# Re: Asking help about "gr-ieee802-11" **URL:** \ **Category:** GNU Radio\ **Created:** [January 29, 2015, 8:39am UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987 "2015-01-29T08:39:36Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\ **Post date:** [January 29, 2015, 8:39am UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987/1 "2015-01-29T08:39:36Z")
Dear Sir, I am referring to the same problem in [https://www.ruby-forum.com/topic/4487026](https://www.ruby-forum.com/topic/4487026) but I am using Debian 7.7 AMD64. I am facing exactly the same problem, as below: It said i should open “/examples/wifi\_phy\_hier.grc” in gnuradio-companion and build it but when i open it, one of the block (ID: header formatter) appear wrong. error messages: Param - Value(value): Value “ieee802\_11.wifi\_signal\_field()” cannot be evaluated: name ‘ieee802\_11’ is not defined Question: I am actually using the default prefix, which is /usr/local. How should I solve the problem then? Version info: sgku@mmu2: ~ $ echo $PYTHONPATH /usr/local/lib/python2.7/dist-packages sgku@mmu2: ~ $ uname -a Linux mmu2 3.2.0-4-686-pae #1 SMP Debian 3.2.63-2+deb7u1 i686 GNU/Linux sgku@mmu2: ~ $ cat /etc/debian\_version 7.7 sgku@mmu2: ~ $ gnuradio-config-info -v 3.7.5.1 Regards, Activecat ---
**Author:** ![activecat\_k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c57346/32.png) [@activecat\_k](https://www.ruby-forum.com/u/activecat_k)\ **Post date:** [January 29, 2015, 9:04am UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987/2 "2015-01-29T09:04:04Z")
Hi, > On 29 Jan 2015, at 08:37, Activecat [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > error messages: > Param - Value(value): > Value “ieee802\_11.wifi\_signal\_field()” cannot be evaluated: > name ‘ieee802\_11’ is not defined Please start an interactive python session and ‘import ieee802\_11’. This will give you more debug output. I guess either your $PYTHONPATH does not contain the path of the module or some shared library can not be loaded. Best, Bastian ---
**Author:** ![activecat\_k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c57346/32.png) [@activecat\_k](https://www.ruby-forum.com/u/activecat_k)\ **Post date:** [January 29, 2015, 9:17am UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987/3 "2015-01-29T09:17:49Z")
Dear Sir, Thank you very much for your prompt response. I really appreciate your help. Refer below result: sgku@mmu2: ~ $ ipython Python 2.7.3 (default, Mar 14 2014, 11:57:14) Type “copyright”, “credits” or “license” for more information. IPython 0.13.1 – An enhanced Interactive Python. ? → Introduction and overview of IPython’s features. %quickref → Quick reference. help → Python’s own help system. object? → Details about ‘object’, use ‘object??’ for extra details. ## In [1]: import ieee802\_11 ImportError Traceback (most recent call last) in () ----\> 1 import ieee802\_11 /usr/local/lib/python2.7/dist-packages/ieee802\_11/ **init**.py in () 35 36 # import swig generated symbols into the test namespace —\> 37 from ieee802\_11\_swig import \* 38 39 # import any pure python here /usr/local/lib/python2.7/dist-packages/ieee802\_11/ieee802\_11\_swig.py in () 24 fp.close() 25 return \_mod —\> 26 \_ieee802\_11\_swig = swig\_import\_helper() 27 del swig\_import\_helper 28 else: /usr/local/lib/python2.7/dist-packages/ieee802\_11/ieee802\_11\_swig.py in swig\_import\_helper() 20 if fp is not None: 21 try: —\> 22 \_mod = imp.load\_module(‘\_ieee802\_11\_swig’, fp, pathname, description) 23 finally: 24 fp.close() ImportError: dynamic module does not define init function (init\_ieee802\_11\_swig) On Thu, Jan 29, 2015 at 4:02 PM, Bastian B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![activecat\_k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c57346/32.png) [@activecat\_k](https://www.ruby-forum.com/u/activecat_k)\ **Post date:** [January 29, 2015, 9:37am UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987/4 "2015-01-29T09:37:34Z")
