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Jesper Taxbøl / Mbed 2 deprecated TCPSpeedTest

I have a problem getting this to work. Server only recieves half of the data being sent. Whats wrong

lwip/core/ipv4/ip_frag.c@0:66300c77c6e9, 2011-03-29 (annotated)

Committer:: tax
Date:: Tue Mar 29 13:20:15 2011 +0000
Revision:: 0:66300c77c6e9

Who changed what in which revision?

User	Revision	Line number	New contents of line
tax	0:66300c77c6e9	1	/**
tax	0:66300c77c6e9	2	* @file
tax	0:66300c77c6e9	3	* This is the IPv4 packet segmentation and reassembly implementation.
tax	0:66300c77c6e9	4	*
tax	0:66300c77c6e9	5	*/
tax	0:66300c77c6e9	6
tax	0:66300c77c6e9	7	/*
tax	0:66300c77c6e9	8	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
tax	0:66300c77c6e9	9	* All rights reserved.
tax	0:66300c77c6e9	10	*
tax	0:66300c77c6e9	11	* Redistribution and use in source and binary forms, with or without modification,
tax	0:66300c77c6e9	12	* are permitted provided that the following conditions are met:
tax	0:66300c77c6e9	13	*
tax	0:66300c77c6e9	14	* 1. Redistributions of source code must retain the above copyright notice,
tax	0:66300c77c6e9	15	* this list of conditions and the following disclaimer.
tax	0:66300c77c6e9	16	* 2. Redistributions in binary form must reproduce the above copyright notice,
tax	0:66300c77c6e9	17	* this list of conditions and the following disclaimer in the documentation
tax	0:66300c77c6e9	18	* and/or other materials provided with the distribution.
tax	0:66300c77c6e9	19	* 3. The name of the author may not be used to endorse or promote products
tax	0:66300c77c6e9	20	* derived from this software without specific prior written permission.
tax	0:66300c77c6e9	21	*
tax	0:66300c77c6e9	22	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
tax	0:66300c77c6e9	23	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
tax	0:66300c77c6e9	24	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
tax	0:66300c77c6e9	25	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
tax	0:66300c77c6e9	26	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
tax	0:66300c77c6e9	27	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
tax	0:66300c77c6e9	28	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
tax	0:66300c77c6e9	29	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
tax	0:66300c77c6e9	30	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
tax	0:66300c77c6e9	31	* OF SUCH DAMAGE.
tax	0:66300c77c6e9	32	*
tax	0:66300c77c6e9	33	* This file is part of the lwIP TCP/IP stack.
tax	0:66300c77c6e9	34	*
tax	0:66300c77c6e9	35	* Author: Jani Monoses <jani@iv.ro>
tax	0:66300c77c6e9	36	* Simon Goldschmidt
tax	0:66300c77c6e9	37	* original reassembly code by Adam Dunkels <adam@sics.se>
tax	0:66300c77c6e9	38	*
tax	0:66300c77c6e9	39	*/
tax	0:66300c77c6e9	40
tax	0:66300c77c6e9	41	#include "lwip/opt.h"
tax	0:66300c77c6e9	42	#include "lwip/ip_frag.h"
tax	0:66300c77c6e9	43	#include "lwip/def.h"
tax	0:66300c77c6e9	44	#include "lwip/inet_chksum.h"
tax	0:66300c77c6e9	45	#include "lwip/netif.h"
tax	0:66300c77c6e9	46	#include "lwip/snmp.h"
tax	0:66300c77c6e9	47	#include "lwip/stats.h"
tax	0:66300c77c6e9	48	#include "lwip/icmp.h"
tax	0:66300c77c6e9	49
tax	0:66300c77c6e9	50	#include <string.h>
tax	0:66300c77c6e9	51
tax	0:66300c77c6e9	52	#if IP_REASSEMBLY
tax	0:66300c77c6e9	53	/**
tax	0:66300c77c6e9	54	* The IP reassembly code currently has the following limitations:
tax	0:66300c77c6e9	55	* - IP header options are not supported
tax	0:66300c77c6e9	56	* - fragments must not overlap (e.g. due to different routes),
tax	0:66300c77c6e9	57	* currently, overlapping or duplicate fragments are thrown away
tax	0:66300c77c6e9	58	* if IP_REASS_CHECK_OVERLAP=1 (the default)!
tax	0:66300c77c6e9	59	*
tax	0:66300c77c6e9	60	* @todo: work with IP header options
tax	0:66300c77c6e9	61	*/
tax	0:66300c77c6e9	62
tax	0:66300c77c6e9	63	/** Setting this to 0, you can turn off checking the fragments for overlapping
tax	0:66300c77c6e9	64	* regions. The code gets a little smaller. Only use this if you know that
tax	0:66300c77c6e9	65	* overlapping won't occur on your network! */
tax	0:66300c77c6e9	66	#ifndef IP_REASS_CHECK_OVERLAP
tax	0:66300c77c6e9	67	#define IP_REASS_CHECK_OVERLAP 1
tax	0:66300c77c6e9	68	#endif /* IP_REASS_CHECK_OVERLAP */
tax	0:66300c77c6e9	69
tax	0:66300c77c6e9	70	/** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
tax	0:66300c77c6e9	71	* full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
tax	0:66300c77c6e9	72	* Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
tax	0:66300c77c6e9	73	* is set to 1, so one datagram can be reassembled at a time, only. */
tax	0:66300c77c6e9	74	#ifndef IP_REASS_FREE_OLDEST
tax	0:66300c77c6e9	75	#define IP_REASS_FREE_OLDEST 1
tax	0:66300c77c6e9	76	#endif /* IP_REASS_FREE_OLDEST */
tax	0:66300c77c6e9	77
tax	0:66300c77c6e9	78	#define IP_REASS_FLAG_LASTFRAG 0x01
tax	0:66300c77c6e9	79
tax	0:66300c77c6e9	80	/** This is a helper struct which holds the starting
tax	0:66300c77c6e9	81	* offset and the ending offset of this fragment to
tax	0:66300c77c6e9	82	* easily chain the fragments.
tax	0:66300c77c6e9	83	* It has the same packing requirements as the IP header, since it replaces
tax	0:66300c77c6e9	84	* the IP header in memory in incoming fragments (after copying it) to keep
tax	0:66300c77c6e9	85	* track of the various fragments. (-> If the IP header doesn't need packing,
tax	0:66300c77c6e9	86	* this struct doesn't need packing, too.)
tax	0:66300c77c6e9	87	*/
tax	0:66300c77c6e9	88	#ifdef PACK_STRUCT_USE_INCLUDES
tax	0:66300c77c6e9	89	# include "arch/bpstruct.h"
tax	0:66300c77c6e9	90	#endif
tax	0:66300c77c6e9	91	PACK_STRUCT_BEGIN
tax	0:66300c77c6e9	92	struct ip_reass_helper {
tax	0:66300c77c6e9	93	PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
tax	0:66300c77c6e9	94	PACK_STRUCT_FIELD(u16_t start);
tax	0:66300c77c6e9	95	PACK_STRUCT_FIELD(u16_t end);
tax	0:66300c77c6e9	96	} PACK_STRUCT_STRUCT;
tax	0:66300c77c6e9	97	PACK_STRUCT_END
tax	0:66300c77c6e9	98	#ifdef PACK_STRUCT_USE_INCLUDES
tax	0:66300c77c6e9	99	# include "arch/epstruct.h"
tax	0:66300c77c6e9	100	#endif
tax	0:66300c77c6e9	101
tax	0:66300c77c6e9	102	#define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB) \
tax	0:66300c77c6e9	103	(ip_addr_cmp(&(iphdrA)->src, &(iphdrB)->src) && \
tax	0:66300c77c6e9	104	ip_addr_cmp(&(iphdrA)->dest, &(iphdrB)->dest) && \
tax	0:66300c77c6e9	105	IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0
tax	0:66300c77c6e9	106
tax	0:66300c77c6e9	107	/* global variables */
tax	0:66300c77c6e9	108	static struct ip_reassdata *reassdatagrams;
tax	0:66300c77c6e9	109	static u16_t ip_reass_pbufcount;
tax	0:66300c77c6e9	110
tax	0:66300c77c6e9	111	/* function prototypes */
tax	0:66300c77c6e9	112	static void ip_reass_dequeue_datagram(struct ip_reassdata ipr, struct ip_reassdata prev);
tax	0:66300c77c6e9	113	static int ip_reass_free_complete_datagram(struct ip_reassdata ipr, struct ip_reassdata prev);
tax	0:66300c77c6e9	114
tax	0:66300c77c6e9	115	/**
tax	0:66300c77c6e9	116	* Reassembly timer base function
tax	0:66300c77c6e9	117	* for both NO_SYS == 0 and 1 (!).
