Namespace inet

Ipv4Header

class

C++ definition

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)
checksum	uint16_t	@byte(2)
checksumMode	ChecksumMode
srcAddress	Ipv4Address
destAddress	Ipv4Address
options	TlvOptions	array of option pointers, option pointers owned by datagram

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 checksum = 0;    // @byte(2)
    ChecksumMode checksumMode = CHECKSUM_MODE_UNDEFINED;

    Ipv4Address srcAddress;

    Ipv4Address destAddress;

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

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