如何在 C 中打印 ASN.1 UPER 消息字段的字段？

Question

我收到以下消息。这是在 https://asn1.io/asn1playground/ 上创建的基本 ASN.1 Uper 消息。我想用一个字段操作。例如我想打印协议版本。我能怎么做？我可以写 DENM.header.protocol versione 吗？我真的不知道:

value1 DENM ::= {
  header {
    protocolVersion 1,
    messageID denm,
    stationID 1234567
  },
  denm {
    management {
      actionID {
        originatingStationID 20,
        sequenceNumber 30
      },
      detectionTime 45000000000,
      referenceTime oneMillisecAfterUTCStartOf2004,
      eventPosition {
        latitude 40487111,
        longitude -79494789,
        positionConfidenceEllipse {
          semiMajorConfidence 500,
          semiMinorConfidence 400,
          semiMajorOrientation 10
        },
        altitude {
          altitudeValue 2000,
          altitudeConfidence alt-000-02
        }
      },
      validityDuration 600,
      transmissionInterval oneMilliSecond,
      stationType unknown
    },
    situation {
      informationQuality lowest,
      eventType {
        causeCode roadworks,
        subCauseCode 0
      }
    },
    location {
      eventSpeed {
        speedValue standstill,
        speedConfidence equalOrWithinOneCentimeterPerSec
      },
      eventPositionHeading {
        headingValue wgs84North,
        headingConfidence equalOrWithinOneDegree
      },
      traces {
        {
          {
            pathPosition {
              deltaLatitude 20,
              deltaLongitude 20,
              deltaAltitude unavailable
            },
            pathDeltaTime tenMilliSecondsInPast
          },
          {
            pathPosition {
              deltaLatitude 22,
              deltaLongitude 22,
              deltaAltitude unavailable
            }
          }
        }
      },
      roadType urban-NoStructuralSeparationToOppositeLanes
    },
    alacarte {
      impactReduction {
        heightLonCarrLeft oneCentimeter,
        heightLonCarrRight oneCentimeter,
        posLonCarrLeft oneCentimeter,
        posLonCarrRight oneCentimeter,
        positionOfPillars {
          tenCentimeters
        },
        posCentMass unavailable,
        wheelBaseVehicle tenCentimeters,
        turningRadius point4Meters,
        posFrontAx tenCentimeters,
        positionOfOccupants '11111110000000100001'B,
        vehicleMass 20,
        requestResponseIndication response
      },
      externalTemperature oneDegreeCelsius,
      roadWorks {
        lightBarSirenInUse '11'B,
        closedLanes {
          innerhardShoulderStatus availableForStopping,
          drivingLaneStatus '011'B
        },
        restriction {
          unknown
        },
        speedLimit 20,
        incidentIndication {
          causeCode reserved,
          subCauseCode 0
        },
        recommendedPath {
          {
            latitude 20,
            longitude 20,
            positionConfidenceEllipse {
              semiMajorConfidence oneCentimeter,
              semiMinorConfidence oneCentimeter,
              semiMajorOrientation wgs84North
            },
            altitude {
              altitudeValue 200,
              altitudeConfidence alt-000-02
            }
          }
        }
      },
      positioningSolution noPositioningSolution,
      stationaryVehicle {
        stationarySince equalOrGreater15Minutes,
        stationaryCause {
          causeCode roadworks,
          subCauseCode 0
        },
        numberOfOccupants 30,
        vehicleIdentification {
          wMInumber "WVW",
          vDS "ZZZ1JZ"
        },
        energyStorageType '0000010'B
      }
    }
  }
}

如何在 C 中打印字段“PROTOCOL VERSION”？感谢您的帮助！

Answer 1

该网站具有三个基本区域。左侧是您的架构所在的位置。中间区域是您放置问题中包含的 ASN.1 值的地方。右侧是网站输出 ASN.1 可以为该 ASN.1 值创建的各种不同的有线格式（或编码）的地方。十六进制只是呈现为十六进制数字对的二进制输出。

您需要做的是使用您自己的 ASN.1 编译来编译架构，例如 this one。这将为您提供大量 C 源代码，其中一些是编译器的库代码，还有一些是编译器生成的，用于将您的模式表示为 C 结构的层次结构。那里会有一个例程，用于从包含该 ASN.1 值的 uPER 编码的二进制文件中解码 DENM。

一旦你掌握了它，编写一个程序来调用那个 DENM uPER 解码器就很简单了，然后 printf("%i\n",denm.header.protocolVersion);

如何在 C 中打印 ASN.1 UPER 消息字段的字段？

How to print field of an ASN.1 UPER message field in C?

c

printf

decode

encode

asn.1