tax	0:66300c77c6e9	118	*
tax	0:66300c77c6e9	119	* Should be called every 1000 msec (defined by IP_TMR_INTERVAL).
tax	0:66300c77c6e9	120	*/
tax	0:66300c77c6e9	121	void
tax	0:66300c77c6e9	122	ip_reass_tmr(void)
tax	0:66300c77c6e9	123	{
tax	0:66300c77c6e9	124	struct ip_reassdata r, prev = NULL;
tax	0:66300c77c6e9	125
tax	0:66300c77c6e9	126	r = reassdatagrams;
tax	0:66300c77c6e9	127	while (r != NULL) {
tax	0:66300c77c6e9	128	/* Decrement the timer. Once it reaches 0,
tax	0:66300c77c6e9	129	* clean up the incomplete fragment assembly */
tax	0:66300c77c6e9	130	if (r->timer > 0) {
tax	0:66300c77c6e9	131	r->timer--;
tax	0:66300c77c6e9	132	LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)r->timer));
tax	0:66300c77c6e9	133	prev = r;
tax	0:66300c77c6e9	134	r = r->next;
tax	0:66300c77c6e9	135	} else {
tax	0:66300c77c6e9	136	/* reassembly timed out */
tax	0:66300c77c6e9	137	struct ip_reassdata *tmp;
tax	0:66300c77c6e9	138	LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out\n"));
tax	0:66300c77c6e9	139	tmp = r;
tax	0:66300c77c6e9	140	/* get the next pointer before freeing */
tax	0:66300c77c6e9	141	r = r->next;
tax	0:66300c77c6e9	142	/* free the helper struct and all enqueued pbufs */
tax	0:66300c77c6e9	143	ip_reass_free_complete_datagram(tmp, prev);
tax	0:66300c77c6e9	144	}
tax	0:66300c77c6e9	145	}
tax	0:66300c77c6e9	146	}
tax	0:66300c77c6e9	147
tax	0:66300c77c6e9	148	/**
tax	0:66300c77c6e9	149	* Free a datagram (struct ip_reassdata) and all its pbufs.
tax	0:66300c77c6e9	150	* Updates the total count of enqueued pbufs (ip_reass_pbufcount),
tax	0:66300c77c6e9	151	* SNMP counters and sends an ICMP time exceeded packet.
tax	0:66300c77c6e9	152	*
tax	0:66300c77c6e9	153	* @param ipr datagram to free
tax	0:66300c77c6e9	154	* @param prev the previous datagram in the linked list
tax	0:66300c77c6e9	155	* @return the number of pbufs freed
tax	0:66300c77c6e9	156	*/
tax	0:66300c77c6e9	157	static int
tax	0:66300c77c6e9	158	ip_reass_free_complete_datagram(struct ip_reassdata ipr, struct ip_reassdata prev)
tax	0:66300c77c6e9	159	{
tax	0:66300c77c6e9	160	u16_t pbufs_freed = 0;
tax	0:66300c77c6e9	161	u8_t clen;
tax	0:66300c77c6e9	162	struct pbuf *p;
tax	0:66300c77c6e9	163	struct ip_reass_helper *iprh;
tax	0:66300c77c6e9	164
tax	0:66300c77c6e9	165	LWIP_ASSERT("prev != ipr", prev != ipr);
tax	0:66300c77c6e9	166	if (prev != NULL) {
tax	0:66300c77c6e9	167	LWIP_ASSERT("prev->next == ipr", prev->next == ipr);
tax	0:66300c77c6e9	168	}
tax	0:66300c77c6e9	169
tax	0:66300c77c6e9	170	snmp_inc_ipreasmfails();
tax	0:66300c77c6e9	171	#if LWIP_ICMP
tax	0:66300c77c6e9	172	iprh = (struct ip_reass_helper *)ipr->p->payload;
tax	0:66300c77c6e9	173	if (iprh->start == 0) {
tax	0:66300c77c6e9	174	/* The first fragment was received, send ICMP time exceeded. */
tax	0:66300c77c6e9	175	/* First, de-queue the first pbuf from r->p. */
tax	0:66300c77c6e9	176	p = ipr->p;
tax	0:66300c77c6e9	177	ipr->p = iprh->next_pbuf;
tax	0:66300c77c6e9	178	/* Then, copy the original header into it. */
tax	0:66300c77c6e9	179	SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN);
tax	0:66300c77c6e9	180	icmp_time_exceeded(p, ICMP_TE_FRAG);
tax	0:66300c77c6e9	181	clen = pbuf_clen(p);
tax	0:66300c77c6e9	182	LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
tax	0:66300c77c6e9	183	pbufs_freed += clen;
tax	0:66300c77c6e9	184	pbuf_free(p);
tax	0:66300c77c6e9	185	}
tax	0:66300c77c6e9	186	#endif /* LWIP_ICMP */
tax	0:66300c77c6e9	187
tax	0:66300c77c6e9	188	/* First, free all received pbufs. The individual pbufs need to be released
tax	0:66300c77c6e9	189	separately as they have not yet been chained */
tax	0:66300c77c6e9	190	p = ipr->p;
tax	0:66300c77c6e9	191	while (p != NULL) {
tax	0:66300c77c6e9	192	struct pbuf *pcur;
tax	0:66300c77c6e9	193	iprh = (struct ip_reass_helper *)p->payload;
tax	0:66300c77c6e9	194	pcur = p;
tax	0:66300c77c6e9	195	/* get the next pointer before freeing */
tax	0:66300c77c6e9	196	p = iprh->next_pbuf;
tax	0:66300c77c6e9	197	clen = pbuf_clen(pcur);
tax	0:66300c77c6e9	198	LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
tax	0:66300c77c6e9	199	pbufs_freed += clen;
tax	0:66300c77c6e9	200	pbuf_free(pcur);
tax	0:66300c77c6e9	201	}
tax	0:66300c77c6e9	202	/* Then, unchain the struct ip_reassdata from the list and free it. */
tax	0:66300c77c6e9	203	ip_reass_dequeue_datagram(ipr, prev);
tax	0:66300c77c6e9	204	LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= pbufs_freed);
tax	0:66300c77c6e9	205	ip_reass_pbufcount -= pbufs_freed;
tax	0:66300c77c6e9	206
tax	0:66300c77c6e9	207	return pbufs_freed;
tax	0:66300c77c6e9	208	}
tax	0:66300c77c6e9	209
tax	0:66300c77c6e9	210	#if IP_REASS_FREE_OLDEST
tax	0:66300c77c6e9	211	/**
tax	0:66300c77c6e9	212	* Free the oldest datagram to make room for enqueueing new fragments.
tax	0:66300c77c6e9	213	* The datagram 'fraghdr' belongs to is not freed!
