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Adam Green / Mbed 2 deprecated WeatherStation

Web server based weather station using Sparkfun Weather Meters.

Dependencies: FatFileSystem mbed WeatherMeters SDFileSystem

NetStack/lwip/core/ipv4/ip_frag.c@0:616601bde9fb, 2012-02-23 (annotated)

Committer:: AdamGreen
Date:: Thu Feb 23 21:38:39 2012 +0000
Revision:: 0:616601bde9fb

Who changed what in which revision?

User	Revision	Line number	New contents of line
AdamGreen	0:616601bde9fb	1	/**
AdamGreen	0:616601bde9fb	2	* @file
AdamGreen	0:616601bde9fb	3	* This is the IPv4 packet segmentation and reassembly implementation.
AdamGreen	0:616601bde9fb	4	*
AdamGreen	0:616601bde9fb	5	*/
AdamGreen	0:616601bde9fb	6
AdamGreen	0:616601bde9fb	7	/*
AdamGreen	0:616601bde9fb	8	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
AdamGreen	0:616601bde9fb	9	* All rights reserved.
AdamGreen	0:616601bde9fb	10	*
AdamGreen	0:616601bde9fb	11	* Redistribution and use in source and binary forms, with or without modification,
AdamGreen	0:616601bde9fb	12	* are permitted provided that the following conditions are met:
AdamGreen	0:616601bde9fb	13	*
AdamGreen	0:616601bde9fb	14	* 1. Redistributions of source code must retain the above copyright notice,
AdamGreen	0:616601bde9fb	15	* this list of conditions and the following disclaimer.
AdamGreen	0:616601bde9fb	16	* 2. Redistributions in binary form must reproduce the above copyright notice,
AdamGreen	0:616601bde9fb	17	* this list of conditions and the following disclaimer in the documentation
AdamGreen	0:616601bde9fb	18	* and/or other materials provided with the distribution.
AdamGreen	0:616601bde9fb	19	* 3. The name of the author may not be used to endorse or promote products
AdamGreen	0:616601bde9fb	20	* derived from this software without specific prior written permission.
AdamGreen	0:616601bde9fb	21	*
AdamGreen	0:616601bde9fb	22	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
AdamGreen	0:616601bde9fb	23	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
AdamGreen	0:616601bde9fb	24	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
AdamGreen	0:616601bde9fb	25	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
AdamGreen	0:616601bde9fb	26	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
AdamGreen	0:616601bde9fb	27	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
AdamGreen	0:616601bde9fb	28	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
AdamGreen	0:616601bde9fb	29	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
AdamGreen	0:616601bde9fb	30	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
AdamGreen	0:616601bde9fb	31	* OF SUCH DAMAGE.
AdamGreen	0:616601bde9fb	32	*
AdamGreen	0:616601bde9fb	33	* This file is part of the lwIP TCP/IP stack.
AdamGreen	0:616601bde9fb	34	*
AdamGreen	0:616601bde9fb	35	* Author: Jani Monoses <jani@iv.ro>
AdamGreen	0:616601bde9fb	36	* Simon Goldschmidt
AdamGreen	0:616601bde9fb	37	* original reassembly code by Adam Dunkels <adam@sics.se>
AdamGreen	0:616601bde9fb	38	*
AdamGreen	0:616601bde9fb	39	*/
AdamGreen	0:616601bde9fb	40
AdamGreen	0:616601bde9fb	41	#include "lwip/opt.h"
AdamGreen	0:616601bde9fb	42	#include "lwip/ip_frag.h"
AdamGreen	0:616601bde9fb	43	#include "lwip/def.h"
AdamGreen	0:616601bde9fb	44	#include "lwip/inet_chksum.h"
AdamGreen	0:616601bde9fb	45	#include "lwip/netif.h"
AdamGreen	0:616601bde9fb	46	#include "lwip/snmp.h"
AdamGreen	0:616601bde9fb	47	#include "lwip/stats.h"
AdamGreen	0:616601bde9fb	48	#include "lwip/icmp.h"
AdamGreen	0:616601bde9fb	49
AdamGreen	0:616601bde9fb	50	#include <string.h>
AdamGreen	0:616601bde9fb	51
AdamGreen	0:616601bde9fb	52	#if IP_REASSEMBLY
AdamGreen	0:616601bde9fb	53	/**
AdamGreen	0:616601bde9fb	54	* The IP reassembly code currently has the following limitations:
AdamGreen	0:616601bde9fb	55	* - IP header options are not supported
AdamGreen	0:616601bde9fb	56	* - fragments must not overlap (e.g. due to different routes),
AdamGreen	0:616601bde9fb	57	* currently, overlapping or duplicate fragments are thrown away
AdamGreen	0:616601bde9fb	58	* if IP_REASS_CHECK_OVERLAP=1 (the default)!
AdamGreen	0:616601bde9fb	59	*
AdamGreen	0:616601bde9fb	60	* @todo: work with IP header options
AdamGreen	0:616601bde9fb	61	*/
AdamGreen	0:616601bde9fb	62
AdamGreen	0:616601bde9fb	63	/** Setting this to 0, you can turn off checking the fragments for overlapping
AdamGreen	0:616601bde9fb	64	* regions. The code gets a little smaller. Only use this if you know that
AdamGreen	0:616601bde9fb	65	* overlapping won't occur on your network! */
AdamGreen	0:616601bde9fb	66	#ifndef IP_REASS_CHECK_OVERLAP
AdamGreen	0:616601bde9fb	67	#define IP_REASS_CHECK_OVERLAP 1
AdamGreen	0:616601bde9fb	68	#endif /* IP_REASS_CHECK_OVERLAP */
AdamGreen	0:616601bde9fb	69
AdamGreen	0:616601bde9fb	70	/** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
AdamGreen	0:616601bde9fb	71	* full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
AdamGreen	0:616601bde9fb	72	* Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
AdamGreen	0:616601bde9fb	73	* is set to 1, so one datagram can be reassembled at a time, only. */
AdamGreen	0:616601bde9fb	74	#ifndef IP_REASS_FREE_OLDEST
AdamGreen	0:616601bde9fb	75	#define IP_REASS_FREE_OLDEST 1
AdamGreen	0:616601bde9fb	76	#endif /* IP_REASS_FREE_OLDEST */
AdamGreen	0:616601bde9fb	77
AdamGreen	0:616601bde9fb	78	#define IP_REASS_FLAG_LASTFRAG 0x01
AdamGreen	0:616601bde9fb	79
AdamGreen	0:616601bde9fb	80	/** This is a helper struct which holds the starting
AdamGreen	0:616601bde9fb	81	* offset and the ending offset of this fragment to
AdamGreen	0:616601bde9fb	82	* easily chain the fragments.
AdamGreen	0:616601bde9fb	83	* It has the same packing requirements as the IP header, since it replaces
AdamGreen	0:616601bde9fb	84	* the IP header in memory in incoming fragments (after copying it) to keep
AdamGreen	0:616601bde9fb	85	* track of the various fragments. (-> If the IP header doesn't need packing,
AdamGreen	0:616601bde9fb	86	* this struct doesn't need packing, too.)
AdamGreen	0:616601bde9fb	87	*/
AdamGreen	0:616601bde9fb	88	#ifdef PACK_STRUCT_USE_INCLUDES
AdamGreen	0:616601bde9fb	89	# include "arch/bpstruct.h"
AdamGreen	0:616601bde9fb	90	#endif
AdamGreen	0:616601bde9fb	91	PACK_STRUCT_BEGIN
AdamGreen	0:616601bde9fb	92	struct ip_reass_helper {
AdamGreen	0:616601bde9fb	93	PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
AdamGreen	0:616601bde9fb	94	PACK_STRUCT_FIELD(u16_t start);
AdamGreen	0:616601bde9fb	95	PACK_STRUCT_FIELD(u16_t end);
AdamGreen	0:616601bde9fb	96	} PACK_STRUCT_STRUCT;
AdamGreen	0:616601bde9fb	97	PACK_STRUCT_END
AdamGreen	0:616601bde9fb	98	#ifdef PACK_STRUCT_USE_INCLUDES
AdamGreen	0:616601bde9fb	99	# include "arch/epstruct.h"
AdamGreen	0:616601bde9fb	100	#endif
AdamGreen	0:616601bde9fb	101
AdamGreen	0:616601bde9fb	102	#define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB) \
AdamGreen	0:616601bde9fb	103	(ip_addr_cmp(&(iphdrA)->src, &(iphdrB)->src) && \
AdamGreen	0:616601bde9fb	104	ip_addr_cmp(&(iphdrA)->dest, &(iphdrB)->dest) && \
AdamGreen	0:616601bde9fb	105	IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0
AdamGreen	0:616601bde9fb	106
AdamGreen	0:616601bde9fb	107	/* global variables */
AdamGreen	0:616601bde9fb	108	static struct ip_reassdata *reassdatagrams;
AdamGreen	0:616601bde9fb	109	static u16_t ip_reass_pbufcount;
AdamGreen	0:616601bde9fb	110
AdamGreen	0:616601bde9fb	111	/* function prototypes */
AdamGreen	0:616601bde9fb	112	static void ip_reass_dequeue_datagram(struct ip_reassdata ipr, struct ip_reassdata prev);
AdamGreen	0:616601bde9fb	113	static int ip_reass_free_complete_datagram(struct ip_reassdata ipr, struct ip_reassdata prev);
AdamGreen	0:616601bde9fb	114
AdamGreen	0:616601bde9fb	115	/**
AdamGreen	0:616601bde9fb	116	* Reassembly timer base function
AdamGreen	0:616601bde9fb	117	* for both NO_SYS == 0 and 1 (!).
