I am working with Message Manufacturing Specification (MMS) in wireshark. The tool is unable to dissect the ACSE layer. It doesn't show any error but it shows the ACSE data as a part of MMS i.e., after the presentation layer, MMS is displayed. Kindly assist if there is a way for wireshark to distinguish both the layers.
Thanks.
This question is from 2012, but in 2016 Wireshark 2.2.0 is able to dissect ACSE (Association Control Service Element) in MMS PDUs. To test it, you can download MMS sample capture data from the Wireshark website and open it in Wireshark. You will see dissected ACSE such as:
ISO 8650-1 OSI Association Control Service
aarq
Padding: 7
protocol-version: 80 (version1)
aSO-context-name: 1.0.9506.1.1 (iso.0.9506.1.1)
called-AP-title: ap-title-form2 (1)
called-AE-qualifier: aso-qualifier-form2 (1)
calling-AP-title: ap-title-form2 (1)
calling-AE-qualifier: aso-qualifier-form2 (1)
user-information: 1 item
Related
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.
I have a ROS node that allows you to "publish" a data structure to it, to which it responds by publishing an output. The timestamp of what I published and what it publishes is matched.
Is there a mechanism for a blocking function where I send/publish and output, and it waits until I receive an output?
I think you need the ROS_Services (client/server) pattern instead of the publisher/subscriber.
Here is a simple example to do that in Python:
Client code snippet:
import rospy
from test_service.srv import MySrvFile
rospy.wait_for_service('a_topic')
try:
send_hi = rospy.ServiceProxy('a_topic', MySrvFile)
print('Client: Hi, do you hear me?')
resp = send_hi('Hi, do you hear me?')
print("Server: {}".format(resp.response))
except rospy.ServiceException, e:
print("Service call failed: %s"%e)
Server code snippet:
import rospy
from test_service.srv import MySrvFile, MySrvFileResponse
def callback_function(req):
print(req)
return MySrvFileResponse('Hello client, your message received.')
rospy.init_node('server')
rospy.Service('a_topic', MySrvFile, callback_function)
rospy.spin()
MySrvFile.srv
string request
---
string response
Server out:
request: "Hi, do you hear me?"
Client out:
Client: Hi, do you hear me?
Server: Hello client, your message received.
Learn more in ros-wiki
Project repo on GitHub.
[UPDATE]
If you are looking for fast communication, TCP-ROS communication is not your purpose because it is slower than a broker-less communicator like ZeroMQ (it has low latency and high throughput):
ROS-Service pattern equivalent in ZeroMQ is REQ/REP (client/server)
ROS publisher/subscriber pattern equivalent in ZeroMQ is PUB/SUB
ROS publisher/subscriber with waitformessage equivalent in ZeroMQ is PUSH/PULL
ZeroMQ is available in both Python and C++
Also, to transfer huge amounts of data (e.g. pointcloud), there is a mechanism in ROS called nodelet which is supported only in C++. This communication is based on shared memory on a machine instead of TCP-ROS socket.
What exactly is a nodelet?
Since you want to stick with publish/ subscribers, assuming from your comment, that services are to slow I would have a look at waitForMessage (Documentation).
And for an example on how to use it you can have a look at this ros answers question.
All you need to do is to publish your data and immediately call waitForMessage on the output topic and manually pass the received message to your "callback".
I hope this is what you were looking for.
To get this request/reply behaviour ROS has a mechanism called ROS service.
You can specify the input and output of your service in a service file similar to a ROS message definition. You can then call the service of a node with your input and the call will receive an output when the service is finished.
Here is a tutorial how to use this mechanism in python. If you prefer C++ there is also one, you should find it.
I have a requirement to expand required tree in decoded parameters of pcap file and validate a message in it.
Example:
Open "Transmission Control Protocol" as shown in screenshot and and validate for the message "This is an ACK to the segment in frame: 278".
Need to develop an automation script in Java for validating messages in pcap files . Currently am using jnetpcap lib.
Appreciate your inputs!.
You can't, without protocol analysis by yourself. A pcap file doesn't include such massages.
The message "This is an ACK to the segment in frame: 278" was generated by wireshark after TCP session analysis by itself. Even the frame number 278 was assigned by wireshark. A pcap file only contains packets' data.
