon, to work on one version of the code and load another. You need to get the paths right.
The other things about mentioned about your code would not give this error. The calls to io:format/2 are wrong but would result in errors when you make the actual calls to io:format/2. Using the variable Socket as you do is not an error, it just means that you only want to receive UDP packets from just that socket.
EDIT : the first part of my answer was completely wrong so in order to not mislead, I deleted it.
Like spotted Alexey Kachayev io:format takes as second parameter a list, so :
packet_decoder(Packet)->
<<Opts:8,MobIdLength:8,MobId:64,MobIdType:8,MgeType:8,SeqNum:16,Rest/binary>> = Packet,
io:format("Options:~p~n",[Opts]),
io:format("MobIdLength:~p~n",[MobIdLength]),
io:format("MobId:~p~n",[MobId]),
io:format("MobIdType:~p~n",[MobIdType]),
io:format("MgeType:~p~n",[MgeType]),
io:format("SeqNum:~p~n",[SeqNum]).
I figured it out(kinda). I had been working on this in erlide in eclipse which had worked fine for all of the other parts of the. I tried compiling it from the erl shell and it worked fine. There must be some minor difference in the way eclipse is representing the source or the way it invokes the erlang compiler and shell. I will take it up with erlide.org. Thanks for the help!

SOCKS 5 - Failure behaviour?

I have read the RFC1928 several times and still couldn't understand what a compliant SOCKS 5 server is supposed to reply in case of failure. This doubt comes from the fact that the ATYP, BND.ADDR and BND.PORT fields from a SOCKS reply simply don't make sense if, for instance, a request with an invalid command is received. Must the server not send these fields or just send blanks?
I just red putty source code, and found out that, when there is an error in reply (REP != 0) ATYP is IPv4 (1) BND.ADDR and BND.PORT are all NULL bytes.
I guess this behavior helps developpers to parse requests ?
In a failure reply, only the VER and REP fields are meaningful. The other fields may be present but are not used. You don't even need to look at those bytes unless REP is zero.

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