Either python3 is selected by cmake or (maybe) your swig version does not work. The first problem should have been fixed with the most recent commit (3 days ago). > sgku@mmu2: ~ $ ipython > In [1]: import ieee802\_11 > 39 # import any pure python here > 21 try: > > Best, > Bastian – Dipl.-Inform. Bastian B. Distributed Embedded Systems Group University of Paderborn, Germany > **[Home](https://www.bastibl.net/)** > > I'm Bastian Bloessl, a Research Group Leader at the Secure Mobile Networking Lab, TU Darmstadt. Checkout my blog, projects, publications, and resume; or connect on Github, Twitter, YouTube, or Facebook. ---
**Author:** ![activecat\_k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c57346/32.png) [@activecat\_k](https://www.ruby-forum.com/u/activecat_k)\ **Post date:** [April 23, 2015, 1:36pm UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987/5 "2015-04-23T13:36:17Z")
Dear Sir, Today I helped my friend to setup the gr-ieee802-11. Everything go well until I try to execute the flowgraph of wifi\_loopback.grc All ports in the GRC are connected. But when I run the wifi\_loopback.grc, it stops immediately with below message. ``` Generating: ``` “/home/sgku/download/zz-downloaded/gr-ieee802-11/examples/wifi\_loopback.py” \>\>\> Warning: This flow graph may not have flow control: no audio or RF hardware blocks found. Add a Misc-\>Throttle block to your flow graph to avoid CPU congestion. ``` Executing: ``` “/home/sgku/download/zz-downloaded/gr-ieee802-11/examples/wifi\_loopback.py” ``` linux; GNU C++ version 4.7.2; Boost_104900; ``` UHD\_003.008.001-121-gebe7169d ``` Using Volk machine: avx_32_mmx_orc OFDM MAPPER: encoding: 0 set_min_output_buffer on block 31 to 96000 set_min_output_buffer on block 33 to 96000 set_min_output_buffer on block 35 to 96000 set_min_output_buffer on block 36 to 96000 set_min_output_buffer on block 39 to 96000 set_min_output_buffer on block 50 to 96000 >>> Done ``` Any clue of what had gone wrong? The flowgraph just doesn’t execute. Below is my system info. ``` $ cat /etc/debian_version 7.8 $ gcc --version gcc (Debian 4.7.2-5) 4.7.2 Copyright (C) 2012 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There ``` is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ``` $ uname -a Linux sgku2 3.2.0-4-686-pae #1 SMP Debian 3.2.65-1+deb7u2 i686 ``` GNU/Linux ``` $ gnuradio-config-info -v 3.7.6.1 $ file /sbin/init /sbin/init: ELF 32-bit LSB executable, Intel 80386, version 1 ``` (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.26, BuildID[sha1]=0x6f99a4bee43009171bce9fa5457099aafaf2f753, stripped Thank you very much. ---
**Author:** ![activecat\_k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c57346/32.png) [@activecat\_k](https://www.ruby-forum.com/u/activecat_k)\ **Post date:** [April 23, 2015, 4:38pm UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987/6 "2015-04-23T16:38:27Z")
Hi, I made quite some changes during the last days so it might well be the case that I introduced several bugs. Can you please double-check that you are not using the new flow graph with an old version of the module (maybe another copy is still installed somewhere). If the problem still exists then please start the flow graph in a debugger. (I guess it actually seg faults but you don’t see it in GRC). You can use something like gdb python run wifi\_loopback.py and then do a backtrace (bt). See also [https://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsDebugging](https://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsDebugging) Best, Bastian On 04/23/2015 01:33 PM, Activecat wrote: > ``` > >>> Warning: This flow graph may not have flow control: no audio or > OFDM MAPPER: encoding: 0 > > ``` > > Any clue of what had gone wrong? > There is NO > $ file /sbin/init > [mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)\> wrote: > Either python3 is selected by cmake or (maybe) your swig version > \> > \> help → Python’s own help system. > \> ----\> 1 import ieee802\_11 > /usr/local/lib/python2.7/dist-packages/ieee802\_11/ieee802\_11\_swig.py > \> 20 if fp is not None: > \> > \> \> name ‘ieee802\_11’ is not defined > > ``` > -- > Dipl.