Hi, yes, packet_decoder calls crc_check consequently. My receiver get text(ex/ “HELLO WORLD”) from message sent by sender
I expected only when expected==actual is “true”, it get text else(“false”) receiver discard this packet so doesn’t get any text However, although crc_check return “false”, receiver get text without interruption. I don’t know why receiver do not discard the “false” packet. Thanks for every replies. > 2016. 2. 22., 오전 12:30, Marcus Müller <[email protected]> 작성: > > Hi Jawad, > > ahhh you're right, of course! I was missing that the callback actually is set > in the grc xml file to a lambda that calls recv_packet, so that's where the > checking whether the CRC was correct happens :) > So, yes, I think the logic involved here is OK, but Sang Hyuk is still seeing > problems. > So: You say packets for which the CRC is not correct still get accepted. What > does "accepted" mean in the context? as far as I can tell, they don't get > inserted into the output message queue: > > def recv_pkt(self, ok, payload): > msg = gr.message_from_string(payload, 0, self._item_size_out, > len(payload)/self._item_size_out) > if ok: self._msgq_out.insert_tail(msg) > > because for them, "ok" is "False". > Do they still appear on the output of the packet decoder? > > > Best regards, > Marcus > > > On 21.02.2016 15:22, Jawad Seddar wrote: >> Hi all, >> >> The packet decoder block uses packet_utils module (namely the >> packet_utils.unmake_packet() function) found in gr-digital. >> >> The crc check occurs in the unmake_packet function. >> >> The logic in that function is correct, what do you think is wrong with >> returning actual == expected? >> >> Regards, >> Jawad >> >> Le 21 févr. 2016 14:26, "Marcus Müller" <[email protected] >> <mailto:[email protected]>> a écrit : >> OK, sadly that means I'm even more confused :( >> packet_decoder doesn't have any CRC checking! >> >> Best regards, >> Marcus >> >> On 21.02.2016 14:20, SangHyuk Kim wrote: >>> No! I'm using current version. the link was just for showing.! >>> >>> 2016-02-21 22:14 GMT+09:00 Marcus Müller < >>> <mailto:[email protected]>[email protected] >>> <mailto:[email protected]>>: >>> Hi, >>> >>> thanks! Now it's clear what you're using :) >>> Is there a reason why you used a link to an outdated version of the file >>> from 2011? >>> >>> Best regards, >>> Marcus >>> >>> >>> On 21.02.2016 14:02, SangHyuk Kim wrote: >>>> I'm using "packet_decoder" ( <http://goo.gl/7uVDDa>http://goo.gl/7uVDDa >>>> <http://goo.gl/7uVDDa>) >>>> >>>> >>>> >>>> 2016-02-21 21:51 GMT+09:00 Marcus Müller < >>>> <mailto:[email protected]>[email protected] >>>> <mailto:[email protected]>>: >>>> Hi, >>>> >>>> the problem is that the string "packet decoding" doesn't appear anywhere >>>> in the current GNU Radio source code, so I'm still not sure which block >>>> you are using. Also, crc.check_crc32 is used in two different blocks, so I >>>> can't even tell this way what we are talking about :( >>>> Can you actually make sure twice you got the letter-for-letter right name >>>> of the "packet decoding" block? >>>> >>>> Best regards, >>>> marcis >>>> >>>> >>>> >>>> On 21.02.2016 13:38, SangHyuk Kim wrote: >>>>> Thank Marcus. >>>>> >>>>> "packet decoding" recovers message from received packet >>>>> >>>>> and i got false from crc.py >>>>> >>>>> def check_crc32(s): >>>>> if len(s) < 4: >>>>> return (False, '') >>>>> msg = s[:-4] >>>>> #print "msg = '%s'" % (msg,) >>>>> actual = digital.crc32(msg) >>>>> (expected,) = struct.unpack(">I", s[-4:]) >>>>> #print "actual =", hex(actual), "expected =", hex(expected) >>>>> print actual == expected >>>>> return (actual == expected, msg) >>>>> >>>>> 2016-02-21 20:52 GMT+09:00 Marcus Müller < >>>>> <mailto:[email protected]>[email protected] >>>>> <mailto:[email protected]>>: >>>>> Dear Sang Hyuk Kim, >>>>> >>>>> what "packet decoding" are you specifically talking about, and could you >>>>> show us the code you've modified? >>>>> >>>>> Best regards, >>>>> Marcus >>>>> >>>>> >>>>> On 21.02.2016 12:32, SangHyuk Kim wrote: >>>>>> Hi, I transmit simple text file using two USRP N210 >>>>>> >>>>>> Tx) >>>>>> file source -> packet encoding -> mod(GMSK) -> usrp sink >>>>>> >>>>>> Rx) >>>>>> usrp source -> demod(GMSK) -> packet decoding -> file sink >>>>>> >>>>>> >>>>>> To make corrupt packet, I tried to modify part of crc check >>>>>> >>>>>> I guess if the crc of received packet doesn't match with original one, >>>>>> receiver would discard the packet. >>>>>> >>>>>> However, I found receiver accepts every packet even if crc check returns >>>>>> 'false'. >>>>>> (I expected receiver accepts packet only pass crc check by 'true') >>>>>> >>>>>> Why it always return false and how can I corrupt packet with other ways >>>>>> ? >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> Discuss-gnuradio mailing list >>>>>> [email protected] <mailto:[email protected]> >>>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>>> <https://lists.gnu.org/mailman/listinfo/discuss-gnuradio> >>>>> >>>>> >>>>> _______________________________________________ >>>>> Discuss-gnuradio mailing list >>>>> <mailto:[email protected]>[email protected] >>>>> <mailto:[email protected]> >>>>> >>>>> <https://lists.gnu.org/mailman/listinfo/discuss-gnuradio>https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>> <https://lists.gnu.org/mailman/listinfo/discuss-gnuradio> >>>>> >>>>> >>>> >>>> >>> >>> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> [email protected] <mailto:[email protected]> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> <https://lists.gnu.org/mailman/listinfo/discuss-gnuradio> >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> [email protected] <mailto:[email protected]> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> <https://lists.gnu.org/mailman/listinfo/discuss-gnuradio> > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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