Problem decoding BCCH-DL-SCH-Message PER #61
Comments
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Here's the output witht EMIT_ASN_DEBUG set to 1:
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Ok, after more investigation I noticed that the binary file I used was mangled. It should be 49 bytes long, but was 64 bytes long. This is the debug output I'm getting when decoding it: $ ./progname -iper -oxer -dd ~/bcch-dl-sch.uper CHOICE BCCH-DL-SCH-MessageType got index 0 in range 1 (constr_CHOICE.c:864) CHOICE c1 got index 0 in range 1 (constr_CHOICE.c:864) CHOICE criticalExtensions got index 0 in range 1 (constr_CHOICE.c:864) Read in presence bitmap for SystemInformation-r8-IEs of 1 bits (0..) (constr_SEQUENCE.c:1073) Preparing to fetch 1+1 elements from sib-TypeAndInfo (constr_SET_OF.c:905) CHOICE CHOICE got index 0 in range 4 (constr_CHOICE.c:864) Read in presence bitmap for SystemInformationBlockType2 of 2 bits (0..) (constr_SEQUENCE.c:1073) Member SystemInformationBlockType2->ac-BarringInfo is optional, p=0 (1->2) (constr_SEQUENCE.c:1102) Decoding member rach-ConfigCommon in RadioResourceConfigCommonSIB (constr_SEQUENCE.c:1120) Decoding member preambleInfo in RACH-ConfigCommon (constr_SEQUENCE.c:1120) Read in presence bitmap for preambleInfo of 1 bits (80..) (constr_SEQUENCE.c:1073) Decoded numberOfRA-Preambles = 12 (NativeEnumerated.c:123) Member preambleInfo->preamblesGroupAConfig is optional, p=1 (1->1) (constr_SEQUENCE.c:1102) Decoding member sizeOfRA-PreamblesGroupA in preamblesGroupAConfig (constr_SEQUENCE.c:1120) Decoded sizeOfRA-PreamblesGroupA = 6 (NativeEnumerated.c:123) Decoded messageSizeGroupA = 0 (NativeEnumerated.c:123) Decoded messagePowerOffsetGroupB = 4 (NativeEnumerated.c:123) Decoded powerRampingStep = 1 (NativeEnumerated.c:123) Decoded preambleInitialReceivedTargetPower = 8 (NativeEnumerated.c:123) Decoded PreambleTransMax = 6 (NativeEnumerated.c:123) Decoded ra-ResponseWindowSize = 7 (NativeEnumerated.c:123) Decoded mac-ContentionResolutionTimer = 7 (NativeEnumerated.c:123) Got value 4 + low 1 (INTEGER.c:622) Decoded modificationPeriodCoeff = 0 (NativeEnumerated.c:123) Decoded defaultPagingCycle = 2 (NativeEnumerated.c:123) Decoded nB = 2 (NativeEnumerated.c:123) Got value 184 + low 0 (INTEGER.c:622) Got value 5 + low 0 (INTEGER.c:622) BOOLEAN decoded as FALSE (BOOLEAN.c:260) Got value 11 + low 0 (INTEGER.c:622) Got value 5 + low 0 (INTEGER.c:622) Got value 78 + low -60 (INTEGER.c:622) Got value 1 + low 0 (INTEGER.c:622) Got value 3 + low 1 (INTEGER.c:622) Decoded hoppingMode = 0 (NativeEnumerated.c:123) Got value 22 + low 0 (INTEGER.c:622) BOOLEAN decoded as TRUE (BOOLEAN.c:260) BOOLEAN decoded as FALSE (BOOLEAN.c:260) Got value 0 + low 0 (INTEGER.c:622) BOOLEAN decoded as FALSE (BOOLEAN.c:260) Got value 0 + low 0 (INTEGER.c:622) Decoded deltaPUCCH-Shift = 1 (NativeEnumerated.c:123) Got value 2 + low 0 (INTEGER.c:622) Got value 0 + low 0 (INTEGER.c:622) Got value 10 + low 0 (INTEGER.c:622) CHOICE SoundingRS-UL-ConfigCommon got index 1 in range 1 (constr_CHOICE.c:864) Read in presence bitmap for setup of 1 bits (0..) (constr_SEQUENCE.c:1073) Decoded srs-BandwidthConfig = 3 (NativeEnumerated.c:123) Decoded srs-SubframeConfig = 7 (NativeEnumerated.c:123) BOOLEAN decoded as TRUE (BOOLEAN.c:260) Member setup->srs-MaxUpPts is optional, p=0 (1->1) (constr_SEQUENCE.c:1102) Got value 59 + low -126 (INTEGER.c:622) Decoded Alpha-r12 = 4 (NativeEnumerated.c:123) Got value 22 + low -127 (INTEGER.c:622) Decoded deltaF-PUCCH-Format1 = 1 (NativeEnumerated.c:123) Decoded deltaF-PUCCH-Format1b = 1 (NativeEnumerated.c:123) Decoded deltaF-PUCCH-Format2 = 2 (NativeEnumerated.c:123) Decoded deltaF-PUCCH-Format2a = 2 (NativeEnumerated.c:123) Decoded deltaF-PUCCH-Format2b = 2 (NativeEnumerated.c:123) Got value 5 + low -1 (INTEGER.c:622) Decoded UL-CyclicPrefixLength = 0 (NativeEnumerated.c:123) Decoding member t300 in UE-TimersAndConstants (constr_SEQUENCE.c:1120) Decoded t300 = 1 (NativeEnumerated.c:123) Decoded t301 = 1 (NativeEnumerated.c:123) Decoded t310 = 5 (NativeEnumerated.c:123) Decoded n310 = 6 (NativeEnumerated.c:123) Decoded t311 = 3 (NativeEnumerated.c:123) Decoded n311 = 0 (NativeEnumerated.c:123) Read in presence bitmap for freqInfo of 2 bits (40..) (constr_SEQUENCE.c:1073) Member freqInfo->ul-CarrierFreq is optional, p=0 (1->2) (constr_SEQUENCE.c:1102) Member freqInfo->ul-Bandwidth is optional, p=1 (2->2) (constr_SEQUENCE.c:1102) Decoded ul-Bandwidth = 3 (NativeEnumerated.c:123) Got value 0 + low 1 (INTEGER.c:622) Member SystemInformationBlockType2->mbsfn-SubframeConfigList is optional, p=0 (2->2) (constr_SEQUENCE.c:1102) Decoded TimeAlignmentTimer = 6 (NativeEnumerated.c:123) CHOICE CHOICE got index 1 in range 4 (constr_CHOICE.c:864) Decoding member cellReselectionInfoCommon in SystemInformationBlockType3 (constr_SEQUENCE.c:1120) Read in presence bitmap for cellReselectionInfoCommon of 1 bits (80..) (constr_SEQUENCE.c:1073) Decoded q-Hyst = 6 (NativeEnumerated.c:123) Member cellReselectionInfoCommon->speedStateReselectionPars is optional, p=1 (1->1) (constr_SEQUENCE.c:1102) Decoded t-Evaluation = 1 (NativeEnumerated.c:123) Decoded t-HystNormal = 0 (NativeEnumerated.c:123) Got value 3 + low 1 (INTEGER.c:622) Got value 7 + low 1 (INTEGER.c:622) Decoded sf-Medium = 3 (NativeEnumerated.c:123) Decoded sf-High = 3 (NativeEnumerated.c:123) Read in presence bitmap for cellReselectionServingFreqInfo of 1 bits (80..) (constr_SEQUENCE.c:1073) Member cellReselectionServingFreqInfo->s-NonIntraSearch is optional, p=1 (1->1) (constr_SEQUENCE.c:1102) Got value 9 + low 0 (INTEGER.c:622) Got value 7 + low 0 (INTEGER.c:622) Got value 7 + low 0 (INTEGER.c:622) Read in presence bitmap for intraFreqCellReselectionInfo of 4 bits (50..) (constr_SEQUENCE.c:1073) Got value 6 + low -70 (INTEGER.c:622) Member intraFreqCellReselectionInfo->p-Max is optional, p=0 (1->4) (constr_SEQUENCE.c:1102) Member intraFreqCellReselectionInfo->s-IntraSearch is optional, p=1 (2->4) (constr_SEQUENCE.c:1102) Got value 29 + low 0 (INTEGER.c:622) Member intraFreqCellReselectionInfo->allowedMeasBandwidth is optional, p=0 (3->4) (constr_SEQUENCE.c:1102) PresenceAntennaPort1 decoded as FALSE (BOOLEAN.c:260) Decoding member t-ReselectionEUTRA in intraFreqCellReselectionInfo (constr_SEQUENCE.c:1120) Got value 1 + low 0 (INTEGER.c:622) Member intraFreqCellReselectionInfo->t-ReselectionEUTRA-SF is optional, p=1 (4->4) (constr_SEQUENCE.c:1102) Decoded sf-Medium = 3 (NativeEnumerated.c:123) Decoded sf-High = 2 (NativeEnumerated.c:123) l=2 (per_support.c:204) Read in extensions bitmap for SystemInformationBlockType3 of 2 bits (40..) (constr_SEQUENCE.c:1158) Decoding member s-IntraSearch-v920 in SystemInformationBlockType3 (nil) (constr_SEQUENCE.c:1186) Getting open type s-IntraSearch-v920 encoded in 4 bytes (per_opentype.c:96)
sib-TypeAndInfo SET OF CHOICE decoded 2, 0x1a5d990 (constr_SET_OF.c:928) It decodes SIB2 but fails at SIB3. |
Using ASN.1 from https://anonsvn.wireshark.org/wireshark/trunk/asn1/lte-rrc/EUTRA-RRC-Definitions.asn I generate file for the converter (with -gen-PER and -fcompound-names flags), then build converter sample with:
I try to decode data:
(binary file here: https://www.dropbox.com/s/o13dyoff18y0xnu/bcch-dl-sch.per?dl=0) by executing the resulting progname. I'm getting:
I investigated it a bit, and it fails in per_get_few_bits(), trying to read from data that has zero bits left. Stack at that point looks like:
So it looks like it tries to decode SIB17, however when I use http://www.marben-products.com/cgi-bin/asn1tools/free-online-asn1-decoder.pl (direct input), I get valid SIB2 and SIB3.
It looks like per_get_few_bits has read only 25 bits out of the 64-bit file. Could you help investigate whether the problem is in asn1c or the EUTRA-RRC-Definitions.asn code?
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