Data Channel Fragmentation module header file. More...

#include "common.h"
#include "buffer.h"
#include "interval.h"
#include "mtu.h"
#include "shaper.h"
#include "error.h"

Include dependency graph for fragment.h:

This graph shows which files directly or indirectly include this file:

Data Structures
struct	fragment
	Structure for reassembling one incoming fragmented packet. More...

struct	fragment_list
	List of fragment structures for reassembling multiple incoming packets concurrently. More...

struct	fragment_master
	Fragmentation and reassembly state for one VPN tunnel instance. More...

Macros
#define	N_FRAG_BUF 25
	Number of packet buffers for reassembling incoming fragmented packets.

#define	FRAG_TTL_SEC 10
	Time-to-live in seconds for a fragment.

#define	FRAG_WAKEUP_INTERVAL 5
	Interval in seconds between calls to wakeup code.

#define	FRAG_MAP_MASK 0xFFFFFFFF
	Mask for reassembly map.

#define	MAX_FRAGS 32
	Maximum number of fragments per packet.

#define	N_SEQ_ID 256
	One more than the maximum fragment sequence ID, above which the IDs wrap to zero.

#define	MAX_FRAG_PKT_SIZE 65536
	(Not used) Maximum packet size before fragmenting.

Functions
void	fragment_wakeup (struct fragment_master f, struct frame frame)

Functions for initialization and cleanup
struct fragment_master *	fragment_init (struct frame *frame)
	Allocate and initialize a `fragment_master` structure.

void	fragment_frame_init (struct fragment_master f, const struct frame frame)
	Allocate internal packet buffers for a `fragment_master` structure.

void	fragment_free (struct fragment_master *f)
	Free a `fragment_master` structure and its internal packet buffers.

Functions for processing packets received from a remote OpenVPN peer
void	fragment_incoming (struct fragment_master f, struct buffer buf, const struct frame *frame)
	Process an incoming packet, which may or may not be fragmented.

Functions for processing packets to be sent to a remote OpenVPN peer
void	fragment_outgoing (struct fragment_master f, struct buffer buf, const struct frame *frame)
	Process an outgoing packet, which may or may not need to be fragmented.

bool	fragment_ready_to_send (struct fragment_master f, struct buffer buf, const struct frame *frame)
	Check whether outgoing fragments are ready to be send, and if so make one available.

static bool	fragment_outgoing_defined (struct fragment_master *f)
	Check whether a `fragment_master` structure contains fragments ready to be sent.

Functions for regular housekeeping
static void	fragment_housekeeping (struct fragment_master f, struct frame frame, struct timeval *tv)
	Perform housekeeping of a `fragment_master` structure.

Fragment header
Todo: Add description of fragment header format.
#define	hton_fragment_header_type(x) htonl(x)
	Convert a fragment_header_type from host to network order.

#define	ntoh_fragment_header_type(x) ntohl(x)
	Convert a `fragment_header_type` from network to host order.

#define	FRAG_TYPE_MASK 0x00000003
	Bit mask for fragment type info.

#define	FRAG_TYPE_SHIFT 0
	Bit shift for fragment type info.

#define	FRAG_WHOLE 0
	Fragment type indicating packet is whole.

#define	FRAG_YES_NOTLAST 1
	Fragment type indicating packet is part of a fragmented packet, but not the last part in the sequence.

#define	FRAG_YES_LAST 2
	Fragment type indicating packet is the last part in the sequence of parts.

#define	FRAG_TEST 3
	Fragment type not implemented yet.

#define	FRAG_SEQ_ID_MASK 0x000000ff
	Bit mask for fragment sequence ID.

#define	FRAG_SEQ_ID_SHIFT 2
	Bit shift for fragment sequence ID.

#define	FRAG_ID_MASK 0x0000001f
	Bit mask for fragment ID.

#define	FRAG_ID_SHIFT 10
	Bit shift for fragment ID.

#define	FRAG_SIZE_MASK 0x00003fff
	Bit mask for fragment size.

#define	FRAG_SIZE_SHIFT 15
	Bit shift for fragment size.

#define	FRAG_SIZE_ROUND_SHIFT 2
	Bit shift for fragment size rounding.

#define	FRAG_SIZE_ROUND_MASK ((1 << FRAG_SIZE_ROUND_SHIFT) - 1)
	Bit mask for fragment size rounding.

#define	FRAG_EXTRA_MASK 0x0000ffff
	Bit mask for extra bits.

#define	FRAG_EXTRA_SHIFT 15
	Bit shift for extra bits.

typedef uint32_t	fragment_header_type
	Fragmentation information is stored in a 32-bit packet header.

Detailed Description

Data Channel Fragmentation module header file.

Definition in file fragment.h.

Macro Definition Documentation

#define FRAG_MAP_MASK 0xFFFFFFFF

Mask for reassembly map.

Definition at line 72 of file fragment.h.

#define MAX_FRAG_PKT_SIZE 65536

(Not used) Maximum packet size before fragmenting.

Definition at line 156 of file fragment.h.

#define MAX_FRAGS 32

Maximum number of fragments per packet.

Definition at line 73 of file fragment.h.

#define N_SEQ_ID 256

One more than the maximum fragment sequence ID, above which the IDs wrap to zero.

Should be a power of 2.

Definition at line 147 of file fragment.h.