AdamGreen	0:616601bde9fb	118	*
AdamGreen	0:616601bde9fb	119	* Should be called every 1000 msec (defined by IP_TMR_INTERVAL).
AdamGreen	0:616601bde9fb	120	*/
AdamGreen	0:616601bde9fb	121	void
AdamGreen	0:616601bde9fb	122	ip_reass_tmr(void)
AdamGreen	0:616601bde9fb	123	{
AdamGreen	0:616601bde9fb	124	struct ip_reassdata r, prev = NULL;
AdamGreen	0:616601bde9fb	125
AdamGreen	0:616601bde9fb	126	r = reassdatagrams;
AdamGreen	0:616601bde9fb	127	while (r != NULL) {
AdamGreen	0:616601bde9fb	128	/* Decrement the timer. Once it reaches 0,
AdamGreen	0:616601bde9fb	129	* clean up the incomplete fragment assembly */
AdamGreen	0:616601bde9fb	130	if (r->timer > 0) {
AdamGreen	0:616601bde9fb	131	r->timer--;
AdamGreen	0:616601bde9fb	132	LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)r->timer));
AdamGreen	0:616601bde9fb	133	prev = r;
AdamGreen	0:616601bde9fb	134	r = r->next;
AdamGreen	0:616601bde9fb	135	} else {
AdamGreen	0:616601bde9fb	136	/* reassembly timed out */
AdamGreen	0:616601bde9fb	137	struct ip_reassdata *tmp;
AdamGreen	0:616601bde9fb	138	LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out\n"));
AdamGreen	0:616601bde9fb	139	tmp = r;
AdamGreen	0:616601bde9fb	140	/* get the next pointer before freeing */
AdamGreen	0:616601bde9fb	141	r = r->next;
AdamGreen	0:616601bde9fb	142	/* free the helper struct and all enqueued pbufs */
AdamGreen	0:616601bde9fb	143	ip_reass_free_complete_datagram(tmp, prev);
AdamGreen	0:616601bde9fb	144	}
AdamGreen	0:616601bde9fb	145	}
AdamGreen	0:616601bde9fb	146	}
AdamGreen	0:616601bde9fb	147
AdamGreen	0:616601bde9fb	148	/**
AdamGreen	0:616601bde9fb	149	* Free a datagram (struct ip_reassdata) and all its pbufs.
AdamGreen	0:616601bde9fb	150	* Updates the total count of enqueued pbufs (ip_reass_pbufcount),
AdamGreen	0:616601bde9fb	151	* SNMP counters and sends an ICMP time exceeded packet.
AdamGreen	0:616601bde9fb	152	*
AdamGreen	0:616601bde9fb	153	* @param ipr datagram to free
AdamGreen	0:616601bde9fb	154	* @param prev the previous datagram in the linked list
AdamGreen	0:616601bde9fb	155	* @return the number of pbufs freed
AdamGreen	0:616601bde9fb	156	*/
AdamGreen	0:616601bde9fb	157	static int
AdamGreen	0:616601bde9fb	158	ip_reass_free_complete_datagram(struct ip_reassdata ipr, struct ip_reassdata prev)
AdamGreen	0:616601bde9fb	159	{
AdamGreen	0:616601bde9fb	160	u16_t pbufs_freed = 0;
AdamGreen	0:616601bde9fb	161	u8_t clen;
AdamGreen	0:616601bde9fb	162	struct pbuf *p;
AdamGreen	0:616601bde9fb	163	struct ip_reass_helper *iprh;
AdamGreen	0:616601bde9fb	164
AdamGreen	0:616601bde9fb	165	LWIP_ASSERT("prev != ipr", prev != ipr);
AdamGreen	0:616601bde9fb	166	if (prev != NULL) {
AdamGreen	0:616601bde9fb	167	LWIP_ASSERT("prev->next == ipr", prev->next == ipr);
AdamGreen	0:616601bde9fb	168	}
AdamGreen	0:616601bde9fb	169
AdamGreen	0:616601bde9fb	170	snmp_inc_ipreasmfails();
AdamGreen	0:616601bde9fb	171	#if LWIP_ICMP
AdamGreen	0:616601bde9fb	172	iprh = (struct ip_reass_helper *)ipr->p->payload;
AdamGreen	0:616601bde9fb	173	if (iprh->start == 0) {
AdamGreen	0:616601bde9fb	174	/* The first fragment was received, send ICMP time exceeded. */
AdamGreen	0:616601bde9fb	175	/* First, de-queue the first pbuf from r->p. */
AdamGreen	0:616601bde9fb	176	p = ipr->p;
AdamGreen	0:616601bde9fb	177	ipr->p = iprh->next_pbuf;
AdamGreen	0:616601bde9fb	178	/* Then, copy the original header into it. */
AdamGreen	0:616601bde9fb	179	SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN);
AdamGreen	0:616601bde9fb	180	icmp_time_exceeded(p, ICMP_TE_FRAG);
AdamGreen	0:616601bde9fb	181	clen = pbuf_clen(p);
AdamGreen	0:616601bde9fb	182	LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
AdamGreen	0:616601bde9fb	183	pbufs_freed += clen;
AdamGreen	0:616601bde9fb	184	pbuf_free(p);
AdamGreen	0:616601bde9fb	185	}
AdamGreen	0:616601bde9fb	186	#endif /* LWIP_ICMP */
AdamGreen	0:616601bde9fb	187
AdamGreen	0:616601bde9fb	188	/* First, free all received pbufs. The individual pbufs need to be released
AdamGreen	0:616601bde9fb	189	separately as they have not yet been chained */
AdamGreen	0:616601bde9fb	190	p = ipr->p;
AdamGreen	0:616601bde9fb	191	while (p != NULL) {
AdamGreen	0:616601bde9fb	192	struct pbuf *pcur;
AdamGreen	0:616601bde9fb	193	iprh = (struct ip_reass_helper *)p->payload;
AdamGreen	0:616601bde9fb	194	pcur = p;
AdamGreen	0:616601bde9fb	195	/* get the next pointer before freeing */
AdamGreen	0:616601bde9fb	196	p = iprh->next_pbuf;
AdamGreen	0:616601bde9fb	197	clen = pbuf_clen(pcur);
AdamGreen	0:616601bde9fb	198	LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
AdamGreen	0:616601bde9fb	199	pbufs_freed += clen;
AdamGreen	0:616601bde9fb	200	pbuf_free(pcur);
AdamGreen	0:616601bde9fb	201	}
AdamGreen	0:616601bde9fb	202	/* Then, unchain the struct ip_reassdata from the list and free it. */
AdamGreen	0:616601bde9fb	203	ip_reass_dequeue_datagram(ipr, prev);
AdamGreen	0:616601bde9fb	204	LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= pbufs_freed);
AdamGreen	0:616601bde9fb	205	ip_reass_pbufcount -= pbufs_freed;
AdamGreen	0:616601bde9fb	206
AdamGreen	0:616601bde9fb	207	return pbufs_freed;
AdamGreen	0:616601bde9fb	208	}
AdamGreen	0:616601bde9fb	209
AdamGreen	0:616601bde9fb	210	#if IP_REASS_FREE_OLDEST
AdamGreen	0:616601bde9fb	211	/**
AdamGreen	0:616601bde9fb	212	* Free the oldest datagram to make room for enqueueing new fragments.
AdamGreen	0:616601bde9fb	213	* The datagram 'fraghdr' belongs to is not freed!
