Ipv4Header¶

Namespace: inet

class Ipv4Header

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

Usage diagram¶

Inheritance diagram¶

Extends¶

Name	Type	Description
NetworkHeaderBase	class	(no description)

Fields¶

Name	Type	Description
id	int
mutable	bool
complete	bool
correct	bool
properlyRepresented	bool
chunkLength	b
rawBin	string[]
rawHex	string[]
regionTags	SharingRegionTagSet::TagBaseRegionTag[]
sourceAddress	L3Address
destinationAddress	L3Address
protocol	const Protocol *
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

Properties¶

Name	Value	Description
beforeChange	handleChange()
descriptor	readonly
existingClass
packetData

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