tax	0:66300c77c6e9	214	*
tax	0:66300c77c6e9	215	* @param fraghdr IP header of the current fragment
tax	0:66300c77c6e9	216	* @param pbufs_needed number of pbufs needed to enqueue
tax	0:66300c77c6e9	217	* (used for freeing other datagrams if not enough space)
tax	0:66300c77c6e9	218	* @return the number of pbufs freed
tax	0:66300c77c6e9	219	*/
tax	0:66300c77c6e9	220	static int
tax	0:66300c77c6e9	221	ip_reass_remove_oldest_datagram(struct ip_hdr *fraghdr, int pbufs_needed)
tax	0:66300c77c6e9	222	{
tax	0:66300c77c6e9	223	/* @todo Can't we simply remove the last datagram in the
tax	0:66300c77c6e9	224	* linked list behind reassdatagrams?
tax	0:66300c77c6e9	225	*/
tax	0:66300c77c6e9	226	struct ip_reassdata r, oldest, *prev;
tax	0:66300c77c6e9	227	int pbufs_freed = 0, pbufs_freed_current;
tax	0:66300c77c6e9	228	int other_datagrams;
tax	0:66300c77c6e9	229
tax	0:66300c77c6e9	230	/* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
tax	0:66300c77c6e9	231	* but don't free the datagram that 'fraghdr' belongs to! */
tax	0:66300c77c6e9	232	do {
tax	0:66300c77c6e9	233	oldest = NULL;
tax	0:66300c77c6e9	234	prev = NULL;
tax	0:66300c77c6e9	235	other_datagrams = 0;
tax	0:66300c77c6e9	236	r = reassdatagrams;
tax	0:66300c77c6e9	237	while (r != NULL) {
tax	0:66300c77c6e9	238	if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) {
tax	0:66300c77c6e9	239	/* Not the same datagram as fraghdr */
tax	0:66300c77c6e9	240	other_datagrams++;
tax	0:66300c77c6e9	241	if (oldest == NULL) {
tax	0:66300c77c6e9	242	oldest = r;
tax	0:66300c77c6e9	243	} else if (r->timer <= oldest->timer) {
tax	0:66300c77c6e9	244	/* older than the previous oldest */
tax	0:66300c77c6e9	245	oldest = r;
tax	0:66300c77c6e9	246	}
tax	0:66300c77c6e9	247	}
tax	0:66300c77c6e9	248	if (r->next != NULL) {
tax	0:66300c77c6e9	249	prev = r;
tax	0:66300c77c6e9	250	}
tax	0:66300c77c6e9	251	r = r->next;
tax	0:66300c77c6e9	252	}
tax	0:66300c77c6e9	253	if (oldest != NULL) {
tax	0:66300c77c6e9	254	pbufs_freed_current = ip_reass_free_complete_datagram(oldest, prev);
tax	0:66300c77c6e9	255	pbufs_freed += pbufs_freed_current;
tax	0:66300c77c6e9	256	}
tax	0:66300c77c6e9	257	} while ((pbufs_freed < pbufs_needed) && (other_datagrams > 1));
tax	0:66300c77c6e9	258	return pbufs_freed;
tax	0:66300c77c6e9	259	}
tax	0:66300c77c6e9	260	#endif /* IP_REASS_FREE_OLDEST */
tax	0:66300c77c6e9	261
tax	0:66300c77c6e9	262	/**
tax	0:66300c77c6e9	263	* Enqueues a new fragment into the fragment queue
tax	0:66300c77c6e9	264	* @param fraghdr points to the new fragments IP hdr
tax	0:66300c77c6e9	265	* @param clen number of pbufs needed to enqueue (used for freeing other datagrams if not enough space)
tax	0:66300c77c6e9	266	* @return A pointer to the queue location into which the fragment was enqueued
tax	0:66300c77c6e9	267	*/
tax	0:66300c77c6e9	268	static struct ip_reassdata*
tax	0:66300c77c6e9	269	ip_reass_enqueue_new_datagram(struct ip_hdr *fraghdr, int clen)
tax	0:66300c77c6e9	270	{
tax	0:66300c77c6e9	271	struct ip_reassdata* ipr;
tax	0:66300c77c6e9	272	/* No matching previous fragment found, allocate a new reassdata struct */
tax	0:66300c77c6e9	273	ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
tax	0:66300c77c6e9	274	if (ipr == NULL) {
tax	0:66300c77c6e9	275	#if IP_REASS_FREE_OLDEST
tax	0:66300c77c6e9	276	if (ip_reass_remove_oldest_datagram(fraghdr, clen) >= clen) {
tax	0:66300c77c6e9	277	ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
tax	0:66300c77c6e9	278	}
tax	0:66300c77c6e9	279	if (ipr == NULL)
tax	0:66300c77c6e9	280	#endif /* IP_REASS_FREE_OLDEST */
tax	0:66300c77c6e9	281	{
tax	0:66300c77c6e9	282	IPFRAG_STATS_INC(ip_frag.memerr);
tax	0:66300c77c6e9	283	LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct\n"));
tax	0:66300c77c6e9	284	return NULL;
tax	0:66300c77c6e9	285	}
tax	0:66300c77c6e9	286	}
tax	0:66300c77c6e9	287	memset(ipr, 0, sizeof(struct ip_reassdata));
tax	0:66300c77c6e9	288	ipr->timer = IP_REASS_MAXAGE;
tax	0:66300c77c6e9	289
tax	0:66300c77c6e9	290	/* enqueue the new structure to the front of the list */
tax	0:66300c77c6e9	291	ipr->next = reassdatagrams;
tax	0:66300c77c6e9	292	reassdatagrams = ipr;
tax	0:66300c77c6e9	293	/* copy the ip header for later tests and input */
tax	0:66300c77c6e9	294	/* @todo: no ip options supported? */
tax	0:66300c77c6e9	295	SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN);
tax	0:66300c77c6e9	296	return ipr;
tax	0:66300c77c6e9	297	}
tax	0:66300c77c6e9	298
tax	0:66300c77c6e9	299	/**
tax	0:66300c77c6e9	300	* Dequeues a datagram from the datagram queue. Doesn't deallocate the pbufs.
tax	0:66300c77c6e9	301	* @param ipr points to the queue entry to dequeue
tax	0:66300c77c6e9	302	*/
tax	0:66300c77c6e9	303	static void
tax	0:66300c77c6e9	304	ip_reass_dequeue_datagram(struct ip_reassdata ipr, struct ip_reassdata prev)
tax	0:66300c77c6e9	305	{
tax	0:66300c77c6e9	306
tax	0:66300c77c6e9	307	/* dequeue the reass struct */
tax	0:66300c77c6e9	308	if (reassdatagrams == ipr) {
tax	0:66300c77c6e9	309	/* it was the first in the list */
tax	0:66300c77c6e9	310	reassdatagrams = ipr->next;
tax	0:66300c77c6e9	311	} else {
tax	0:66300c77c6e9	312	/* it wasn't the first, so it must have a valid 'prev' */
tax	0:66300c77c6e9	313	LWIP_ASSERT("sanity check linked list", prev != NULL);
tax	0:66300c77c6e9	314	prev->next = ipr->next;
tax	0:66300c77c6e9	315	}
tax	0:66300c77c6e9	316
tax	0:66300c77c6e9	317	/* now we can free the ip_reass struct */
tax	0:66300c77c6e9	318	memp_free(MEMP_REASSDATA, ipr);
tax	0:66300c77c6e9	319	}
tax	0:66300c77c6e9	320
tax	0:66300c77c6e9	321	/**
tax	0:66300c77c6e9	322	* Chain a new pbuf into the pbuf list that composes the datagram. The pbuf list
tax	0:66300c77c6e9	323	* will grow over time as new pbufs are rx.
tax	0:66300c77c6e9	324	* Also checks that the datagram passes basic continuity checks (if the last
tax	0:66300c77c6e9	325	* fragment was received at least once).