AdamGreen	0:616601bde9fb	214	*
AdamGreen	0:616601bde9fb	215	* @param fraghdr IP header of the current fragment
AdamGreen	0:616601bde9fb	216	* @param pbufs_needed number of pbufs needed to enqueue
AdamGreen	0:616601bde9fb	217	* (used for freeing other datagrams if not enough space)
AdamGreen	0:616601bde9fb	218	* @return the number of pbufs freed
AdamGreen	0:616601bde9fb	219	*/
AdamGreen	0:616601bde9fb	220	static int
AdamGreen	0:616601bde9fb	221	ip_reass_remove_oldest_datagram(struct ip_hdr *fraghdr, int pbufs_needed)
AdamGreen	0:616601bde9fb	222	{
AdamGreen	0:616601bde9fb	223	/* @todo Can't we simply remove the last datagram in the
AdamGreen	0:616601bde9fb	224	* linked list behind reassdatagrams?
AdamGreen	0:616601bde9fb	225	*/
AdamGreen	0:616601bde9fb	226	struct ip_reassdata r, oldest, *prev;
AdamGreen	0:616601bde9fb	227	int pbufs_freed = 0, pbufs_freed_current;
AdamGreen	0:616601bde9fb	228	int other_datagrams;
AdamGreen	0:616601bde9fb	229
AdamGreen	0:616601bde9fb	230	/* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
AdamGreen	0:616601bde9fb	231	* but don't free the datagram that 'fraghdr' belongs to! */
AdamGreen	0:616601bde9fb	232	do {
AdamGreen	0:616601bde9fb	233	oldest = NULL;
AdamGreen	0:616601bde9fb	234	prev = NULL;
AdamGreen	0:616601bde9fb	235	other_datagrams = 0;
AdamGreen	0:616601bde9fb	236	r = reassdatagrams;
AdamGreen	0:616601bde9fb	237	while (r != NULL) {
AdamGreen	0:616601bde9fb	238	if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) {
AdamGreen	0:616601bde9fb	239	/* Not the same datagram as fraghdr */
AdamGreen	0:616601bde9fb	240	other_datagrams++;
AdamGreen	0:616601bde9fb	241	if (oldest == NULL) {
AdamGreen	0:616601bde9fb	242	oldest = r;
AdamGreen	0:616601bde9fb	243	} else if (r->timer <= oldest->timer) {
AdamGreen	0:616601bde9fb	244	/* older than the previous oldest */
AdamGreen	0:616601bde9fb	245	oldest = r;
AdamGreen	0:616601bde9fb	246	}
AdamGreen	0:616601bde9fb	247	}
AdamGreen	0:616601bde9fb	248	if (r->next != NULL) {
AdamGreen	0:616601bde9fb	249	prev = r;
AdamGreen	0:616601bde9fb	250	}
AdamGreen	0:616601bde9fb	251	r = r->next;
AdamGreen	0:616601bde9fb	252	}
AdamGreen	0:616601bde9fb	253	if (oldest != NULL) {
AdamGreen	0:616601bde9fb	254	pbufs_freed_current = ip_reass_free_complete_datagram(oldest, prev);
AdamGreen	0:616601bde9fb	255	pbufs_freed += pbufs_freed_current;
AdamGreen	0:616601bde9fb	256	}
AdamGreen	0:616601bde9fb	257	} while ((pbufs_freed < pbufs_needed) && (other_datagrams > 1));
AdamGreen	0:616601bde9fb	258	return pbufs_freed;
AdamGreen	0:616601bde9fb	259	}
AdamGreen	0:616601bde9fb	260	#endif /* IP_REASS_FREE_OLDEST */
AdamGreen	0:616601bde9fb	261
AdamGreen	0:616601bde9fb	262	/**
AdamGreen	0:616601bde9fb	263	* Enqueues a new fragment into the fragment queue
AdamGreen	0:616601bde9fb	264	* @param fraghdr points to the new fragments IP hdr
AdamGreen	0:616601bde9fb	265	* @param clen number of pbufs needed to enqueue (used for freeing other datagrams if not enough space)
AdamGreen	0:616601bde9fb	266	* @return A pointer to the queue location into which the fragment was enqueued
AdamGreen	0:616601bde9fb	267	*/
AdamGreen	0:616601bde9fb	268	static struct ip_reassdata*
AdamGreen	0:616601bde9fb	269	ip_reass_enqueue_new_datagram(struct ip_hdr *fraghdr, int clen)
AdamGreen	0:616601bde9fb	270	{
AdamGreen	0:616601bde9fb	271	struct ip_reassdata* ipr;
AdamGreen	0:616601bde9fb	272	/* No matching previous fragment found, allocate a new reassdata struct */
AdamGreen	0:616601bde9fb	273	ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
AdamGreen	0:616601bde9fb	274	if (ipr == NULL) {
AdamGreen	0:616601bde9fb	275	#if IP_REASS_FREE_OLDEST
AdamGreen	0:616601bde9fb	276	if (ip_reass_remove_oldest_datagram(fraghdr, clen) >= clen) {
AdamGreen	0:616601bde9fb	277	ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
AdamGreen	0:616601bde9fb	278	}
AdamGreen	0:616601bde9fb	279	if (ipr == NULL)
AdamGreen	0:616601bde9fb	280	#endif /* IP_REASS_FREE_OLDEST */
AdamGreen	0:616601bde9fb	281	{
AdamGreen	0:616601bde9fb	282	IPFRAG_STATS_INC(ip_frag.memerr);
AdamGreen	0:616601bde9fb	283	LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct\n"));
AdamGreen	0:616601bde9fb	284	return NULL;
AdamGreen	0:616601bde9fb	285	}
AdamGreen	0:616601bde9fb	286	}
AdamGreen	0:616601bde9fb	287	memset(ipr, 0, sizeof(struct ip_reassdata));
AdamGreen	0:616601bde9fb	288	ipr->timer = IP_REASS_MAXAGE;
AdamGreen	0:616601bde9fb	289
AdamGreen	0:616601bde9fb	290	/* enqueue the new structure to the front of the list */
AdamGreen	0:616601bde9fb	291	ipr->next = reassdatagrams;
AdamGreen	0:616601bde9fb	292	reassdatagrams = ipr;
AdamGreen	0:616601bde9fb	293	/* copy the ip header for later tests and input */
AdamGreen	0:616601bde9fb	294	/* @todo: no ip options supported? */
AdamGreen	0:616601bde9fb	295	SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN);
AdamGreen	0:616601bde9fb	296	return ipr;
AdamGreen	0:616601bde9fb	297	}
AdamGreen	0:616601bde9fb	298
AdamGreen	0:616601bde9fb	299	/**
AdamGreen	0:616601bde9fb	300	* Dequeues a datagram from the datagram queue. Doesn't deallocate the pbufs.
AdamGreen	0:616601bde9fb	301	* @param ipr points to the queue entry to dequeue
AdamGreen	0:616601bde9fb	302	*/
AdamGreen	0:616601bde9fb	303	static void
AdamGreen	0:616601bde9fb	304	ip_reass_dequeue_datagram(struct ip_reassdata ipr, struct ip_reassdata prev)
AdamGreen	0:616601bde9fb	305	{
AdamGreen	0:616601bde9fb	306
AdamGreen	0:616601bde9fb	307	/* dequeue the reass struct */
AdamGreen	0:616601bde9fb	308	if (reassdatagrams == ipr) {
AdamGreen	0:616601bde9fb	309	/* it was the first in the list */
AdamGreen	0:616601bde9fb	310	reassdatagrams = ipr->next;
AdamGreen	0:616601bde9fb	311	} else {
AdamGreen	0:616601bde9fb	312	/* it wasn't the first, so it must have a valid 'prev' */
AdamGreen	0:616601bde9fb	313	LWIP_ASSERT("sanity check linked list", prev != NULL);
AdamGreen	0:616601bde9fb	314	prev->next = ipr->next;
AdamGreen	0:616601bde9fb	315	}
AdamGreen	0:616601bde9fb	316
AdamGreen	0:616601bde9fb	317	/* now we can free the ip_reass struct */
AdamGreen	0:616601bde9fb	318	memp_free(MEMP_REASSDATA, ipr);
AdamGreen	0:616601bde9fb	319	}
AdamGreen	0:616601bde9fb	320
AdamGreen	0:616601bde9fb	321	/**
AdamGreen	0:616601bde9fb	322	* Chain a new pbuf into the pbuf list that composes the datagram. The pbuf list
AdamGreen	0:616601bde9fb	323	* will grow over time as new pbufs are rx.
AdamGreen	0:616601bde9fb	324	* Also checks that the datagram passes basic continuity checks (if the last
AdamGreen	0:616601bde9fb	325	* fragment was received at least once).
