ip6_frag.c File Reference

IPv6 fragmentation and reassembly.

#include "lwip/opt.h"
#include "lwip/ip6_frag.h"
#include "lwip/ip6.h"
#include "lwip/icmp6.h"
#include "lwip/nd6.h"
#include "lwip/ip.h"
#include "lwip/pbuf.h"
#include "lwip/memp.h"
#include "lwip/stats.h"
#include <string.h>

Data Structures
struct	ip6_reass_helper
	This is a helper struct which holds the starting offset and the ending offset of this fragment to easily chain the fragments. More...

Macros
#define	IP_REASS_CHECK_OVERLAP   1
	Setting this to 0, you can turn off checking the fragments for overlapping regions. More...
#define	IP_REASS_FLAG_LASTFRAG   0x01
#define	IP_REASS_FREE_OLDEST   1
	Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is full (IP_REASS_MAX_PBUFS pbufs are enqueued). More...

Functions
struct pbuf *	ip6_reass (struct pbuf *p)
	Reassembles incoming IPv6 fragments into an IPv6 datagram. More...
static void	ip6_reass_free_complete_datagram (struct ip6_reassdata *ipr)
	Free a datagram (struct ip6_reassdata) and all its pbufs. More...
static void	ip6_reass_remove_oldest_datagram (struct ip6_reassdata *ipr, int pbufs_needed)
	Free the oldest datagram to make room for enqueueing new fragments. More...
void	ip6_reass_tmr (void)

Variables
static u16_t	ip6_reass_pbufcount
PACK_STRUCT_BEGIN struct ip6_reass_helper	PACK_STRUCT_STRUCT
static PACK_STRUCT_END struct ip6_reassdata *	reassdatagrams

#define IP_REASS_CHECK_OVERLAP   1

Setting this to 0, you can turn off checking the fragments for overlapping regions.

The code gets a little smaller. Only use this if you know that overlapping won't occur on your network!

#define IP_REASS_FLAG_LASTFRAG   0x01

#define IP_REASS_FREE_OLDEST   1

Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is full (IP_REASS_MAX_PBUFS pbufs are enqueued).

The code gets a little smaller. Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA is set to 1, so one datagram can be reassembled at a time, only.

struct pbuf* ip6_reass

(

struct pbuf *

p

)

Reassembles incoming IPv6 fragments into an IPv6 datagram.

Parameters

p	points to the IPv6 Fragment Header
len	the length of the payload (after Fragment Header)

Returns

NULL if reassembly is incomplete, pbuf pointing to IPv6 Header if reassembly is complete

References ip6_reassdata::datagram_len, htons, ip6_reassdata::identification, if(), ip6_addr_cmp, ip6_current_dest_addr, ip6_current_header, ip6_current_src_addr, IP6_FRAG_HLEN, IP6_FRAG_MORE_FLAG, IP6_FRAG_OFFSET_MASK, IP6_FRAG_STATS_INC, IP6_HLEN, ip6_reass_pbufcount, ip6_reass_remove_oldest_datagram(), ip6_reassdata::iphdr, LWIP_ASSERT, memp_free(), memp_malloc(), ip6_reassdata::next, ip6_reassdata::nexth, ntohs, NULL, ip6_reassdata::p, pbuf::payload, pbuf_cat(), pbuf_clen(), pbuf_free(), pbuf_header(), reassdatagrams, and ip6_reassdata::timer.

Referenced by ip6_input().

static void ip6_reass_free_complete_datagram ( struct ip6_reassdata *  ipr )

static

Free a datagram (struct ip6_reassdata) and all its pbufs.

Updates the total count of enqueued pbufs (ip6_reass_pbufcount), sends an ICMP time exceeded packet.

Parameters

ipr	datagram to free

References ICMP6_TE_FRAG, icmp6_time_exceeded(), if(), ip6_reass_pbufcount, ip6_reassdata::iphdr, LWIP_ASSERT, memp_free(), ip6_reassdata::next, NULL, ip6_reassdata::p, pbuf::payload, pbuf_clen(), pbuf_free(), pbuf_header(), and reassdatagrams.

Referenced by ip6_reass_remove_oldest_datagram(), and ip6_reass_tmr().

static void ip6_reass_remove_oldest_datagram ( struct ip6_reassdata *  ipr, int  pbufs_needed  )

static

Free the oldest datagram to make room for enqueueing new fragments.

The datagram ipr is not freed!

Parameters

ipr	ip6_reassdata for the current fragment
pbufs_needed	number of pbufs needed to enqueue (used for freeing other datagrams if not enough space)

References ip6_reass_free_complete_datagram(), ip6_reass_pbufcount, ip6_reassdata::next, NULL, reassdatagrams, and ip6_reassdata::timer.

Referenced by ip6_reass().

void ip6_reass_tmr

(

void

)

References ip6_reass_free_complete_datagram(), ip6_reassdata::next, NULL, reassdatagrams, and ip6_reassdata::timer.

Referenced by ip6_reass_timer().

u16_t ip6_reass_pbufcount

static

Referenced by ip6_reass(), ip6_reass_free_complete_datagram(), and ip6_reass_remove_oldest_datagram().

PACK_STRUCT_BEGIN struct ip6_reass_helper PACK_STRUCT_STRUCT

PACK_STRUCT_END struct ip6_reassdata* reassdatagrams

static

Referenced by ip6_reass(), ip6_reass_free_complete_datagram(), ip6_reass_remove_oldest_datagram(), and ip6_reass_tmr().