tax	0:66300c77c6e9	326	* @param root_p points to the 'root' pbuf for the current datagram being assembled.
tax	0:66300c77c6e9	327	* @param new_p points to the pbuf for the current fragment
tax	0:66300c77c6e9	328	* @return 0 if invalid, >0 otherwise
tax	0:66300c77c6e9	329	*/
tax	0:66300c77c6e9	330	static int
tax	0:66300c77c6e9	331	ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata ipr, struct pbuf new_p)
tax	0:66300c77c6e9	332	{
tax	0:66300c77c6e9	333	struct ip_reass_helper iprh, iprh_tmp, *iprh_prev=NULL;
tax	0:66300c77c6e9	334	struct pbuf *q;
tax	0:66300c77c6e9	335	u16_t offset,len;
tax	0:66300c77c6e9	336	struct ip_hdr *fraghdr;
tax	0:66300c77c6e9	337	int valid = 1;
tax	0:66300c77c6e9	338
tax	0:66300c77c6e9	339	/* Extract length and fragment offset from current fragment */
tax	0:66300c77c6e9	340	fraghdr = (struct ip_hdr*)new_p->payload;
tax	0:66300c77c6e9	341	len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
tax	0:66300c77c6e9	342	offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
tax	0:66300c77c6e9	343
tax	0:66300c77c6e9	344	/* overwrite the fragment's ip header from the pbuf with our helper struct,
tax	0:66300c77c6e9	345	* and setup the embedded helper structure. */
tax	0:66300c77c6e9	346	/* make sure the struct ip_reass_helper fits into the IP header */
tax	0:66300c77c6e9	347	LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN",
tax	0:66300c77c6e9	348	sizeof(struct ip_reass_helper) <= IP_HLEN);
tax	0:66300c77c6e9	349	iprh = (struct ip_reass_helper*)new_p->payload;
tax	0:66300c77c6e9	350	iprh->next_pbuf = NULL;
tax	0:66300c77c6e9	351	iprh->start = offset;
tax	0:66300c77c6e9	352	iprh->end = offset + len;
tax	0:66300c77c6e9	353
tax	0:66300c77c6e9	354	/* Iterate through until we either get to the end of the list (append),
tax	0:66300c77c6e9	355	* or we find on with a larger offset (insert). */
tax	0:66300c77c6e9	356	for (q = ipr->p; q != NULL;) {
tax	0:66300c77c6e9	357	iprh_tmp = (struct ip_reass_helper*)q->payload;
tax	0:66300c77c6e9	358	if (iprh->start < iprh_tmp->start) {
tax	0:66300c77c6e9	359	/* the new pbuf should be inserted before this */
tax	0:66300c77c6e9	360	iprh->next_pbuf = q;
tax	0:66300c77c6e9	361	if (iprh_prev != NULL) {
tax	0:66300c77c6e9	362	/* not the fragment with the lowest offset */
tax	0:66300c77c6e9	363	#if IP_REASS_CHECK_OVERLAP
tax	0:66300c77c6e9	364	if ((iprh->start < iprh_prev->end) \|\| (iprh->end > iprh_tmp->start)) {
tax	0:66300c77c6e9	365	/* fragment overlaps with previous or following, throw away */
tax	0:66300c77c6e9	366	goto freepbuf;
tax	0:66300c77c6e9	367	}
tax	0:66300c77c6e9	368	#endif /* IP_REASS_CHECK_OVERLAP */
tax	0:66300c77c6e9	369	iprh_prev->next_pbuf = new_p;
tax	0:66300c77c6e9	370	} else {
tax	0:66300c77c6e9	371	/* fragment with the lowest offset */
tax	0:66300c77c6e9	372	ipr->p = new_p;
tax	0:66300c77c6e9	373	}
tax	0:66300c77c6e9	374	break;
tax	0:66300c77c6e9	375	} else if(iprh->start == iprh_tmp->start) {
tax	0:66300c77c6e9	376	/* received the same datagram twice: no need to keep the datagram */
tax	0:66300c77c6e9	377	goto freepbuf;
tax	0:66300c77c6e9	378	#if IP_REASS_CHECK_OVERLAP
tax	0:66300c77c6e9	379	} else if(iprh->start < iprh_tmp->end) {
tax	0:66300c77c6e9	380	/* overlap: no need to keep the new datagram */
tax	0:66300c77c6e9	381	goto freepbuf;
tax	0:66300c77c6e9	382	#endif /* IP_REASS_CHECK_OVERLAP */
tax	0:66300c77c6e9	383	} else {
tax	0:66300c77c6e9	384	/* Check if the fragments received so far have no wholes. */
tax	0:66300c77c6e9	385	if (iprh_prev != NULL) {
tax	0:66300c77c6e9	386	if (iprh_prev->end != iprh_tmp->start) {
tax	0:66300c77c6e9	387	/* There is a fragment missing between the current
tax	0:66300c77c6e9	388	* and the previous fragment */
tax	0:66300c77c6e9	389	valid = 0;
tax	0:66300c77c6e9	390	}
tax	0:66300c77c6e9	391	}
tax	0:66300c77c6e9	392	}
tax	0:66300c77c6e9	393	q = iprh_tmp->next_pbuf;
tax	0:66300c77c6e9	394	iprh_prev = iprh_tmp;
tax	0:66300c77c6e9	395	}
tax	0:66300c77c6e9	396
tax	0:66300c77c6e9	397	/* If q is NULL, then we made it to the end of the list. Determine what to do now */
tax	0:66300c77c6e9	398	if (q == NULL) {
tax	0:66300c77c6e9	399	if (iprh_prev != NULL) {
tax	0:66300c77c6e9	400	/* this is (for now), the fragment with the highest offset:
tax	0:66300c77c6e9	401	* chain it to the last fragment */
tax	0:66300c77c6e9	402	#if IP_REASS_CHECK_OVERLAP
tax	0:66300c77c6e9	403	LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
tax	0:66300c77c6e9	404	#endif /* IP_REASS_CHECK_OVERLAP */
tax	0:66300c77c6e9	405	iprh_prev->next_pbuf = new_p;
tax	0:66300c77c6e9	406	if (iprh_prev->end != iprh->start) {
tax	0:66300c77c6e9	407	valid = 0;
tax	0:66300c77c6e9	408	}
tax	0:66300c77c6e9	409	} else {
tax	0:66300c77c6e9	410	#if IP_REASS_CHECK_OVERLAP
tax	0:66300c77c6e9	411	LWIP_ASSERT("no previous fragment, this must be the first fragment!",
tax	0:66300c77c6e9	412	ipr->p == NULL);
tax	0:66300c77c6e9	413	#endif /* IP_REASS_CHECK_OVERLAP */
tax	0:66300c77c6e9	414	/* this is the first fragment we ever received for this ip datagram */
tax	0:66300c77c6e9	415	ipr->p = new_p;
tax	0:66300c77c6e9	416	}
tax	0:66300c77c6e9	417	}
tax	0:66300c77c6e9	418
tax	0:66300c77c6e9	419	/* At this point, the validation part begins: */
tax	0:66300c77c6e9	420	/* If we already received the last fragment */
tax	0:66300c77c6e9	421	if ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0) {
tax	0:66300c77c6e9	422	/* and had no wholes so far */
tax	0:66300c77c6e9	423	if (valid) {
tax	0:66300c77c6e9	424	/* then check if the rest of the fragments is here */
tax	0:66300c77c6e9	425	/* Check if the queue starts with the first datagram */
tax	0:66300c77c6e9	426	if (((struct ip_reass_helper*)ipr->p->payload)->start != 0) {
tax	0:66300c77c6e9	427	valid = 0;
tax	0:66300c77c6e9	428	} else {
tax	0:66300c77c6e9	429	/* and check that there are no wholes after this datagram */
tax	0:66300c77c6e9	430	iprh_prev = iprh;
tax	0:66300c77c6e9	431	q = iprh->next_pbuf;
