Namespace inet

Ipv4Header

class

Represents an Ipv4 datagram.

Uses the following cPacket fields:

getByteLength() / setByteLength() to represent total datagram length
hasBitError() / setBitError() to represent datagram correctness
getTimestamp() / setTimestamp (simtime) used in timestamp option

Additional length fields defined in this class are in bytes.

Only one of the option fields can exist at a time.

TODO cleanup order of fields

Extends

Name	Type	Description
NetworkHeaderBase	(unknown -- not in documented files)

Fields

Name	Type	Description
chunkLength
version	short	@bit(4)
headerLength	B	@bit(4), bytes, must be multiple of 4
typeOfService	short	@bit(8) OMNeT++ 6.0: short __dscp @custom @getter(getDscp) @setter(setDscp); // @bit(6), maps to bits 0-5 of ToS, stored in typeOfService short __ecn @custom @getter(getEcn) @setter(setEcn); // @bit(2), maps to bits 6-7 of ToS, stored in typeOfService
totalLengthField	B	@byte(2)
identification	uint16_t	@byte(2)
reservedBit	bool	@bit(1)
moreFragments	bool	@bit(1)
dontFragment	bool	@bit(1)
fragmentOffset	uint16_t	@bit(13), must be multiple of 8
timeToLive	short	@byte(1)
protocolId	IpProtocolId	@byte(1)
crc	uint16_t	@byte(2)
crcMode	CrcMode
srcAddress	Ipv4Address
destAddress	Ipv4Address
options	TlvOptions	array of option pointers, option pointers owned by datagram

Packet operations (observed)

action	module
insertAtBack	ApskScalarRadioMedium, PimSm
insertAtFront	Ipv4, Gpsr, SctpCrcInsertion, TcpCrcInsertionHook, Udp, UdpCrcInsertionHook
insertDataAt	DscpMarker, RedDropper
peekAtFront	Icmp, Ipv4, Mpls, PimSm
peekDataAt	ExampleQosClassifier, QosClassifier, Icmp, RedDropper
popAtFront	PcapRecorder, BehaviorAggregateClassifier, DiffservQueue, MultiFieldClassifier, Ipv4, StreamIdentifier, PacketMultiplexer, PimSm, Udp
removeAtFront	Ipv4, Gpsr
removeDataAt	DscpMarker, RedDropper

Source code

//
// Represents an Ipv4 datagram.
//
// Uses the following cPacket fields:
//    - getByteLength() / setByteLength() to represent total datagram length
//    - hasBitError() / setBitError() to represent datagram correctness
//    - getTimestamp() / setTimestamp (simtime) used in timestamp option
//
// Additional length fields defined in this class are in bytes.
//
// Only one of the option fields can exist at a time.
//
// TODO cleanup order of fields
class Ipv4Header extends NetworkHeaderBase
{
    chunkLength = IPv4_MIN_HEADER_LENGTH;

    short version = 4;      // @bit(4)
    B headerLength = IPv4_MIN_HEADER_LENGTH;         // @bit(4), bytes, must be multiple of 4
    short typeOfService;    // @bit(8)
    // OMNeT++ 6.0:
    // short __dscp @custom @getter(getDscp) @setter(setDscp);  // @bit(6), maps to bits 0-5 of ToS, stored in typeOfService
    // short __ecn @custom @getter(getEcn) @setter(setEcn);  // @bit(2),  maps to bits 6-7 of ToS, stored in typeOfService

    B totalLengthField;    // @byte(2)

    uint16_t identification;    // @byte(2)
    bool reservedBit = false;    // @bit(1)
    bool moreFragments;    // @bit(1)
    bool dontFragment;    // @bit(1)
    uint16_t fragmentOffset;         // @bit(13), must be multiple of 8

    short timeToLive;    // @byte(1)
    IpProtocolId protocolId = IP_PROT_NONE;    // @byte(1)
    uint16_t crc = 0;    // @byte(2)
    CrcMode crcMode = CRC_MODE_UNDEFINED;

    Ipv4Address srcAddress;

    Ipv4Address destAddress;

    TlvOptions options; // array of option pointers, option pointers owned by datagram
}

File: src/inet/networklayer/ipv4/Ipv4Header.msg