AdamGreen	0:616601bde9fb	326	* @param root_p points to the 'root' pbuf for the current datagram being assembled.
AdamGreen	0:616601bde9fb	327	* @param new_p points to the pbuf for the current fragment
AdamGreen	0:616601bde9fb	328	* @return 0 if invalid, >0 otherwise
AdamGreen	0:616601bde9fb	329	*/
AdamGreen	0:616601bde9fb	330	static int
AdamGreen	0:616601bde9fb	331	ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata ipr, struct pbuf new_p)
AdamGreen	0:616601bde9fb	332	{
AdamGreen	0:616601bde9fb	333	struct ip_reass_helper iprh, iprh_tmp, *iprh_prev=NULL;
AdamGreen	0:616601bde9fb	334	struct pbuf *q;
AdamGreen	0:616601bde9fb	335	u16_t offset,len;
AdamGreen	0:616601bde9fb	336	struct ip_hdr *fraghdr;
AdamGreen	0:616601bde9fb	337	int valid = 1;
AdamGreen	0:616601bde9fb	338
AdamGreen	0:616601bde9fb	339	/* Extract length and fragment offset from current fragment */
AdamGreen	0:616601bde9fb	340	fraghdr = (struct ip_hdr*)new_p->payload;
AdamGreen	0:616601bde9fb	341	len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
AdamGreen	0:616601bde9fb	342	offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
AdamGreen	0:616601bde9fb	343
AdamGreen	0:616601bde9fb	344	/* overwrite the fragment's ip header from the pbuf with our helper struct,
AdamGreen	0:616601bde9fb	345	* and setup the embedded helper structure. */
AdamGreen	0:616601bde9fb	346	/* make sure the struct ip_reass_helper fits into the IP header */
AdamGreen	0:616601bde9fb	347	LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN",
AdamGreen	0:616601bde9fb	348	sizeof(struct ip_reass_helper) <= IP_HLEN);
AdamGreen	0:616601bde9fb	349	iprh = (struct ip_reass_helper*)new_p->payload;
AdamGreen	0:616601bde9fb	350	iprh->next_pbuf = NULL;
AdamGreen	0:616601bde9fb	351	iprh->start = offset;
AdamGreen	0:616601bde9fb	352	iprh->end = offset + len;
AdamGreen	0:616601bde9fb	353
AdamGreen	0:616601bde9fb	354	/* Iterate through until we either get to the end of the list (append),
AdamGreen	0:616601bde9fb	355	* or we find on with a larger offset (insert). */
AdamGreen	0:616601bde9fb	356	for (q = ipr->p; q != NULL;) {
AdamGreen	0:616601bde9fb	357	iprh_tmp = (struct ip_reass_helper*)q->payload;
AdamGreen	0:616601bde9fb	358	if (iprh->start < iprh_tmp->start) {
AdamGreen	0:616601bde9fb	359	/* the new pbuf should be inserted before this */
AdamGreen	0:616601bde9fb	360	iprh->next_pbuf = q;
AdamGreen	0:616601bde9fb	361	if (iprh_prev != NULL) {
AdamGreen	0:616601bde9fb	362	/* not the fragment with the lowest offset */
AdamGreen	0:616601bde9fb	363	#if IP_REASS_CHECK_OVERLAP
AdamGreen	0:616601bde9fb	364	if ((iprh->start < iprh_prev->end) \|\| (iprh->end > iprh_tmp->start)) {
AdamGreen	0:616601bde9fb	365	/* fragment overlaps with previous or following, throw away */
AdamGreen	0:616601bde9fb	366	goto freepbuf;
AdamGreen	0:616601bde9fb	367	}
AdamGreen	0:616601bde9fb	368	#endif /* IP_REASS_CHECK_OVERLAP */
AdamGreen	0:616601bde9fb	369	iprh_prev->next_pbuf = new_p;
AdamGreen	0:616601bde9fb	370	} else {
AdamGreen	0:616601bde9fb	371	/* fragment with the lowest offset */
AdamGreen	0:616601bde9fb	372	ipr->p = new_p;
AdamGreen	0:616601bde9fb	373	}
AdamGreen	0:616601bde9fb	374	break;
AdamGreen	0:616601bde9fb	375	} else if(iprh->start == iprh_tmp->start) {
AdamGreen	0:616601bde9fb	376	/* received the same datagram twice: no need to keep the datagram */
AdamGreen	0:616601bde9fb	377	goto freepbuf;
AdamGreen	0:616601bde9fb	378	#if IP_REASS_CHECK_OVERLAP
AdamGreen	0:616601bde9fb	379	} else if(iprh->start < iprh_tmp->end) {
AdamGreen	0:616601bde9fb	380	/* overlap: no need to keep the new datagram */
AdamGreen	0:616601bde9fb	381	goto freepbuf;
AdamGreen	0:616601bde9fb	382	#endif /* IP_REASS_CHECK_OVERLAP */
AdamGreen	0:616601bde9fb	383	} else {
AdamGreen	0:616601bde9fb	384	/* Check if the fragments received so far have no wholes. */
AdamGreen	0:616601bde9fb	385	if (iprh_prev != NULL) {
AdamGreen	0:616601bde9fb	386	if (iprh_prev->end != iprh_tmp->start) {
AdamGreen	0:616601bde9fb	387	/* There is a fragment missing between the current
AdamGreen	0:616601bde9fb	388	* and the previous fragment */
AdamGreen	0:616601bde9fb	389	valid = 0;
AdamGreen	0:616601bde9fb	390	}
AdamGreen	0:616601bde9fb	391	}
AdamGreen	0:616601bde9fb	392	}
AdamGreen	0:616601bde9fb	393	q = iprh_tmp->next_pbuf;
AdamGreen	0:616601bde9fb	394	iprh_prev = iprh_tmp;
AdamGreen	0:616601bde9fb	395	}
AdamGreen	0:616601bde9fb	396
AdamGreen	0:616601bde9fb	397	/* If q is NULL, then we made it to the end of the list. Determine what to do now */
AdamGreen	0:616601bde9fb	398	if (q == NULL) {
AdamGreen	0:616601bde9fb	399	if (iprh_prev != NULL) {
AdamGreen	0:616601bde9fb	400	/* this is (for now), the fragment with the highest offset:
AdamGreen	0:616601bde9fb	401	* chain it to the last fragment */
AdamGreen	0:616601bde9fb	402	#if IP_REASS_CHECK_OVERLAP
AdamGreen	0:616601bde9fb	403	LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
AdamGreen	0:616601bde9fb	404	#endif /* IP_REASS_CHECK_OVERLAP */
AdamGreen	0:616601bde9fb	405	iprh_prev->next_pbuf = new_p;
AdamGreen	0:616601bde9fb	406	if (iprh_prev->end != iprh->start) {
AdamGreen	0:616601bde9fb	407	valid = 0;
AdamGreen	0:616601bde9fb	408	}
AdamGreen	0:616601bde9fb	409	} else {
AdamGreen	0:616601bde9fb	410	#if IP_REASS_CHECK_OVERLAP
AdamGreen	0:616601bde9fb	411	LWIP_ASSERT("no previous fragment, this must be the first fragment!",
AdamGreen	0:616601bde9fb	412	ipr->p == NULL);
AdamGreen	0:616601bde9fb	413	#endif /* IP_REASS_CHECK_OVERLAP */
AdamGreen	0:616601bde9fb	414	/* this is the first fragment we ever received for this ip datagram */
AdamGreen	0:616601bde9fb	415	ipr->p = new_p;
AdamGreen	0:616601bde9fb	416	}
AdamGreen	0:616601bde9fb	417	}
AdamGreen	0:616601bde9fb	418
AdamGreen	0:616601bde9fb	419	/* At this point, the validation part begins: */
AdamGreen	0:616601bde9fb	420	/* If we already received the last fragment */
AdamGreen	0:616601bde9fb	421	if ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0) {
AdamGreen	0:616601bde9fb	422	/* and had no wholes so far */
AdamGreen	0:616601bde9fb	423	if (valid) {
AdamGreen	0:616601bde9fb	424	/* then check if the rest of the fragments is here */
AdamGreen	0:616601bde9fb	425	/* Check if the queue starts with the first datagram */
AdamGreen	0:616601bde9fb	426	if (((struct ip_reass_helper*)ipr->p->payload)->start != 0) {
AdamGreen	0:616601bde9fb	427	valid = 0;
AdamGreen	0:616601bde9fb	428	} else {
AdamGreen	0:616601bde9fb	429	/* and check that there are no wholes after this datagram */
AdamGreen	0:616601bde9fb	430	iprh_prev = iprh;
AdamGreen	0:616601bde9fb	431	q = iprh->next_pbuf;
AdamGreen	0:616601bde9fb	432	while (q != NULL) {
AdamGreen	0:616601bde9fb	433	iprh = (struct ip_reass_helper*)q->payload;
AdamGreen	0:616601bde9fb	434	if (iprh_prev->end != iprh->start) {
AdamGreen	0:616601bde9fb	435	valid = 0;
AdamGreen	0:616601bde9fb	436	break;
AdamGreen	0:616601bde9fb	437	}
AdamGreen	0:616601bde9fb	438	iprh_prev = iprh;
AdamGreen	0:616601bde9fb	439	q = iprh->next_pbuf;
AdamGreen	0:616601bde9fb	440	}
AdamGreen	0:616601bde9fb	441	/* if still valid, all fragments are received
AdamGreen	0:616601bde9fb	442	* (because to the MF==0 already arrived */
AdamGreen	0:616601bde9fb	443	if (valid) {
AdamGreen	0:616601bde9fb	444	LWIP_ASSERT("sanity check", ipr->p != NULL);
AdamGreen	0:616601bde9fb	445	LWIP_ASSERT("sanity check",
AdamGreen	0:616601bde9fb	446	((struct ip_reass_helper*)ipr->p->payload) != iprh);
AdamGreen	0:616601bde9fb	447	LWIP_ASSERT("validate_datagram:next_pbuf!=NULL",
AdamGreen	0:616601bde9fb	448	iprh->next_pbuf == NULL);
AdamGreen	0:616601bde9fb	449	LWIP_ASSERT("validate_datagram:datagram end!=datagram len",
AdamGreen	0:616601bde9fb	450	iprh->end == ipr->datagram_len);
AdamGreen	0:616601bde9fb	451	}
AdamGreen	0:616601bde9fb	452	}
AdamGreen	0:616601bde9fb	453	}
AdamGreen	0:616601bde9fb	454	/* If valid is 0 here, there are some fragments missing in the middle
AdamGreen	0:616601bde9fb	455	* (since MF == 0 has already arrived). Such datagrams simply time out if
AdamGreen	0:616601bde9fb	456	* no more fragments are received... */
AdamGreen	0:616601bde9fb	457	return valid;
AdamGreen	0:616601bde9fb	458	}
AdamGreen	0:616601bde9fb	459	/* If we come here, not all fragments were received, yet! */
AdamGreen	0:616601bde9fb	460	return 0; /* not yet valid! */
AdamGreen	0:616601bde9fb	461	#if IP_REASS_CHECK_OVERLAP
AdamGreen	0:616601bde9fb	462	freepbuf:
AdamGreen	0:616601bde9fb	463	ip_reass_pbufcount -= pbuf_clen(new_p);
AdamGreen	0:616601bde9fb	464	pbuf_free(new_p);
AdamGreen	0:616601bde9fb	465	return 0;
AdamGreen	0:616601bde9fb	466	#endif /* IP_REASS_CHECK_OVERLAP */
AdamGreen	0:616601bde9fb	467	}
AdamGreen	0:616601bde9fb	468
AdamGreen	0:616601bde9fb	469	/**
AdamGreen	0:616601bde9fb	470	* Reassembles incoming IP fragments into an IP datagram.
AdamGreen	0:616601bde9fb	471	*
AdamGreen	0:616601bde9fb	472	* @param p points to a pbuf chain of the fragment
AdamGreen	0:616601bde9fb	473	* @return NULL if reassembly is incomplete, ? otherwise
AdamGreen	0:616601bde9fb	474	*/
AdamGreen	0:616601bde9fb	475	struct pbuf *
AdamGreen	0:616601bde9fb	476	ip_reass(struct pbuf *p)
AdamGreen	0:616601bde9fb	477	{
AdamGreen	0:616601bde9fb	478	struct pbuf *r;
AdamGreen	0:616601bde9fb	479	struct ip_hdr *fraghdr;
AdamGreen	0:616601bde9fb	480	struct ip_reassdata *ipr;
AdamGreen	0:616601bde9fb	481	struct ip_reass_helper *iprh;
AdamGreen	0:616601bde9fb	482	u16_t offset, len;
AdamGreen	0:616601bde9fb	483	u8_t clen;
AdamGreen	0:616601bde9fb	484	struct ip_reassdata *ipr_prev = NULL;
AdamGreen	0:616601bde9fb	485
AdamGreen	0:616601bde9fb	486	IPFRAG_STATS_INC(ip_frag.recv);
AdamGreen	0:616601bde9fb	487	snmp_inc_ipreasmreqds();
AdamGreen	0:616601bde9fb	488
AdamGreen	0:616601bde9fb	489	fraghdr = (struct ip_hdr*)p->payload;
AdamGreen	0:616601bde9fb	490
AdamGreen	0:616601bde9fb	491	if ((IPH_HL(fraghdr) * 4) != IP_HLEN) {
AdamGreen	0:616601bde9fb	492	LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n"));
AdamGreen	0:616601bde9fb	493	IPFRAG_STATS_INC(ip_frag.err);
AdamGreen	0:616601bde9fb	494	goto nullreturn;
AdamGreen	0:616601bde9fb	495	}
AdamGreen	0:616601bde9fb	496
AdamGreen	0:616601bde9fb	497	offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
AdamGreen	0:616601bde9fb	498	len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
AdamGreen	0:616601bde9fb	499
AdamGreen	0:616601bde9fb	500	/* Check if we are allowed to enqueue more datagrams. */
AdamGreen	0:616601bde9fb	501	clen = pbuf_clen(p);
AdamGreen	0:616601bde9fb	502	if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
AdamGreen	0:616601bde9fb	503	#if IP_REASS_FREE_OLDEST
AdamGreen	0:616601bde9fb	504	if (!ip_reass_remove_oldest_datagram(fraghdr, clen) \|\|
AdamGreen	0:616601bde9fb	505	((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
AdamGreen	0:616601bde9fb	506	#endif /* IP_REASS_FREE_OLDEST */
AdamGreen	0:616601bde9fb	507	{
AdamGreen	0:616601bde9fb	508	/* No datagram could be freed and still too many pbufs enqueued */
AdamGreen	0:616601bde9fb	509	LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
AdamGreen	0:616601bde9fb	510	ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
AdamGreen	0:616601bde9fb	511	IPFRAG_STATS_INC(ip_frag.memerr);
AdamGreen	0:616601bde9fb	512	/* @todo: send ICMP time exceeded here? */
AdamGreen	0:616601bde9fb	513	/* drop this pbuf */
AdamGreen	0:616601bde9fb	514	goto nullreturn;
AdamGreen	0:616601bde9fb	515	}
AdamGreen	0:616601bde9fb	516	}
AdamGreen	0:616601bde9fb	517
AdamGreen	0:616601bde9fb	518	/* Look for the datagram the fragment belongs to in the current datagram queue,
AdamGreen	0:616601bde9fb	519	* remembering the previous in the queue for later dequeueing. */
AdamGreen	0:616601bde9fb	520	for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
AdamGreen	0:616601bde9fb	521	/* Check if the incoming fragment matches the one currently present
AdamGreen	0:616601bde9fb	522	in the reassembly buffer. If so, we proceed with copying the
AdamGreen	0:616601bde9fb	523	fragment into the buffer. */
AdamGreen	0:616601bde9fb	524	if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
AdamGreen	0:616601bde9fb	525	LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
AdamGreen	0:616601bde9fb	526	ntohs(IPH_ID(fraghdr))));
AdamGreen	0:616601bde9fb	527	IPFRAG_STATS_INC(ip_frag.cachehit);
AdamGreen	0:616601bde9fb	528	break;
AdamGreen	0:616601bde9fb	529	}
AdamGreen	0:616601bde9fb	530	ipr_prev = ipr;
AdamGreen	0:616601bde9fb	531	}
AdamGreen	0:616601bde9fb	532
AdamGreen	0:616601bde9fb	533	if (ipr == NULL) {
AdamGreen	0:616601bde9fb	534	/* Enqueue a new datagram into the datagram queue */
AdamGreen	0:616601bde9fb	535	ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
AdamGreen	0:616601bde9fb	536	/* Bail if unable to enqueue */
AdamGreen	0:616601bde9fb	537	if(ipr == NULL) {
AdamGreen	0:616601bde9fb	538	goto nullreturn;
AdamGreen	0:616601bde9fb	539	}
AdamGreen	0:616601bde9fb	540	} else {
AdamGreen	0:616601bde9fb	541	if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) &&
AdamGreen	0:616601bde9fb	542	((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
AdamGreen	0:616601bde9fb	543	/* ipr->iphdr is not the header from the first fragment, but fraghdr is
AdamGreen	0:616601bde9fb	544	* -> copy fraghdr into ipr->iphdr since we want to have the header