tax	0:66300c77c6e9	432	while (q != NULL) {
tax	0:66300c77c6e9	433	iprh = (struct ip_reass_helper*)q->payload;
tax	0:66300c77c6e9	434	if (iprh_prev->end != iprh->start) {
tax	0:66300c77c6e9	435	valid = 0;
tax	0:66300c77c6e9	436	break;
tax	0:66300c77c6e9	437	}
tax	0:66300c77c6e9	438	iprh_prev = iprh;
tax	0:66300c77c6e9	439	q = iprh->next_pbuf;
tax	0:66300c77c6e9	440	}
tax	0:66300c77c6e9	441	/* if still valid, all fragments are received
tax	0:66300c77c6e9	442	* (because to the MF==0 already arrived */
tax	0:66300c77c6e9	443	if (valid) {
tax	0:66300c77c6e9	444	LWIP_ASSERT("sanity check", ipr->p != NULL);
tax	0:66300c77c6e9	445	LWIP_ASSERT("sanity check",
tax	0:66300c77c6e9	446	((struct ip_reass_helper*)ipr->p->payload) != iprh);
tax	0:66300c77c6e9	447	LWIP_ASSERT("validate_datagram:next_pbuf!=NULL",
tax	0:66300c77c6e9	448	iprh->next_pbuf == NULL);
tax	0:66300c77c6e9	449	LWIP_ASSERT("validate_datagram:datagram end!=datagram len",
tax	0:66300c77c6e9	450	iprh->end == ipr->datagram_len);
tax	0:66300c77c6e9	451	}
tax	0:66300c77c6e9	452	}
tax	0:66300c77c6e9	453	}
tax	0:66300c77c6e9	454	/* If valid is 0 here, there are some fragments missing in the middle
tax	0:66300c77c6e9	455	* (since MF == 0 has already arrived). Such datagrams simply time out if
tax	0:66300c77c6e9	456	* no more fragments are received... */
tax	0:66300c77c6e9	457	return valid;
tax	0:66300c77c6e9	458	}
tax	0:66300c77c6e9	459	/* If we come here, not all fragments were received, yet! */
tax	0:66300c77c6e9	460	return 0; /* not yet valid! */
tax	0:66300c77c6e9	461	#if IP_REASS_CHECK_OVERLAP
tax	0:66300c77c6e9	462	freepbuf:
tax	0:66300c77c6e9	463	ip_reass_pbufcount -= pbuf_clen(new_p);
tax	0:66300c77c6e9	464	pbuf_free(new_p);
tax	0:66300c77c6e9	465	return 0;
tax	0:66300c77c6e9	466	#endif /* IP_REASS_CHECK_OVERLAP */
tax	0:66300c77c6e9	467	}
tax	0:66300c77c6e9	468
tax	0:66300c77c6e9	469	/**
tax	0:66300c77c6e9	470	* Reassembles incoming IP fragments into an IP datagram.
tax	0:66300c77c6e9	471	*
tax	0:66300c77c6e9	472	* @param p points to a pbuf chain of the fragment
tax	0:66300c77c6e9	473	* @return NULL if reassembly is incomplete, ? otherwise
tax	0:66300c77c6e9	474	*/
tax	0:66300c77c6e9	475	struct pbuf *
tax	0:66300c77c6e9	476	ip_reass(struct pbuf *p)
tax	0:66300c77c6e9	477	{
tax	0:66300c77c6e9	478	struct pbuf *r;
tax	0:66300c77c6e9	479	struct ip_hdr *fraghdr;
tax	0:66300c77c6e9	480	struct ip_reassdata *ipr;
tax	0:66300c77c6e9	481	struct ip_reass_helper *iprh;
tax	0:66300c77c6e9	482	u16_t offset, len;
tax	0:66300c77c6e9	483	u8_t clen;
tax	0:66300c77c6e9	484	struct ip_reassdata *ipr_prev = NULL;
tax	0:66300c77c6e9	485
tax	0:66300c77c6e9	486	IPFRAG_STATS_INC(ip_frag.recv);
tax	0:66300c77c6e9	487	snmp_inc_ipreasmreqds();
tax	0:66300c77c6e9	488
tax	0:66300c77c6e9	489	fraghdr = (struct ip_hdr*)p->payload;
tax	0:66300c77c6e9	490
tax	0:66300c77c6e9	491	if ((IPH_HL(fraghdr) * 4) != IP_HLEN) {
tax	0:66300c77c6e9	492	LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n"));
tax	0:66300c77c6e9	493	IPFRAG_STATS_INC(ip_frag.err);
tax	0:66300c77c6e9	494	goto nullreturn;
tax	0:66300c77c6e9	495	}
tax	0:66300c77c6e9	496
tax	0:66300c77c6e9	497	offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
tax	0:66300c77c6e9	498	len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
tax	0:66300c77c6e9	499
tax	0:66300c77c6e9	500	/* Check if we are allowed to enqueue more datagrams. */
tax	0:66300c77c6e9	501	clen = pbuf_clen(p);
tax	0:66300c77c6e9	502	if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
tax	0:66300c77c6e9	503	#if IP_REASS_FREE_OLDEST
tax	0:66300c77c6e9	504	if (!ip_reass_remove_oldest_datagram(fraghdr, clen) \|\|
tax	0:66300c77c6e9	505	((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
tax	0:66300c77c6e9	506	#endif /* IP_REASS_FREE_OLDEST */
tax	0:66300c77c6e9	507	{
tax	0:66300c77c6e9	508	/* No datagram could be freed and still too many pbufs enqueued */
tax	0:66300c77c6e9	509	LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
tax	0:66300c77c6e9	510	ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
tax	0:66300c77c6e9	511	IPFRAG_STATS_INC(ip_frag.memerr);
tax	0:66300c77c6e9	512	/* @todo: send ICMP time exceeded here? */
tax	0:66300c77c6e9	513	/* drop this pbuf */
tax	0:66300c77c6e9	514	goto nullreturn;
tax	0:66300c77c6e9	515	}
tax	0:66300c77c6e9	516	}
tax	0:66300c77c6e9	517
tax	0:66300c77c6e9	518	/* Look for the datagram the fragment belongs to in the current datagram queue,
tax	0:66300c77c6e9	519	* remembering the previous in the queue for later dequeueing. */
tax	0:66300c77c6e9	520	for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
tax	0:66300c77c6e9	521	/* Check if the incoming fragment matches the one currently present
tax	0:66300c77c6e9	522	in the reassembly buffer. If so, we proceed with copying the
tax	0:66300c77c6e9	523	fragment into the buffer. */
tax	0:66300c77c6e9	524	if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
tax	0:66300c77c6e9	525	LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
tax	0:66300c77c6e9	526	ntohs(IPH_ID(fraghdr))));
tax	0:66300c77c6e9	527	IPFRAG_STATS_INC(ip_frag.cachehit);
tax	0:66300c77c6e9	528	break;
tax	0:66300c77c6e9	529	}
tax	0:66300c77c6e9	530	ipr_prev = ipr;
tax	0:66300c77c6e9	531	}
tax	0:66300c77c6e9	532
tax	0:66300c77c6e9	533	if (ipr == NULL) {
tax	0:66300c77c6e9	534	/* Enqueue a new datagram into the datagram queue */
tax	0:66300c77c6e9	535	ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
tax	0:66300c77c6e9	536	/* Bail if unable to enqueue */
tax	0:66300c77c6e9	537	if(ipr == NULL) {
tax	0:66300c77c6e9	538	goto nullreturn;
tax	0:66300c77c6e9	539	}
tax	0:66300c77c6e9	540	} else {
tax	0:66300c77c6e9	541	if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) &&
tax	0:66300c77c6e9	542	((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
tax	0:66300c77c6e9	543	/* ipr->iphdr is not the header from the first fragment, but fraghdr is
tax	0:66300c77c6e9	544	* -> copy fraghdr into ipr->iphdr since we want to have the header