I am using emqtt message broker for mqtt.
I am not a erlang developer and has zero knowledge on that.
I have used this erlang based broker, because after searching many open source broker online and suggestions from people about the advantage of erlang based server.
Now i am kind of stuck with the out put of the emqttd_cli trace command.
Its not json type and if i use a perl parser to convert to json type i am getting delayed output.
I want to know, in which file i could change the trace log output format.
I looked on the trace code of the broker and found a file src/emqttd_protocol.erl. An exported function named trace/3 has the code that you need.
Second argument of this function, named Packet, has the information of receive & send data via broker. You can fetch required data from it and format according to how you want to print.
Edit : Sample modified code added
trace(recv, Packet, ProtoState) ->
PacketHeader = Packet#mqtt_packet.header,
HostInfo = esockd_net:format(ProtoState#proto_state.peername),
%% PacketInfo = {ClientId, Username, ClientIP, ClientPort, Payload, QoS, Retain}
PacketInfo = {ProtoState#proto_state.client_id, ProtoState#proto_state.username, lists:nth(1, HostInfo), lists:nth(3, HostInfo), Packet#mqtt_packet.payload, PacketHeader#mqtt_packet_header.qos, PacketHeader#mqtt_packet_header.retain},
?LOG(info, "Data Received ~s", [PacketInfo], ProtoState);
I am communicating with CUPS using IPP protocol. I have all drivers for my printers installed in CUPS (using .ppd file) and printers got latest firmware.
When I query a job which a printer printing right now it says that the job's state is 'complete' before the printer even finish printing. It seems that the CUPS marks the job as 'complete' when it finish 'uploading' the file.
I would not expect this behaviour and I basically need to know when exactly the printer printed last paper for a job.
The code looks as follow. The self.printer().ippPrinter() is an instance of node-ipp and it points to a printer. To read the the state of the job I am using attribute 'job-state'.
var msg = {
"operation-attributes-tag": {
'job-id': id
}
};
self.printer().ippPrinter().execute("Get-Job-Attributes", msg, function(err, res){
var attributes = res['job-attributes-tag'];
self.setAttributes = attributes;
callback.call(self, attributes);
});
Does anyone know why I am having this issue or .. how to make it working?
Thank you!
CUPS can only forward job-states received from the printer. A lot of printer drivers and protocols work like 'fire and forget'.
Usually IPP printers allow CUPS and other clients to monitor the current job-state until it's finished/printed. Some manufacturers don't implement IPP properly and classify submitted jobs as printed - even if the printer has a paper jam!
Conclusion:
If your printer does not fully support IPP you probably won't be able to check for 'printed successfully'.
RFC 8011 5.3.7.1
If the implementation is a gateway to a printing system that never provides detailed status about the Print Job, the implementation MAY set the IPP Job’s state to ’completed’, provided that it also sets the ’queued-in-device’ value in the Job’s "job-state-reasons" attribute
#Jakub, you may well be communicating with CUPS using IPP... But are you sure that CUPS is communicating with the print device via IPP?
You can check this by running
lpstat -h cupsservername -v
This should return the device URI assigned to each print queue, which CUPS uses to address the actual printing device:
If that URI does contain ipp://, ipps://, http:// or https:// CUPS indeed talks IPP to the print device and you should be able to get actually correct status messages.
But if you see socket:// then CUPS is configured to use the AppSocket method (sometimes also called 'HP Jet Direct' or 'IP Direct Printing') to forward jobs. This is a "fire and forget" protocol. Basically it is the same as if you did run netcat print-device 9100 < myprintfile to shovel the printable data to port 9100 of the printer. The CUPS socket backend handling this spooling to the printer will not get any other acknoledgement from the printer than what TCP/IP provides confirming that the last packet was transfered. Hence it has to close down its process and report to the CUPS daemon successful-ok, even if the printer is still busy spitting out lots paper and will maybe never complete the full job because it runs into a paper jam...
If you see lpd:// the situation is similar (but uses port 515).
You may have success with a full status reporting by switching the CUPS-to-printdevice path from AppSocket or LPD to IPP like so:
sudo lpadmin -p printername ipp://ipaddress-of-printer
or
sudo lpadmin -p printername http://ipaddress-of-printer:631