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]> 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 <[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 Is there a reason why you used a link to an outdated version of the file 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) >> >> >> >> 2016-02-21 21:51 GMT+09:00 Marcus Müller <[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 <[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 >>>> [email protected]https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>> >>>> >>>> >>>> _______________________________________________ >>>> Discuss-gnuradio mailing list >>>> [email protected] >>>> 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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