tax	0:66300c77c6e9	545	* of the first fragment (for ICMP time exceeded and later, for copying
tax	0:66300c77c6e9	546	* all options, if supported)*/
tax	0:66300c77c6e9	547	SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
tax	0:66300c77c6e9	548	}
tax	0:66300c77c6e9	549	}
tax	0:66300c77c6e9	550	/* Track the current number of pbufs current 'in-flight', in order to limit
tax	0:66300c77c6e9	551	the number of fragments that may be enqueued at any one time */
tax	0:66300c77c6e9	552	ip_reass_pbufcount += clen;
tax	0:66300c77c6e9	553
tax	0:66300c77c6e9	554	/* At this point, we have either created a new entry or pointing
tax	0:66300c77c6e9	555	* to an existing one */
tax	0:66300c77c6e9	556
tax	0:66300c77c6e9	557	/* check for 'no more fragments', and update queue entry*/
tax	0:66300c77c6e9	558	if ((IPH_OFFSET(fraghdr) & PP_NTOHS(IP_MF)) == 0) {
tax	0:66300c77c6e9	559	ipr->flags \|= IP_REASS_FLAG_LASTFRAG;
tax	0:66300c77c6e9	560	ipr->datagram_len = offset + len;
tax	0:66300c77c6e9	561	LWIP_DEBUGF(IP_REASS_DEBUG,
tax	0:66300c77c6e9	562	("ip_reass: last fragment seen, total len %"S16_F"\n",
tax	0:66300c77c6e9	563	ipr->datagram_len));
tax	0:66300c77c6e9	564	}
tax	0:66300c77c6e9	565	/* find the right place to insert this pbuf */
tax	0:66300c77c6e9	566	/* @todo: trim pbufs if fragments are overlapping */
tax	0:66300c77c6e9	567	if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) {
tax	0:66300c77c6e9	568	/* the totally last fragment (flag more fragments = 0) was received at least
tax	0:66300c77c6e9	569	* once AND all fragments are received */
tax	0:66300c77c6e9	570	ipr->datagram_len += IP_HLEN;
tax	0:66300c77c6e9	571
tax	0:66300c77c6e9	572	/* save the second pbuf before copying the header over the pointer */
tax	0:66300c77c6e9	573	r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf;
tax	0:66300c77c6e9	574
tax	0:66300c77c6e9	575	/* copy the original ip header back to the first pbuf */
tax	0:66300c77c6e9	576	fraghdr = (struct ip_hdr*)(ipr->p->payload);
tax	0:66300c77c6e9	577	SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
tax	0:66300c77c6e9	578	IPH_LEN_SET(fraghdr, htons(ipr->datagram_len));
tax	0:66300c77c6e9	579	IPH_OFFSET_SET(fraghdr, 0);
tax	0:66300c77c6e9	580	IPH_CHKSUM_SET(fraghdr, 0);
tax	0:66300c77c6e9	581	/* @todo: do we need to set calculate the correct checksum? */
tax	0:66300c77c6e9	582	IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));
tax	0:66300c77c6e9	583
tax	0:66300c77c6e9	584	p = ipr->p;
tax	0:66300c77c6e9	585
tax	0:66300c77c6e9	586	/* chain together the pbufs contained within the reass_data list. */
tax	0:66300c77c6e9	587	while(r != NULL) {
tax	0:66300c77c6e9	588	iprh = (struct ip_reass_helper*)r->payload;
tax	0:66300c77c6e9	589
tax	0:66300c77c6e9	590	/* hide the ip header for every succeding fragment */
tax	0:66300c77c6e9	591	pbuf_header(r, -IP_HLEN);
tax	0:66300c77c6e9	592	pbuf_cat(p, r);
tax	0:66300c77c6e9	593	r = iprh->next_pbuf;
tax	0:66300c77c6e9	594	}
tax	0:66300c77c6e9	595	/* release the sources allocate for the fragment queue entry */
tax	0:66300c77c6e9	596	ip_reass_dequeue_datagram(ipr, ipr_prev);
tax	0:66300c77c6e9	597
tax	0:66300c77c6e9	598	/* and adjust the number of pbufs currently queued for reassembly. */
tax	0:66300c77c6e9	599	ip_reass_pbufcount -= pbuf_clen(p);
tax	0:66300c77c6e9	600
tax	0:66300c77c6e9	601	/* Return the pbuf chain */
tax	0:66300c77c6e9	602	return p;
tax	0:66300c77c6e9	603	}
tax	0:66300c77c6e9	604	/* the datagram is not (yet?) reassembled completely */
tax	0:66300c77c6e9	605	LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
tax	0:66300c77c6e9	606	return NULL;
tax	0:66300c77c6e9	607
tax	0:66300c77c6e9	608	nullreturn:
tax	0:66300c77c6e9	609	LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n"));
tax	0:66300c77c6e9	610	IPFRAG_STATS_INC(ip_frag.drop);
tax	0:66300c77c6e9	611	pbuf_free(p);
tax	0:66300c77c6e9	612	return NULL;
tax	0:66300c77c6e9	613	}
tax	0:66300c77c6e9	614	#endif /* IP_REASSEMBLY */
tax	0:66300c77c6e9	615
tax	0:66300c77c6e9	616	#if IP_FRAG
tax	0:66300c77c6e9	617	#if IP_FRAG_USES_STATIC_BUF
tax	0:66300c77c6e9	618	static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU + MEM_ALIGNMENT - 1)];
tax	0:66300c77c6e9	619	#else /* IP_FRAG_USES_STATIC_BUF */
tax	0:66300c77c6e9	620
tax	0:66300c77c6e9	621	#if !LWIP_NETIF_TX_SINGLE_PBUF
tax	0:66300c77c6e9	622	/** Allocate a new struct pbuf_custom_ref */
tax	0:66300c77c6e9	623	static struct pbuf_custom_ref*
tax	0:66300c77c6e9	624	ip_frag_alloc_pbuf_custom_ref(void)
tax	0:66300c77c6e9	625	{
tax	0:66300c77c6e9	626	return (struct pbuf_custom_ref*)memp_malloc(MEMP_FRAG_PBUF);
tax	0:66300c77c6e9	627	}
tax	0:66300c77c6e9	628
tax	0:66300c77c6e9	629	/** Free a struct pbuf_custom_ref */
tax	0:66300c77c6e9	630	static void
tax	0:66300c77c6e9	631	ip_frag_free_pbuf_custom_ref(struct pbuf_custom_ref* p)
tax	0:66300c77c6e9	632	{
tax	0:66300c77c6e9	633	LWIP_ASSERT("p != NULL", p != NULL);
tax	0:66300c77c6e9	634	memp_free(MEMP_FRAG_PBUF, p);
tax	0:66300c77c6e9	635	}
tax	0:66300c77c6e9	636
tax	0:66300c77c6e9	637	/** Free-callback function to free a 'struct pbuf_custom_ref', called by
tax	0:66300c77c6e9	638	* pbuf_free. */
tax	0:66300c77c6e9	639	static void
tax	0:66300c77c6e9	640	ipfrag_free_pbuf_custom(struct pbuf *p)
tax	0:66300c77c6e9	641	{
tax	0:66300c77c6e9	642	struct pbuf_custom_ref pcr = (struct pbuf_custom_ref)p;
tax	0:66300c77c6e9	643	LWIP_ASSERT("pcr != NULL", pcr != NULL);
tax	0:66300c77c6e9	644	LWIP_ASSERT("pcr == p", (void)pcr == (void)p);
tax	0:66300c77c6e9	645	if (pcr->original != NULL) {
tax	0:66300c77c6e9	646	pbuf_free(pcr->original);
tax	0:66300c77c6e9	647	}
tax	0:66300c77c6e9	648	ip_frag_free_pbuf_custom_ref(pcr);
tax	0:66300c77c6e9	649	}
tax	0:66300c77c6e9	650	#endif /* !LWIP_NETIF_TX_SINGLE_PBUF */
tax	0:66300c77c6e9	651	#endif /* IP_FRAG_USES_STATIC_BUF */
tax	0:66300c77c6e9	652
tax	0:66300c77c6e9	653	/**
tax	0:66300c77c6e9	654	* Fragment an IP datagram if too large for the netif.
tax	0:66300c77c6e9	655	*
tax	0:66300c77c6e9	656	* Chop the datagram in MTU sized chunks and send them in order
tax	0:66300c77c6e9	657	* by using a fixed size static memory buffer (PBUF_REF) or
tax	0:66300c77c6e9	658	* point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF).
tax	0:66300c77c6e9	659	*
tax	0:66300c77c6e9	660	* @param p ip packet to send
tax	0:66300c77c6e9	661	* @param netif the netif on which to send
tax	0:66300c77c6e9	662	* @param dest destination ip address to which to send
tax	0:66300c77c6e9	663	*
tax	0:66300c77c6e9	664	* @return ERR_OK if sent successfully, err_t otherwise
tax	0:66300c77c6e9	665	*/
tax	0:66300c77c6e9	666	err_t
tax	0:66300c77c6e9	667	ip_frag(struct pbuf p, struct netif netif, ip_addr_t *dest)
tax	0:66300c77c6e9	668	{
tax	0:66300c77c6e9	669	struct pbuf *rambuf;
tax	0:66300c77c6e9	670	#if IP_FRAG_USES_STATIC_BUF
tax	0:66300c77c6e9	671	struct pbuf *header;
tax	0:66300c77c6e9	672	#else
tax	0:66300c77c6e9	673	#if !LWIP_NETIF_TX_SINGLE_PBUF
tax	0:66300c77c6e9	674	struct pbuf *newpbuf;
tax	0:66300c77c6e9	675	#endif
tax	0:66300c77c6e9	676	struct ip_hdr *original_iphdr;
tax	0:66300c77c6e9	677	#endif
tax	0:66300c77c6e9	678	struct ip_hdr *iphdr;
tax	0:66300c77c6e9	679	u16_t nfb;
tax	0:66300c77c6e9	680	u16_t left, cop;
tax	0:66300c77c6e9	681	u16_t mtu = netif->mtu;
tax	0:66300c77c6e9	682	u16_t ofo, omf;
tax	0:66300c77c6e9	683	u16_t last;
tax	0:66300c77c6e9	684	u16_t poff = IP_HLEN;
tax	0:66300c77c6e9	685	u16_t tmp;
tax	0:66300c77c6e9	686	#if !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF
tax	0:66300c77c6e9	687	u16_t newpbuflen = 0;
tax	0:66300c77c6e9	688	u16_t left_to_copy;
tax	0:66300c77c6e9	689	#endif
tax	0:66300c77c6e9	690
tax	0:66300c77c6e9	691	/* Get a RAM based MTU sized pbuf */
tax	0:66300c77c6e9	692	#if IP_FRAG_USES_STATIC_BUF
tax	0:66300c77c6e9	693	/* When using a static buffer, we use a PBUF_REF, which we will
tax	0:66300c77c6e9	694	* use to reference the packet (without link header).
tax	0:66300c77c6e9	695	* Layer and length is irrelevant.
tax	0:66300c77c6e9	696	*/
tax	0:66300c77c6e9	697	rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
tax	0:66300c77c6e9	698	if (rambuf == NULL) {
tax	0:66300c77c6e9	699	LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n"));
tax	0:66300c77c6e9	700	return ERR_MEM;
tax	0:66300c77c6e9	701	}
tax	0:66300c77c6e9	702	rambuf->tot_len = rambuf->len = mtu;
tax	0:66300c77c6e9	703	rambuf->payload = LWIP_MEM_ALIGN((void *)buf);
tax	0:66300c77c6e9	704
tax	0:66300c77c6e9	705	/* Copy the IP header in it */
tax	0:66300c77c6e9	706	iphdr = (struct ip_hdr *)rambuf->payload;
tax	0:66300c77c6e9	707	SMEMCPY(iphdr, p->payload, IP_HLEN);
tax	0:66300c77c6e9	708	#else /* IP_FRAG_USES_STATIC_BUF */
tax	0:66300c77c6e9	709	original_iphdr = (struct ip_hdr *)p->payload;
tax	0:66300c77c6e9	710	iphdr = original_iphdr;
tax	0:66300c77c6e9	711	#endif /* IP_FRAG_USES_STATIC_BUF */
tax	0:66300c77c6e9	712
tax	0:66300c77c6e9	713	/* Save original offset */
tax	0:66300c77c6e9	714	tmp = ntohs(IPH_OFFSET(iphdr));
tax	0:66300c77c6e9	715	ofo = tmp & IP_OFFMASK;
tax	0:66300c77c6e9	716	omf = tmp & IP_MF;
tax	0:66300c77c6e9	717
tax	0:66300c77c6e9	718	left = p->tot_len - IP_HLEN;
tax	0:66300c77c6e9	719
tax	0:66300c77c6e9	720	nfb = (mtu - IP_HLEN) / 8;
tax	0:66300c77c6e9	721
tax	0:66300c77c6e9	722	while (left) {
tax	0:66300c77c6e9	723	last = (left <= mtu - IP_HLEN);
tax	0:66300c77c6e9	724
tax	0:66300c77c6e9	725	/* Set new offset and MF flag */
tax	0:66300c77c6e9	726	tmp = omf \| (IP_OFFMASK & (ofo));
tax	0:66300c77c6e9	727	if (!last) {
tax	0:66300c77c6e9	728	tmp = tmp \| IP_MF;
tax	0:66300c77c6e9	729	}
tax	0:66300c77c6e9	730
tax	0:66300c77c6e9	731	/* Fill this fragment */
tax	0:66300c77c6e9	732	cop = last ? left : nfb * 8;
tax	0:66300c77c6e9	733
tax	0:66300c77c6e9	734	#if IP_FRAG_USES_STATIC_BUF
tax	0:66300c77c6e9	735	poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
tax	0:66300c77c6e9	736	#else /* IP_FRAG_USES_STATIC_BUF */
tax	0:66300c77c6e9	737	#if LWIP_NETIF_TX_SINGLE_PBUF
tax	0:66300c77c6e9	738	rambuf = pbuf_alloc(PBUF_IP, cop, PBUF_RAM);
tax	0:66300c77c6e9	739	if (rambuf == NULL) {
tax	0:66300c77c6e9	740	return ERR_MEM;
tax	0:66300c77c6e9	741	}
tax	0:66300c77c6e9	742	LWIP_ASSERT("this needs a pbuf in one piece!",
tax	0:66300c77c6e9	743	(rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
tax	0:66300c77c6e9	744	poff += pbuf_copy_partial(p, rambuf->payload, cop, poff);
tax	0:66300c77c6e9	745	/* make room for the IP header */
tax	0:66300c77c6e9	746	if(pbuf_header(rambuf, IP_HLEN)) {
tax	0:66300c77c6e9	747	pbuf_free(rambuf);
tax	0:66300c77c6e9	748	return ERR_MEM;
tax	0:66300c77c6e9	749	}
tax	0:66300c77c6e9	750	/* fill in the IP header */
tax	0:66300c77c6e9	751	SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
tax	0:66300c77c6e9	752	iphdr = rambuf->payload;
tax	0:66300c77c6e9	753	#else /* LWIP_NETIF_TX_SINGLE_PBUF */
tax	0:66300c77c6e9	754	/* When not using a static buffer, create a chain of pbufs.