AdamGreen	0:616601bde9fb	545	* of the first fragment (for ICMP time exceeded and later, for copying
AdamGreen	0:616601bde9fb	546	* all options, if supported)*/
AdamGreen	0:616601bde9fb	547	SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
AdamGreen	0:616601bde9fb	548	}
AdamGreen	0:616601bde9fb	549	}
AdamGreen	0:616601bde9fb	550	/* Track the current number of pbufs current 'in-flight', in order to limit
AdamGreen	0:616601bde9fb	551	the number of fragments that may be enqueued at any one time */
AdamGreen	0:616601bde9fb	552	ip_reass_pbufcount += clen;
AdamGreen	0:616601bde9fb	553
AdamGreen	0:616601bde9fb	554	/* At this point, we have either created a new entry or pointing
AdamGreen	0:616601bde9fb	555	* to an existing one */
AdamGreen	0:616601bde9fb	556
AdamGreen	0:616601bde9fb	557	/* check for 'no more fragments', and update queue entry*/
AdamGreen	0:616601bde9fb	558	if ((IPH_OFFSET(fraghdr) & PP_NTOHS(IP_MF)) == 0) {
AdamGreen	0:616601bde9fb	559	ipr->flags \|= IP_REASS_FLAG_LASTFRAG;
AdamGreen	0:616601bde9fb	560	ipr->datagram_len = offset + len;
AdamGreen	0:616601bde9fb	561	LWIP_DEBUGF(IP_REASS_DEBUG,
AdamGreen	0:616601bde9fb	562	("ip_reass: last fragment seen, total len %"S16_F"\n",
AdamGreen	0:616601bde9fb	563	ipr->datagram_len));
AdamGreen	0:616601bde9fb	564	}
AdamGreen	0:616601bde9fb	565	/* find the right place to insert this pbuf */
AdamGreen	0:616601bde9fb	566	/* @todo: trim pbufs if fragments are overlapping */
AdamGreen	0:616601bde9fb	567	if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) {
AdamGreen	0:616601bde9fb	568	/* the totally last fragment (flag more fragments = 0) was received at least
AdamGreen	0:616601bde9fb	569	* once AND all fragments are received */
AdamGreen	0:616601bde9fb	570	ipr->datagram_len += IP_HLEN;
AdamGreen	0:616601bde9fb	571
AdamGreen	0:616601bde9fb	572	/* save the second pbuf before copying the header over the pointer */
AdamGreen	0:616601bde9fb	573	r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf;
AdamGreen	0:616601bde9fb	574
AdamGreen	0:616601bde9fb	575	/* copy the original ip header back to the first pbuf */
AdamGreen	0:616601bde9fb	576	fraghdr = (struct ip_hdr*)(ipr->p->payload);
AdamGreen	0:616601bde9fb	577	SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
AdamGreen	0:616601bde9fb	578	IPH_LEN_SET(fraghdr, htons(ipr->datagram_len));
AdamGreen	0:616601bde9fb	579	IPH_OFFSET_SET(fraghdr, 0);
AdamGreen	0:616601bde9fb	580	IPH_CHKSUM_SET(fraghdr, 0);
AdamGreen	0:616601bde9fb	581	/* @todo: do we need to set calculate the correct checksum? */
AdamGreen	0:616601bde9fb	582	IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));
AdamGreen	0:616601bde9fb	583
AdamGreen	0:616601bde9fb	584	p = ipr->p;
AdamGreen	0:616601bde9fb	585
AdamGreen	0:616601bde9fb	586	/* chain together the pbufs contained within the reass_data list. */
AdamGreen	0:616601bde9fb	587	while(r != NULL) {
AdamGreen	0:616601bde9fb	588	iprh = (struct ip_reass_helper*)r->payload;
AdamGreen	0:616601bde9fb	589
AdamGreen	0:616601bde9fb	590	/* hide the ip header for every succeding fragment */
AdamGreen	0:616601bde9fb	591	pbuf_header(r, -IP_HLEN);
AdamGreen	0:616601bde9fb	592	pbuf_cat(p, r);
AdamGreen	0:616601bde9fb	593	r = iprh->next_pbuf;
AdamGreen	0:616601bde9fb	594	}
AdamGreen	0:616601bde9fb	595	/* release the sources allocate for the fragment queue entry */
AdamGreen	0:616601bde9fb	596	ip_reass_dequeue_datagram(ipr, ipr_prev);
AdamGreen	0:616601bde9fb	597
AdamGreen	0:616601bde9fb	598	/* and adjust the number of pbufs currently queued for reassembly. */
AdamGreen	0:616601bde9fb	599	ip_reass_pbufcount -= pbuf_clen(p);
AdamGreen	0:616601bde9fb	600
AdamGreen	0:616601bde9fb	601	/* Return the pbuf chain */
AdamGreen	0:616601bde9fb	602	return p;
AdamGreen	0:616601bde9fb	603	}
AdamGreen	0:616601bde9fb	604	/* the datagram is not (yet?) reassembled completely */
AdamGreen	0:616601bde9fb	605	LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
AdamGreen	0:616601bde9fb	606	return NULL;
AdamGreen	0:616601bde9fb	607
AdamGreen	0:616601bde9fb	608	nullreturn:
AdamGreen	0:616601bde9fb	609	LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n"));
AdamGreen	0:616601bde9fb	610	IPFRAG_STATS_INC(ip_frag.drop);
AdamGreen	0:616601bde9fb	611	pbuf_free(p);
AdamGreen	0:616601bde9fb	612	return NULL;
AdamGreen	0:616601bde9fb	613	}
AdamGreen	0:616601bde9fb	614	#endif /* IP_REASSEMBLY */
AdamGreen	0:616601bde9fb	615
AdamGreen	0:616601bde9fb	616	#if IP_FRAG
AdamGreen	0:616601bde9fb	617	#if IP_FRAG_USES_STATIC_BUF
AdamGreen	0:616601bde9fb	618	static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU + MEM_ALIGNMENT - 1)];
AdamGreen	0:616601bde9fb	619	#else /* IP_FRAG_USES_STATIC_BUF */
AdamGreen	0:616601bde9fb	620
AdamGreen	0:616601bde9fb	621	#if !LWIP_NETIF_TX_SINGLE_PBUF
AdamGreen	0:616601bde9fb	622	/** Allocate a new struct pbuf_custom_ref */
AdamGreen	0:616601bde9fb	623	static struct pbuf_custom_ref*
AdamGreen	0:616601bde9fb	624	ip_frag_alloc_pbuf_custom_ref(void)
AdamGreen	0:616601bde9fb	625	{
AdamGreen	0:616601bde9fb	626	return (struct pbuf_custom_ref*)memp_malloc(MEMP_FRAG_PBUF);
AdamGreen	0:616601bde9fb	627	}
AdamGreen	0:616601bde9fb	628
AdamGreen	0:616601bde9fb	629	/** Free a struct pbuf_custom_ref */
AdamGreen	0:616601bde9fb	630	static void
AdamGreen	0:616601bde9fb	631	ip_frag_free_pbuf_custom_ref(struct pbuf_custom_ref* p)
AdamGreen	0:616601bde9fb	632	{
AdamGreen	0:616601bde9fb	633	LWIP_ASSERT("p != NULL", p != NULL);
AdamGreen	0:616601bde9fb	634	memp_free(MEMP_FRAG_PBUF, p);
AdamGreen	0:616601bde9fb	635	}
AdamGreen	0:616601bde9fb	636
AdamGreen	0:616601bde9fb	637	/** Free-callback function to free a 'struct pbuf_custom_ref', called by
AdamGreen	0:616601bde9fb	638	* pbuf_free. */
AdamGreen	0:616601bde9fb	639	static void
AdamGreen	0:616601bde9fb	640	ipfrag_free_pbuf_custom(struct pbuf *p)
AdamGreen	0:616601bde9fb	641	{
AdamGreen	0:616601bde9fb	642	struct pbuf_custom_ref pcr = (struct pbuf_custom_ref)p;
AdamGreen	0:616601bde9fb	643	LWIP_ASSERT("pcr != NULL", pcr != NULL);
AdamGreen	0:616601bde9fb	644	LWIP_ASSERT("pcr == p", (void)pcr == (void)p);
AdamGreen	0:616601bde9fb	645	if (pcr->original != NULL) {
AdamGreen	0:616601bde9fb	646	pbuf_free(pcr->original);
AdamGreen	0:616601bde9fb	647	}
AdamGreen	0:616601bde9fb	648	ip_frag_free_pbuf_custom_ref(pcr);
AdamGreen	0:616601bde9fb	649	}
AdamGreen	0:616601bde9fb	650	#endif /* !LWIP_NETIF_TX_SINGLE_PBUF */
AdamGreen	0:616601bde9fb	651	#endif /* IP_FRAG_USES_STATIC_BUF */
AdamGreen	0:616601bde9fb	652
AdamGreen	0:616601bde9fb	653	/**
AdamGreen	0:616601bde9fb	654	* Fragment an IP datagram if too large for the netif.
AdamGreen	0:616601bde9fb	655	*
AdamGreen	0:616601bde9fb	656	* Chop the datagram in MTU sized chunks and send them in order
AdamGreen	0:616601bde9fb	657	* by using a fixed size static memory buffer (PBUF_REF) or
AdamGreen	0:616601bde9fb	658	* point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF).
AdamGreen	0:616601bde9fb	659	*
AdamGreen	0:616601bde9fb	660	* @param p ip packet to send
AdamGreen	0:616601bde9fb	661	* @param netif the netif on which to send
AdamGreen	0:616601bde9fb	662	* @param dest destination ip address to which to send
AdamGreen	0:616601bde9fb	663	*
AdamGreen	0:616601bde9fb	664	* @return ERR_OK if sent successfully, err_t otherwise
AdamGreen	0:616601bde9fb	665	*/
AdamGreen	0:616601bde9fb	666	err_t
AdamGreen	0:616601bde9fb	667	ip_frag(struct pbuf p, struct netif netif, ip_addr_t *dest)
AdamGreen	0:616601bde9fb	668	{
AdamGreen	0:616601bde9fb	669	struct pbuf *rambuf;
AdamGreen	0:616601bde9fb	670	#if IP_FRAG_USES_STATIC_BUF
AdamGreen	0:616601bde9fb	671	struct pbuf *header;
AdamGreen	0:616601bde9fb	672	#else
AdamGreen	0:616601bde9fb	673	#if !LWIP_NETIF_TX_SINGLE_PBUF
AdamGreen	0:616601bde9fb	674	struct pbuf *newpbuf;
AdamGreen	0:616601bde9fb	675	#endif
AdamGreen	0:616601bde9fb	676	struct ip_hdr *original_iphdr;
AdamGreen	0:616601bde9fb	677	#endif
AdamGreen	0:616601bde9fb	678	struct ip_hdr *iphdr;
AdamGreen	0:616601bde9fb	679	u16_t nfb;
AdamGreen	0:616601bde9fb	680	u16_t left, cop;
AdamGreen	0:616601bde9fb	681	u16_t mtu = netif->mtu;
AdamGreen	0:616601bde9fb	682	u16_t ofo, omf;
AdamGreen	0:616601bde9fb	683	u16_t last;
AdamGreen	0:616601bde9fb	684	u16_t poff = IP_HLEN;
AdamGreen	0:616601bde9fb	685	u16_t tmp;
AdamGreen	0:616601bde9fb	686	#if !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF
AdamGreen	0:616601bde9fb	687	u16_t newpbuflen = 0;
AdamGreen	0:616601bde9fb	688	u16_t left_to_copy;
AdamGreen	0:616601bde9fb	689	#endif
AdamGreen	0:616601bde9fb	690
AdamGreen	0:616601bde9fb	691	/* Get a RAM based MTU sized pbuf */
AdamGreen	0:616601bde9fb	692	#if IP_FRAG_USES_STATIC_BUF
AdamGreen	0:616601bde9fb	693	/* When using a static buffer, we use a PBUF_REF, which we will
AdamGreen	0:616601bde9fb	694	* use to reference the packet (without link header).
AdamGreen	0:616601bde9fb	695	* Layer and length is irrelevant.
AdamGreen	0:616601bde9fb	696	*/
AdamGreen	0:616601bde9fb	697	rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
AdamGreen	0:616601bde9fb	698	if (rambuf == NULL) {
AdamGreen	0:616601bde9fb	699	LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n"));
AdamGreen	0:616601bde9fb	700	return ERR_MEM;
AdamGreen	0:616601bde9fb	701	}
AdamGreen	0:616601bde9fb	702	rambuf->tot_len = rambuf->len = mtu;
AdamGreen	0:616601bde9fb	703	rambuf->payload = LWIP_MEM_ALIGN((void *)buf);
AdamGreen	0:616601bde9fb	704
AdamGreen	0:616601bde9fb	705	/* Copy the IP header in it */
AdamGreen	0:616601bde9fb	706	iphdr = (struct ip_hdr *)rambuf->payload;
AdamGreen	0:616601bde9fb	707	SMEMCPY(iphdr, p->payload, IP_HLEN);
AdamGreen	0:616601bde9fb	708	#else /* IP_FRAG_USES_STATIC_BUF */
AdamGreen	0:616601bde9fb	709	original_iphdr = (struct ip_hdr *)p->payload;
AdamGreen	0:616601bde9fb	710	iphdr = original_iphdr;
AdamGreen	0:616601bde9fb	711	#endif /* IP_FRAG_USES_STATIC_BUF */
AdamGreen	0:616601bde9fb	712
AdamGreen	0:616601bde9fb	713	/* Save original offset */
AdamGreen	0:616601bde9fb	714	tmp = ntohs(IPH_OFFSET(iphdr));
AdamGreen	0:616601bde9fb	715	ofo = tmp & IP_OFFMASK;
AdamGreen	0:616601bde9fb	716	omf = tmp & IP_MF;
AdamGreen	0:616601bde9fb	717
AdamGreen	0:616601bde9fb	718	left = p->tot_len - IP_HLEN;
AdamGreen	0:616601bde9fb	719
AdamGreen	0:616601bde9fb	720	nfb = (mtu - IP_HLEN) / 8;
AdamGreen	0:616601bde9fb	721
AdamGreen	0:616601bde9fb	722	while (left) {
AdamGreen	0:616601bde9fb	723	last = (left <= mtu - IP_HLEN);
AdamGreen	0:616601bde9fb	724
AdamGreen	0:616601bde9fb	725	/* Set new offset and MF flag */
AdamGreen	0:616601bde9fb	726	tmp = omf \| (IP_OFFMASK & (ofo));
AdamGreen	0:616601bde9fb	727	if (!last) {
AdamGreen	0:616601bde9fb	728	tmp = tmp \| IP_MF;
AdamGreen	0:616601bde9fb	729	}
AdamGreen	0:616601bde9fb	730
AdamGreen	0:616601bde9fb	731	/* Fill this fragment */
AdamGreen	0:616601bde9fb	732	cop = last ? left : nfb * 8;
AdamGreen	0:616601bde9fb	733
AdamGreen	0:616601bde9fb	734	#if IP_FRAG_USES_STATIC_BUF
AdamGreen	0:616601bde9fb	735	poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
AdamGreen	0:616601bde9fb	736	#else /* IP_FRAG_USES_STATIC_BUF */
AdamGreen	0:616601bde9fb	737	#if LWIP_NETIF_TX_SINGLE_PBUF
AdamGreen	0:616601bde9fb	738	rambuf = pbuf_alloc(PBUF_IP, cop, PBUF_RAM);
AdamGreen	0:616601bde9fb	739	if (rambuf == NULL) {
AdamGreen	0:616601bde9fb	740	return ERR_MEM;
AdamGreen	0:616601bde9fb	741	}
AdamGreen	0:616601bde9fb	742	LWIP_ASSERT("this needs a pbuf in one piece!",
AdamGreen	0:616601bde9fb	743	(rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
AdamGreen	0:616601bde9fb	744	poff += pbuf_copy_partial(p, rambuf->payload, cop, poff);
AdamGreen	0:616601bde9fb	745	/* make room for the IP header */
AdamGreen	0:616601bde9fb	746	if(pbuf_header(rambuf, IP_HLEN)) {
AdamGreen	0:616601bde9fb	747	pbuf_free(rambuf);
AdamGreen	0:616601bde9fb	748	return ERR_MEM;
AdamGreen	0:616601bde9fb	749	}
AdamGreen	0:616601bde9fb	750	/* fill in the IP header */
AdamGreen	0:616601bde9fb	751	SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
AdamGreen	0:616601bde9fb	752	iphdr = rambuf->payload;
AdamGreen	0:616601bde9fb	753	#else /* LWIP_NETIF_TX_SINGLE_PBUF */
AdamGreen	0:616601bde9fb	754	/* When not using a static buffer, create a chain of pbufs.
