_IP_HEADER Struct Reference

#include <ip.h>

Detailed Description

IP packet header definition

Data Fields

IP_ADDR DestAddress
WORD_VAL FragmentInfo
WORD_VAL HeaderChecksum
WORD_VAL Identification
BYTE Protocol
IP_ADDR SourceAddress
BYTE TimeToLive
WORD_VAL TotalLength
BYTE TypeOfService

Field Documentation



x--- ---- ---- ---- = RF flag: Reserved -x-- ---- ---- ---- = DF flag: Don't fragment. When set to 1, indicates that the datagram should not be fragmented. --x- ---- ---- ---- = MF flag: More Fragments. When set to 0, indicates that this is the last fragment in a message. When set to 1, indicates that more fragments for this message are to come. If no fragmentation is used, then there will always only be one fragment, and this flag will always be 0. ---x xxxx xxxx xxxx = Fragment offset: When fragmentation of a message occurs, this field specifies the the offset, or position, in the overall message where the data in this fragment goes. It is specified in units of 8 bytes (64 bits). The first fragment has an offset of 0.

WORD_VAL _IP_HEADER::HeaderChecksum

WORD_VAL _IP_HEADER::Identification

This field contains a 16 bit value that is common to each of the fragments beloning to a particular message. For datagrams originally sent unfragmented, it is still filled out, so it can be used if the datagram must be fragmented by a router during delivery. This field is used by the recipient to reassemble without accidentally mixing fragments from different messages. This is needed because fragments may arrive from multiple messages mixed together, since IP datagrams can be received out of order from any device.


IP_ADDR _IP_HEADER::SourceAddress



BYTE _IP_HEADER::TypeOfService


The documentation for this struct was generated from the following file:
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