-Inform. Bastian B. > Distributed Embedded Systems Group > University of Paderborn, Germany > http://www.ccs-labs.org/~bloessl/ > > ``` – Dipl.-Inform. Bastian B. Distributed Embedded Systems Group University of Paderborn, Germany > **[Home](https://www.bastibl.net/)** > > I'm Bastian Bloessl, a Research Group Leader at the Secure Mobile Networking Lab, TU Darmstadt. Checkout my blog, projects, publications, and resume; or connect on Github, Twitter, YouTube, or Facebook. ---
**Author:** ![activecat\_k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c57346/32.png) [@activecat\_k](https://www.ruby-forum.com/u/activecat_k)\ **Post date:** [April 24, 2015, 3:02am UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987/7 "2015-04-24T03:02:07Z")
Dear Bastian, I have just downloaded the latest gr-ieee802-11, recompiled and reinstalled. I am using the latest version of the flowgraph. Just that the gnuradio was the one installed at January 2015. Below is the debugging message. ``` (gdb) run wifi_loopback.py Starting program: /usr/bin/python wifi_loopback.py [Thread debugging using libthread_db enabled] Using host libthread_db library ``` “/lib/i386-linux-gnu/i686/cmov/libthread\_db.so.1”. linux; GNU C++ version 4.7.2; Boost\_104900; UHD\_003.008.001-121-gebe7169d ``` [New Thread 0xaecc0b70 (LWP 4846)] [New Thread 0xad5c1b70 (LWP 4847)] Using Volk machine: avx_32_mmx_orc [New Thread 0xa668cb70 (LWP 4848)] OFDM MAPPER: encoding: 0 set_min_output_buffer on block 31 to 96000 set_min_output_buffer on block 33 to 96000 set_min_output_buffer on block 35 to 96000 set_min_output_buffer on block 36 to 96000 set_min_output_buffer on block 39 to 96000 set_min_output_buffer on block 50 to 96000 [New Thread 0xa397ab70 (LWP 4849)] [New Thread 0x95dd8b70 (LWP 4850)] [New Thread 0x955d7b70 (LWP 4851)] [New Thread 0x94dd6b70 (LWP 4852)] [New Thread 0x945d5b70 (LWP 4853)] [New Thread 0x93dd4b70 (LWP 4854)] [New Thread 0x935d3b70 (LWP 4855)] [New Thread 0x92dd2b70 (LWP 4856)] [New Thread 0x925d1b70 (LWP 4857)] [New Thread 0x91dd0b70 (LWP 4858)] [New Thread 0x915cfb70 (LWP 4859)] [New Thread 0x90dceb70 (LWP 4860)] [New Thread 0x905cdb70 (LWP 4861)] [New Thread 0x8fdccb70 (LWP 4862)] [New Thread 0x8f5cbb70 (LWP 4863)] [New Thread 0x8edcab70 (LWP 4864)] [New Thread 0x8e5c9b70 (LWP 4865)] [New Thread 0x8ddc8b70 (LWP 4866)] [New Thread 0x8d5c7b70 (LWP 4867)] [New Thread 0x8cdc6b70 (LWP 4868)] [New Thread 0x8c5c5b70 (LWP 4869)] [New Thread 0x8bdc4b70 (LWP 4870)] [New Thread 0x8b5c3b70 (LWP 4871)] [New Thread 0x8adc2b70 (LWP 4872)] [New Thread 0x8a5c1b70 (LWP 4873)] [New Thread 0x89dc0b70 (LWP 4874)] [New Thread 0x895bfb70 (LWP 4875)] [New Thread 0x88dbeb70 (LWP 4876)] [New Thread 0x885bdb70 (LWP 4877)] [New Thread 0x87dbcb70 (LWP 4878)] [New Thread 0x875bbb70 (LWP 4879)] [New Thread 0x86dbab70 (LWP 4880)] [New Thread 0x865b9b70 (LWP 4881)] [New Thread 0x85db8b70 (LWP 4882)] [New Thread 0x855b7b70 (LWP 4883)] [New Thread 0x84db6b70 (LWP 4884)] [New Thread 0x845b5b70 (LWP 4885)] [New Thread 0x83db4b70 (LWP 4886)] [New Thread 0x835b3b70 (LWP 4887)] [New Thread 0x82db2b70 (LWP 4888)] [New Thread 0x825b1b70 (LWP 4889)] [New Thread 0x81db0b70 (LWP 4890)] [New Thread 0x815afb70 (LWP 4891)] [New Thread 0x80daeb70 (LWP 4892)] [New Thread 0x805adb70 (LWP 4893)] [New Thread 0x7fdacb70 (LWP 4894)] [New Thread 0x7f5abb70 (LWP 4895)] [New Thread 0x7edaab70 (LWP 4896)] [New Thread 0x7e5a9b70 (LWP 4897)] [New Thread 0x7dda8b70 (LWP 4898)] [New Thread 0x7d5a7b70 (LWP 4899)] [New Thread 0x7cda6b70 (LWP 4900)] [New Thread 0x7c5a5b70 (LWP 4901)] [New Thread 