tax	0:66300c77c6e9	755	* The first will be a PBUF_RAM holding the link and IP header.
tax	0:66300c77c6e9	756	* The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
tax	0:66300c77c6e9	757	* but limited to the size of an mtu.
tax	0:66300c77c6e9	758	*/
tax	0:66300c77c6e9	759	rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
tax	0:66300c77c6e9	760	if (rambuf == NULL) {
tax	0:66300c77c6e9	761	return ERR_MEM;
tax	0:66300c77c6e9	762	}
tax	0:66300c77c6e9	763	LWIP_ASSERT("this needs a pbuf in one piece!",
tax	0:66300c77c6e9	764	(p->len >= (IP_HLEN)));
tax	0:66300c77c6e9	765	SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
tax	0:66300c77c6e9	766	iphdr = (struct ip_hdr *)rambuf->payload;
tax	0:66300c77c6e9	767
tax	0:66300c77c6e9	768	/* Can just adjust p directly for needed offset. */
tax	0:66300c77c6e9	769	p->payload = (u8_t *)p->payload + poff;
tax	0:66300c77c6e9	770	p->len -= poff;
tax	0:66300c77c6e9	771
tax	0:66300c77c6e9	772	left_to_copy = cop;
tax	0:66300c77c6e9	773	while (left_to_copy) {
tax	0:66300c77c6e9	774	struct pbuf_custom_ref *pcr;
tax	0:66300c77c6e9	775	newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
tax	0:66300c77c6e9	776	/* Is this pbuf already empty? */
tax	0:66300c77c6e9	777	if (!newpbuflen) {
tax	0:66300c77c6e9	778	p = p->next;
tax	0:66300c77c6e9	779	continue;
tax	0:66300c77c6e9	780	}
tax	0:66300c77c6e9	781	pcr = ip_frag_alloc_pbuf_custom_ref();
tax	0:66300c77c6e9	782	if (pcr == NULL) {
tax	0:66300c77c6e9	783	pbuf_free(rambuf);
tax	0:66300c77c6e9	784	return ERR_MEM;
tax	0:66300c77c6e9	785	}
tax	0:66300c77c6e9	786	/* Mirror this pbuf, although we might not need all of it. */
tax	0:66300c77c6e9	787	newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
tax	0:66300c77c6e9	788	if (newpbuf == NULL) {
tax	0:66300c77c6e9	789	ip_frag_free_pbuf_custom_ref(pcr);
tax	0:66300c77c6e9	790	pbuf_free(rambuf);
tax	0:66300c77c6e9	791	return ERR_MEM;
tax	0:66300c77c6e9	792	}
tax	0:66300c77c6e9	793	pbuf_ref(p);
tax	0:66300c77c6e9	794	pcr->original = p;
tax	0:66300c77c6e9	795	pcr->pc.custom_free_function = ipfrag_free_pbuf_custom;
tax	0:66300c77c6e9	796
tax	0:66300c77c6e9	797	/* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
tax	0:66300c77c6e9	798	* so that it is removed when pbuf_dechain is later called on rambuf.
tax	0:66300c77c6e9	799	*/
tax	0:66300c77c6e9	800	pbuf_cat(rambuf, newpbuf);
tax	0:66300c77c6e9	801	left_to_copy -= newpbuflen;
tax	0:66300c77c6e9	802	if (left_to_copy) {
tax	0:66300c77c6e9	803	p = p->next;
tax	0:66300c77c6e9	804	}
tax	0:66300c77c6e9	805	}
tax	0:66300c77c6e9	806	poff = newpbuflen;
tax	0:66300c77c6e9	807	#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
tax	0:66300c77c6e9	808	#endif /* IP_FRAG_USES_STATIC_BUF */
tax	0:66300c77c6e9	809
tax	0:66300c77c6e9	810	/* Correct header */
tax	0:66300c77c6e9	811	IPH_OFFSET_SET(iphdr, htons(tmp));
tax	0:66300c77c6e9	812	IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
tax	0:66300c77c6e9	813	IPH_CHKSUM_SET(iphdr, 0);
tax	0:66300c77c6e9	814	IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
tax	0:66300c77c6e9	815
tax	0:66300c77c6e9	816	#if IP_FRAG_USES_STATIC_BUF
tax	0:66300c77c6e9	817	if (last) {
tax	0:66300c77c6e9	818	pbuf_realloc(rambuf, left + IP_HLEN);
tax	0:66300c77c6e9	819	}
tax	0:66300c77c6e9	820
tax	0:66300c77c6e9	821	/* This part is ugly: we alloc a RAM based pbuf for
tax	0:66300c77c6e9	822	* the link level header for each chunk and then
tax	0:66300c77c6e9	823	* free it.A PBUF_ROM style pbuf for which pbuf_header
tax	0:66300c77c6e9	824	* worked would make things simpler.
tax	0:66300c77c6e9	825	*/
tax	0:66300c77c6e9	826	header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
tax	0:66300c77c6e9	827	if (header != NULL) {
tax	0:66300c77c6e9	828	pbuf_chain(header, rambuf);
tax	0:66300c77c6e9	829	netif->output(netif, header, dest);
tax	0:66300c77c6e9	830	IPFRAG_STATS_INC(ip_frag.xmit);
tax	0:66300c77c6e9	831	snmp_inc_ipfragcreates();
tax	0:66300c77c6e9	832	pbuf_free(header);
tax	0:66300c77c6e9	833	} else {
tax	0:66300c77c6e9	834	LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
tax	0:66300c77c6e9	835	pbuf_free(rambuf);
tax	0:66300c77c6e9	836	return ERR_MEM;
tax	0:66300c77c6e9	837	}
tax	0:66300c77c6e9	838	#else /* IP_FRAG_USES_STATIC_BUF */
tax	0:66300c77c6e9	839	/* No need for separate header pbuf - we allowed room for it in rambuf
tax	0:66300c77c6e9	840	* when allocated.
tax	0:66300c77c6e9	841	*/
tax	0:66300c77c6e9	842	netif->output(netif, rambuf, dest);
tax	0:66300c77c6e9	843	IPFRAG_STATS_INC(ip_frag.xmit);
tax	0:66300c77c6e9	844
tax	0:66300c77c6e9	845	/* Unfortunately we can't reuse rambuf - the hardware may still be
tax	0:66300c77c6e9	846	* using the buffer. Instead we free it (and the ensuing chain) and
tax	0:66300c77c6e9	847	* recreate it next time round the loop. If we're lucky the hardware
tax	0:66300c77c6e9	848	* will have already sent the packet, the free will really free, and
tax	0:66300c77c6e9	849	* there will be zero memory penalty.
tax	0:66300c77c6e9	850	*/
tax	0:66300c77c6e9	851
tax	0:66300c77c6e9	852	pbuf_free(rambuf);
tax	0:66300c77c6e9	853	#endif /* IP_FRAG_USES_STATIC_BUF */
tax	0:66300c77c6e9	854	left -= cop;
tax	0:66300c77c6e9	855	ofo += nfb;
tax	0:66300c77c6e9	856	}
tax	0:66300c77c6e9	857	#if IP_FRAG_USES_STATIC_BUF
tax	0:66300c77c6e9	858	pbuf_free(rambuf);
tax	0:66300c77c6e9	859	#endif /* IP_FRAG_USES_STATIC_BUF */
tax	0:66300c77c6e9	860	snmp_inc_ipfragoks();
tax	0:66300c77c6e9	861	return ERR_OK;
tax	0:66300c77c6e9	862	}
tax	0:66300c77c6e9	863	#endif /* IP_FRAG */

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	29 Mar 2011
Imports:	16
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	1
Followers:	2

lwip/core/ipv4/ip_frag.c@0:66300c77c6e9, 2011-03-29 (annotated)

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