AdamGreen	0:616601bde9fb	755	* The first will be a PBUF_RAM holding the link and IP header.
AdamGreen	0:616601bde9fb	756	* The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
AdamGreen	0:616601bde9fb	757	* but limited to the size of an mtu.
AdamGreen	0:616601bde9fb	758	*/
AdamGreen	0:616601bde9fb	759	rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
AdamGreen	0:616601bde9fb	760	if (rambuf == NULL) {
AdamGreen	0:616601bde9fb	761	return ERR_MEM;
AdamGreen	0:616601bde9fb	762	}
AdamGreen	0:616601bde9fb	763	LWIP_ASSERT("this needs a pbuf in one piece!",
AdamGreen	0:616601bde9fb	764	(p->len >= (IP_HLEN)));
AdamGreen	0:616601bde9fb	765	SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
AdamGreen	0:616601bde9fb	766	iphdr = (struct ip_hdr *)rambuf->payload;
AdamGreen	0:616601bde9fb	767
AdamGreen	0:616601bde9fb	768	/* Can just adjust p directly for needed offset. */
AdamGreen	0:616601bde9fb	769	p->payload = (u8_t *)p->payload + poff;
AdamGreen	0:616601bde9fb	770	p->len -= poff;
AdamGreen	0:616601bde9fb	771
AdamGreen	0:616601bde9fb	772	left_to_copy = cop;
AdamGreen	0:616601bde9fb	773	while (left_to_copy) {
AdamGreen	0:616601bde9fb	774	struct pbuf_custom_ref *pcr;
AdamGreen	0:616601bde9fb	775	newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
AdamGreen	0:616601bde9fb	776	/* Is this pbuf already empty? */
AdamGreen	0:616601bde9fb	777	if (!newpbuflen) {
AdamGreen	0:616601bde9fb	778	p = p->next;
AdamGreen	0:616601bde9fb	779	continue;
AdamGreen	0:616601bde9fb	780	}
AdamGreen	0:616601bde9fb	781	pcr = ip_frag_alloc_pbuf_custom_ref();
AdamGreen	0:616601bde9fb	782	if (pcr == NULL) {
AdamGreen	0:616601bde9fb	783	pbuf_free(rambuf);
AdamGreen	0:616601bde9fb	784	return ERR_MEM;
AdamGreen	0:616601bde9fb	785	}
AdamGreen	0:616601bde9fb	786	/* Mirror this pbuf, although we might not need all of it. */
AdamGreen	0:616601bde9fb	787	newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
AdamGreen	0:616601bde9fb	788	if (newpbuf == NULL) {
AdamGreen	0:616601bde9fb	789	ip_frag_free_pbuf_custom_ref(pcr);
AdamGreen	0:616601bde9fb	790	pbuf_free(rambuf);
AdamGreen	0:616601bde9fb	791	return ERR_MEM;
AdamGreen	0:616601bde9fb	792	}
AdamGreen	0:616601bde9fb	793	pbuf_ref(p);
AdamGreen	0:616601bde9fb	794	pcr->original = p;
AdamGreen	0:616601bde9fb	795	pcr->pc.custom_free_function = ipfrag_free_pbuf_custom;
AdamGreen	0:616601bde9fb	796
AdamGreen	0:616601bde9fb	797	/* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
AdamGreen	0:616601bde9fb	798	* so that it is removed when pbuf_dechain is later called on rambuf.
AdamGreen	0:616601bde9fb	799	*/
AdamGreen	0:616601bde9fb	800	pbuf_cat(rambuf, newpbuf);
AdamGreen	0:616601bde9fb	801	left_to_copy -= newpbuflen;
AdamGreen	0:616601bde9fb	802	if (left_to_copy) {
AdamGreen	0:616601bde9fb	803	p = p->next;
AdamGreen	0:616601bde9fb	804	}
AdamGreen	0:616601bde9fb	805	}
AdamGreen	0:616601bde9fb	806	poff = newpbuflen;
AdamGreen	0:616601bde9fb	807	#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
AdamGreen	0:616601bde9fb	808	#endif /* IP_FRAG_USES_STATIC_BUF */
AdamGreen	0:616601bde9fb	809
AdamGreen	0:616601bde9fb	810	/* Correct header */
AdamGreen	0:616601bde9fb	811	IPH_OFFSET_SET(iphdr, htons(tmp));
AdamGreen	0:616601bde9fb	812	IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
AdamGreen	0:616601bde9fb	813	IPH_CHKSUM_SET(iphdr, 0);
AdamGreen	0:616601bde9fb	814	IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
AdamGreen	0:616601bde9fb	815
AdamGreen	0:616601bde9fb	816	#if IP_FRAG_USES_STATIC_BUF
AdamGreen	0:616601bde9fb	817	if (last) {
AdamGreen	0:616601bde9fb	818	pbuf_realloc(rambuf, left + IP_HLEN);
AdamGreen	0:616601bde9fb	819	}
AdamGreen	0:616601bde9fb	820
AdamGreen	0:616601bde9fb	821	/* This part is ugly: we alloc a RAM based pbuf for
AdamGreen	0:616601bde9fb	822	* the link level header for each chunk and then
AdamGreen	0:616601bde9fb	823	* free it.A PBUF_ROM style pbuf for which pbuf_header
AdamGreen	0:616601bde9fb	824	* worked would make things simpler.
AdamGreen	0:616601bde9fb	825	*/
AdamGreen	0:616601bde9fb	826	header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
AdamGreen	0:616601bde9fb	827	if (header != NULL) {
AdamGreen	0:616601bde9fb	828	pbuf_chain(header, rambuf);
AdamGreen	0:616601bde9fb	829	netif->output(netif, header, dest);
AdamGreen	0:616601bde9fb	830	IPFRAG_STATS_INC(ip_frag.xmit);
AdamGreen	0:616601bde9fb	831	snmp_inc_ipfragcreates();
AdamGreen	0:616601bde9fb	832	pbuf_free(header);
AdamGreen	0:616601bde9fb	833	} else {
AdamGreen	0:616601bde9fb	834	LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
AdamGreen	0:616601bde9fb	835	pbuf_free(rambuf);
AdamGreen	0:616601bde9fb	836	return ERR_MEM;
AdamGreen	0:616601bde9fb	837	}
AdamGreen	0:616601bde9fb	838	#else /* IP_FRAG_USES_STATIC_BUF */
AdamGreen	0:616601bde9fb	839	/* No need for separate header pbuf - we allowed room for it in rambuf
AdamGreen	0:616601bde9fb	840	* when allocated.
AdamGreen	0:616601bde9fb	841	*/
AdamGreen	0:616601bde9fb	842	netif->output(netif, rambuf, dest);
AdamGreen	0:616601bde9fb	843	IPFRAG_STATS_INC(ip_frag.xmit);
AdamGreen	0:616601bde9fb	844
AdamGreen	0:616601bde9fb	845	/* Unfortunately we can't reuse rambuf - the hardware may still be
AdamGreen	0:616601bde9fb	846	* using the buffer. Instead we free it (and the ensuing chain) and
AdamGreen	0:616601bde9fb	847	* recreate it next time round the loop. If we're lucky the hardware
AdamGreen	0:616601bde9fb	848	* will have already sent the packet, the free will really free, and
AdamGreen	0:616601bde9fb	849	* there will be zero memory penalty.
AdamGreen	0:616601bde9fb	850	*/
AdamGreen	0:616601bde9fb	851
AdamGreen	0:616601bde9fb	852	pbuf_free(rambuf);
AdamGreen	0:616601bde9fb	853	#endif /* IP_FRAG_USES_STATIC_BUF */
AdamGreen	0:616601bde9fb	854	left -= cop;
AdamGreen	0:616601bde9fb	855	ofo += nfb;
AdamGreen	0:616601bde9fb	856	}
AdamGreen	0:616601bde9fb	857	#if IP_FRAG_USES_STATIC_BUF
AdamGreen	0:616601bde9fb	858	pbuf_free(rambuf);
AdamGreen	0:616601bde9fb	859	#endif /* IP_FRAG_USES_STATIC_BUF */
AdamGreen	0:616601bde9fb	860	snmp_inc_ipfragoks();
AdamGreen	0:616601bde9fb	861	return ERR_OK;
AdamGreen	0:616601bde9fb	862	}
AdamGreen	0:616601bde9fb	863	#endif /* IP_FRAG */

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	23 Feb 2012
Imports:	113
Forks:	0
Commits:	2
Dependents:	0
Dependencies:	4
Followers:	6

NetStack/lwip/core/ipv4/ip_frag.c@0:616601bde9fb, 2012-02-23 (annotated)

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