Hi Anil, You need to use "trace-cmd record" command and run you client. For example. I chose to write a tcp simple client server application. Server running on remote machine listening on some port I executed below command to connect to the server using trace-cmd record Below command records all the event and function trace in the kernel, You can filter these function by passing "-e net:*" this command will generate a report of all the function that kernel executed. You can read the report afterwords. using trace-cmd report. #sudo trace-cmd record -e all ./tcpc 10.0.0.28 #ls #tcpc  tcpc.c  trace.dat #trace-cmd report You can also user perf command to trace the kernel functions. #sudo perf record -e probe:tcp_sendmsg #perf report perf examples can be found below. http://www.brendangregg.com/perf.html -Anand Moon On Tuesday, July 15, 2014 10:34 PM, Jeff Haran <Jeff.Haran@citrix.com> wrote: This helps me to see the forest for the trees. And it’s pretty current: http://upload.wikimedia.org/wikipedia/commons/3/37/Netfilter-packet-flow.svg Jeff Haran From:kernelnewbies-bounces@kernelnewbies.org [mailto:kernelnewbies-bounces@kernelnewbies.org] On Behalf Of Anil Joshi Sent: Tuesday, July 15, 2014 7:38 AM To: kernelnewbies Subject: Path of network packet in kernel Hi All, I am just new to all this,just wanted to trace the path of the packet since it enter the system(inside the kernel (functions and system calls)) and reaches the destination application. How to do that. Regards _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

Hi Anil, I had written TCP client (tcpc.c) and TCP server (tcps.c) programs for demo and testing purpose. Note : "./tcpc" is the application running under trace-cmd record command. If you want to record the kernel flow for application you can use # trace-cmd record -e all command. # trace-cmd report             /* to see the output. */ See the man page of trace-cmd record for example for more details. Please find below link for more details how to filter the output. http://elinux.org/images/3/35/Kernelshark-tut-elc-2011.pdf -Anand Moon On Tuesday, July 22, 2014 4:51 PM, Anil Joshi <aj27744@gmail.com> wrote: Hi Anand, I did what you said but i am getting a strange output  [root@machine0 Desktop]#ls cli              trace.dat.cpu11  trace.dat.cpu2  trace.dat.cpu7 client.c         trace.dat.cpu12  trace.dat.cpu3  trace.dat.cpu8 trace.dat.cpu0   trace.dat.cpu13  trace.dat.cpu4  trace.dat.cpu9 trace.dat.cpu1   trace.dat.cpu14  trace.dat.cpu5 trace.dat.cpu10  trace.dat.cpu15  trace.dat.cpu6 [root@hwcentos10 Desktop]# cat trace.dat.cpu cat: trace.dat.cpu: No such file or directory [root@machine0 Desktop]# cat trace.dat.cpu0 [root@machine0 Desktop]# tcpc client.c trace.dat.cpu1 -bash: tcpc: command not found why am i getting so much trace.dat.cpu files and tcpc command not found can you please help me out.... cli is the executable file for client ---Anil On Wed, Jul 16, 2014 at 12:27 AM, Anand Moon <moon.linux@yahoo.com> wrote: Hi Anil,

You need to use "trace-cmd record" command and run you client. For example.

I chose to write a tcp simple client server application. Server running on remote machine listening on some port I executed below command to connect to the server using trace-cmd record Below command records all the event and function trace in the kernel,

You can filter these function by passing "-e net:*" this command will generate a report of all the function that kernel executed. You can read the report afterwords. using trace-cmd report.

#sudo trace-cmd record -e all ./tcpc 10.0.0.28 #ls #tcpc  tcpc.c  trace.dat #trace-cmd report

You can also user perf command to trace the kernel functions.

#sudo perf record -e probe:tcp_sendmsg

#perf report

perf examples can be found below.

http://www.brendangregg.com/perf.html

-Anand Moon

On Tuesday, July 15, 2014 10:34 PM, Jeff Haran <Jeff.Haran@citrix.com> wrote:

This helps me to see the forest for the trees. And it’s pretty current:

http://upload.wikimedia.org/wikipedia/commons/3/37/Netfilter-packet-flow.svg

Jeff Haran

From:kernelnewbies-bounces@kernelnewbies.org [mailto:kernelnewbies-bounces@kernelnewbies.org] On Behalf Of Anil Joshi Sent: Tuesday, July 15, 2014 7:38 AM To: kernelnewbies Subject: Path of network packet in kernel

Hi All,

I am just new to all this,just wanted to trace the path of the packet since it enter the system(inside the kernel (functions and system calls)) and reaches the destination application.

How to do that.

Regards

_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies