ipv4_frag.h File Reference

IPv4 fragmentation and reassembly. More...

#include "core/net.h"
#include "ipv4/ipv4.h"

Go to the source code of this file.

Data Structures
struct	Ipv4ReassemblyBuffer
	Reassembly buffer. More...
struct	Ipv4FragDesc
	Fragmented packet descriptor. More...

Macros
#define	IPV4_FRAG_SUPPORT   ENABLED
#define	IPV4_OVERLAPPING_FRAG_SUPPORT   ENABLED
#define	IPV4_FRAG_TICK_INTERVAL   1000
#define	IPV4_MAX_FRAG_DATAGRAMS   4
#define	IPV4_MAX_FRAG_DATAGRAM_SIZE   8192
#define	IPV4_FRAG_TIME_TO_LIVE   15000
#define	IPV4_INFINITY   0xFFFF

Functions
error_t	ipv4FragmentDatagram (NetInterface *interface, const Ipv4PseudoHeader *pseudoHeader, uint16_t id, const NetBuffer *payload, size_t payloadOffset, NetTxAncillary *ancillary)
	Fragment an IPv4 datagram into smaller packets. More...
void	ipv4ReassembleDatagram (NetInterface *interface, const Ipv4Header *packet, size_t length, NetRxAncillary *ancillary)
	IPv4 datagram reassembly algorithm. More...
void	ipv4FragTick (NetInterface *interface)
	Fragment reassembly timeout handler. More...
Ipv4FragDesc *	ipv4SearchFragQueue (NetInterface *interface, const Ipv4Header *packet)
	Search for a matching datagram in the reassembly queue. More...
void	ipv4FlushFragQueue (NetInterface *interface)
	Flush IPv4 reassembly queue. More...
Ipv4HoleDesc *	ipv4FindHole (Ipv4FragDesc *frag, uint16_t offset)
	Retrieve hole descriptor. More...
void	ipv4DumpHoleList (Ipv4FragDesc *frag)
	Dump hole descriptor list. More...

Variables
typedef	__packed_struct
	Hole descriptor. More...
uint16_t	last
uint16_t	next
	Ipv4HoleDesc
systime_t	ipv4FragTickCounter

Detailed Description

IPv4 fragmentation and reassembly.

License

SPDX-License-Identifier: GPL-2.0-or-later

Copyright (C) 2010-2025 Oryx Embedded SARL. All rights reserved.

This file is part of CycloneTCP Open.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

Author

Oryx Embedded SARL (www.oryx-embedded.com)

Version

2.5.0

Definition in file ipv4_frag.h.

Macro Definition Documentation

IPV4_FRAG_SUPPORT

#define IPV4_FRAG_SUPPORT   ENABLED

Definition at line 40 of file ipv4_frag.h.

IPV4_FRAG_TICK_INTERVAL

#define IPV4_FRAG_TICK_INTERVAL   1000

Definition at line 54 of file ipv4_frag.h.

IPV4_FRAG_TIME_TO_LIVE

#define IPV4_FRAG_TIME_TO_LIVE   15000

Definition at line 76 of file ipv4_frag.h.

IPV4_INFINITY

#define IPV4_INFINITY   0xFFFF

Definition at line 82 of file ipv4_frag.h.

IPV4_MAX_FRAG_DATAGRAM_SIZE

#define IPV4_MAX_FRAG_DATAGRAM_SIZE   8192

Definition at line 69 of file ipv4_frag.h.

IPV4_MAX_FRAG_DATAGRAMS

#define IPV4_MAX_FRAG_DATAGRAMS   4

Definition at line 62 of file ipv4_frag.h.

IPV4_OVERLAPPING_FRAG_SUPPORT

#define IPV4_OVERLAPPING_FRAG_SUPPORT   ENABLED

Definition at line 47 of file ipv4_frag.h.

Function Documentation

ipv4DumpHoleList()

void ipv4DumpHoleList

(

Ipv4FragDesc *

frag

)

Dump hole descriptor list.

Parameters

[in]

frag

IPv4 fragment descriptor

Definition at line 694 of file ipv4_frag.c.

ipv4FindHole()

Ipv4HoleDesc* ipv4FindHole	(	Ipv4FragDesc *	frag,
		uint16_t	offset
	)

Retrieve hole descriptor.

Parameters

[in]	frag	IPv4 fragment descriptor
[in]	offset	Offset of the hole

Returns

A pointer to the hole descriptor is returned if the specified offset is valid. Otherwise NULL is returned

Definition at line 682 of file ipv4_frag.c.

ipv4FlushFragQueue()

void ipv4FlushFragQueue

(

NetInterface *

interface

)

Flush IPv4 reassembly queue.

Parameters

[in]

interface

Underlying network interface

Definition at line 661 of file ipv4_frag.c.

ipv4FragmentDatagram()

error_t ipv4FragmentDatagram	(	NetInterface *	interface,
		const Ipv4PseudoHeader *	pseudoHeader,
		uint16_t	id,
		const NetBuffer *	payload,
		size_t	payloadOffset,
		NetTxAncillary *	ancillary
	)

Fragment an IPv4 datagram into smaller packets.

Parameters

[in]	interface	Underlying network interface
[in]	pseudoHeader	IPv4 pseudo header
[in]	id	Fragment identification
[in]	payload	Multi-part buffer containing the payload
[in]	payloadOffset	Offset to the first payload byte
[in]	ancillary	Additional options passed to the stack along with the packet

Returns

Error code

Definition at line 72 of file ipv4_frag.c.

ipv4FragTick()

void ipv4FragTick

(

NetInterface *

interface

)

Fragment reassembly timeout handler.

This routine must be periodically called by the TCP/IP stack to handle IPv4 fragment reassembly timeout

Parameters

[in]

interface

Underlying network interface

Definition at line 488 of file ipv4_frag.c.

ipv4ReassembleDatagram()

void ipv4ReassembleDatagram	(	NetInterface *	interface,
		const Ipv4Header *	packet,
		size_t	length,
		NetRxAncillary *	ancillary
	)

IPv4 datagram reassembly algorithm.

Parameters

[in]	interface	Underlying network interface
[in]	packet	Pointer to the IPv4 fragmented packet
[in]	length	Packet length including header and payload
[in]	ancillary	Additional options passed to the stack along with the packet

Definition at line 184 of file ipv4_frag.c.

ipv4SearchFragQueue()

Ipv4FragDesc* ipv4SearchFragQueue	(	NetInterface *	interface,
		const Ipv4Header *	packet
	)

Search for a matching datagram in the reassembly queue.

Parameters

[in]	interface	Underlying network interface
[in]	packet	Incoming IPv4 packet

Returns

Matching fragment descriptor

Definition at line 557 of file ipv4_frag.c.

Variable Documentation

__packed_struct

typedef __packed_struct

Initial value:

{
   uint16_t first

Hole descriptor.

Definition at line 102 of file ipv4_frag.h.

ipv4FragTickCounter

systime_t ipv4FragTickCounter

extern

Definition at line 57 of file ipv4_frag.c.

Ipv4HoleDesc

Ipv4HoleDesc

Definition at line 107 of file ipv4_frag.h.

last

uint16_t last

Definition at line 105 of file ipv4_frag.h.

next

uint16_t next

Definition at line 106 of file ipv4_frag.h.