0x7bda4b70 (LWP 4902)] Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x815afb70 (LWP 4891)] 0xb2fc302e in ofdm_decode_signal_impl::general_work(int, ``` std::vector\&, std::vector\ \>&, std::vector\ > &) () > from /usr/local/lib/libgnuradio-ieee802\_11.so > (gdb) On Thu, Apr 23, 2015 at 10:36 PM, Bastian B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![activecat\_k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c57346/32.png) [@activecat\_k](https://www.ruby-forum.com/u/activecat_k)\ **Post date:** [January 29, 2015, 9:45am UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987/8 "2015-01-29T09:45:06Z")
Dear Bastian, Yes, this solves all the problems. I just get the current commit and recompile, everything works ! Thank you very much. On Thu, Jan 29, 2015 at 4:20 PM, Bastian B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![activecat\_k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c57346/32.png) [@activecat\_k](https://www.ruby-forum.com/u/activecat_k)\ **Post date:** [April 24, 2015, 10:36am UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987/9 "2015-04-24T10:36:36Z")
On 04/24/2015 03:00 AM, Activecat wrote: > ``` > Program received signal SIGSEGV, Segmentation fault. > [Switching to Thread 0x815afb70 (LWP 4891)] > 0xb2fc302e in ofdm_decode_signal_impl::general_work(int, > > ``` > > std::vector\&, std::vector\ std::allocator\ \>&, std::vector\ > > > &) () > > from /usr/local/lib/libgnuradio-ieee802\_11.so > > (gdb) I think I placed a tag at a wrong offset. I don’t know if this can cause a segfault, but maybe you can try the current version. ---
**Author:** ![activecat\_k](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c57346/32.png) [@activecat\_k](https://www.ruby-forum.com/u/activecat_k)\ **Post date:** [April 24, 2015, 7:34am UTC](https://www.ruby-forum.com/t/re-asking-help-about-gr-ieee802-11/233987/10 "2015-04-24T07:34:13Z")
Hi, > On 24 Apr 2015, at 03:00, Activecat [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > I have just downloaded the latest gr-ieee802-11, recompiled and reinstalled. > I am using the latest version of the flowgraph. Just that the gnuradio was the > one installed at January 2015. > Below is the debugging message. The important thing is that you uninstalled everything from previous installations (I’m asking since several other people experienced segfaults because of that ). > ``` > Program received signal SIGSEGV, Segmentation fault. > [Switching to Thread 0x815afb70 (LWP 4891)] > 0xb2fc302e in ofdm_decode_signal_impl::general_work(int, std::vector > ``` std::allocator \>&, std::vector\ \>&, std::vector\ \>&) () > ``` > from /usr/local/lib/libgnuradio-ieee802_11.so > (gdb) > > ``` This is more of less the only block I did not change -.- It would be very helpful if you could do a debug build (configure in cmake) and then do a backtrace in gdb. Best, Bastian > gdb python > > “/home/sgku/download/zz-downloaded/gr-ieee802-11/examples/wifi\_loopback.py” > Using Volk machine: avx\_32\_mmx\_orc > > ``` > This is free software; see the source for copying conditions. > > ``` > > On Thu, Jan 29, 2015 at 4:30 PM, Activecat \<[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > > ``` > > I really appreciate your help. > > %quickref -> Quick reference. > > in () > > > in swig_import_helper() > > > > > Value "ieee802_11.wifi_signal_field()" cannot be evaluated: > > > > ``` > > – > Dipl.-Inform. Bastian B. > Distributed Embedded Systems Group > University of Paderborn, Germany > [Home | Bastian Bloessl](http://www.ccs-labs.org/~bloessl/) – Dipl.-Inform. Bastian B. Distributed Embedded Systems Group University of Paderborn, Germany > **[Home](https://www.bastibl.net/)** > > I'm Bastian Bloessl, a Research Group Leader at the Secure Mobile Networking Lab, TU Darmstadt. Checkout my blog, projects, publications, and resume; or connect on Github, Twitter, YouTube, or Facebook.