commit a4a41b9023ef5b3a7c4a1cd82fb167fc63e706df Author: goldsimon <goldsimon@gmx.de> Date: Wed Sep 26 21:50:42 2012 +0200 - This also brings in LwIP's IPv6 codebase Signed-off-by: Tomas Hruby <tom@minix3.org>
697 lines
22 KiB
C
697 lines
22 KiB
C
/**
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* @file
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*
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* IPv6 fragmentation and reassembly.
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*/
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/*
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* Copyright (c) 2010 Inico Technologies Ltd.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* This file is part of the lwIP TCP/IP stack.
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*
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* Author: Ivan Delamer <delamer@inicotech.com>
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*
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*
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* Please coordinate changes and requests with Ivan Delamer
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* <delamer@inicotech.com>
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*/
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#include "lwip/opt.h"
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#include "lwip/ip6_frag.h"
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#include "lwip/ip6.h"
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#include "lwip/icmp6.h"
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#include "lwip/nd6.h"
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#include "lwip/pbuf.h"
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#include "lwip/memp.h"
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#include "lwip/stats.h"
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#include <string.h>
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#if LWIP_IPV6 && LWIP_IPV6_REASS /* don't build if not configured for use in lwipopts.h */
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/** Setting this to 0, you can turn off checking the fragments for overlapping
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* regions. The code gets a little smaller. Only use this if you know that
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* overlapping won't occur on your network! */
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#ifndef IP_REASS_CHECK_OVERLAP
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#define IP_REASS_CHECK_OVERLAP 1
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#endif /* IP_REASS_CHECK_OVERLAP */
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/** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
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* full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
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* Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
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* is set to 1, so one datagram can be reassembled at a time, only. */
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#ifndef IP_REASS_FREE_OLDEST
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#define IP_REASS_FREE_OLDEST 1
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#endif /* IP_REASS_FREE_OLDEST */
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#define IP_REASS_FLAG_LASTFRAG 0x01
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/** This is a helper struct which holds the starting
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* offset and the ending offset of this fragment to
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* easily chain the fragments.
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* It has the same packing requirements as the IPv6 header, since it replaces
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* the Fragment Header in memory in incoming fragments to keep
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* track of the various fragments.
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*/
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#ifdef PACK_STRUCT_USE_INCLUDES
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# include "arch/bpstruct.h"
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#endif
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PACK_STRUCT_BEGIN
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struct ip6_reass_helper {
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PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
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PACK_STRUCT_FIELD(u16_t start);
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PACK_STRUCT_FIELD(u16_t end);
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} PACK_STRUCT_STRUCT;
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PACK_STRUCT_END
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#ifdef PACK_STRUCT_USE_INCLUDES
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# include "arch/epstruct.h"
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#endif
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/* static variables */
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static struct ip6_reassdata *reassdatagrams;
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static u16_t ip6_reass_pbufcount;
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/* Forward declarations. */
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static void ip6_reass_free_complete_datagram(struct ip6_reassdata *ipr);
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#if IP_REASS_FREE_OLDEST
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static void ip6_reass_remove_oldest_datagram(struct ip6_reassdata *ipr, int pbufs_needed);
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#endif /* IP_REASS_FREE_OLDEST */
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void
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ip6_reass_tmr(void)
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{
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struct ip6_reassdata *r, *tmp;
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r = reassdatagrams;
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while (r != NULL) {
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/* Decrement the timer. Once it reaches 0,
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* clean up the incomplete fragment assembly */
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if (r->timer > 0) {
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r->timer--;
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r = r->next;
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} else {
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/* reassembly timed out */
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tmp = r;
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/* get the next pointer before freeing */
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r = r->next;
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/* free the helper struct and all enqueued pbufs */
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ip6_reass_free_complete_datagram(tmp);
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}
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}
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}
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/**
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* Free a datagram (struct ip6_reassdata) and all its pbufs.
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* Updates the total count of enqueued pbufs (ip6_reass_pbufcount),
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* sends an ICMP time exceeded packet.
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*
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* @param ipr datagram to free
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*/
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static void
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ip6_reass_free_complete_datagram(struct ip6_reassdata *ipr)
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{
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struct ip6_reassdata *prev;
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u16_t pbufs_freed = 0;
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u8_t clen;
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struct pbuf *p;
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struct ip6_reass_helper *iprh;
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#if LWIP_ICMP6
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iprh = (struct ip6_reass_helper *)ipr->p->payload;
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if (iprh->start == 0) {
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/* The first fragment was received, send ICMP time exceeded. */
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/* First, de-queue the first pbuf from r->p. */
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p = ipr->p;
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ipr->p = iprh->next_pbuf;
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/* Then, move back to the original header (we are now pointing to Fragment header). */
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if (pbuf_header(p, (u8_t*)p->payload - (u8_t*)ipr->iphdr)) {
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LWIP_ASSERT("ip6_reass_free: moving p->payload to ip6 header failed\n", 0);
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}
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else {
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icmp6_time_exceeded(p, ICMP6_TE_FRAG);
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}
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clen = pbuf_clen(p);
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LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
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pbufs_freed += clen;
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pbuf_free(p);
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}
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#endif /* LWIP_ICMP6 */
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/* First, free all received pbufs. The individual pbufs need to be released
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separately as they have not yet been chained */
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p = ipr->p;
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while (p != NULL) {
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struct pbuf *pcur;
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iprh = (struct ip6_reass_helper *)p->payload;
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pcur = p;
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/* get the next pointer before freeing */
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p = iprh->next_pbuf;
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clen = pbuf_clen(pcur);
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LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
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pbufs_freed += clen;
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pbuf_free(pcur);
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}
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/* Then, unchain the struct ip6_reassdata from the list and free it. */
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if (ipr == reassdatagrams) {
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reassdatagrams = ipr->next;
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} else {
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prev = reassdatagrams;
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while (prev != NULL) {
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if (prev->next == ipr) {
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break;
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}
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prev = prev->next;
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}
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if (prev != NULL) {
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prev->next = ipr->next;
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}
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}
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memp_free(MEMP_IP6_REASSDATA, ipr);
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/* Finally, update number of pbufs in reassembly queue */
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LWIP_ASSERT("ip_reass_pbufcount >= clen", ip6_reass_pbufcount >= pbufs_freed);
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ip6_reass_pbufcount -= pbufs_freed;
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}
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#if IP_REASS_FREE_OLDEST
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/**
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* Free the oldest datagram to make room for enqueueing new fragments.
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* The datagram ipr is not freed!
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*
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* @param ipr ip6_reassdata for the current fragment
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* @param pbufs_needed number of pbufs needed to enqueue
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* (used for freeing other datagrams if not enough space)
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*/
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static void
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ip6_reass_remove_oldest_datagram(struct ip6_reassdata *ipr, int pbufs_needed)
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{
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struct ip6_reassdata *r, *oldest;
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/* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
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* but don't free the current datagram! */
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do {
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r = oldest = reassdatagrams;
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while (r != NULL) {
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if (r != ipr) {
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if (r->timer <= oldest->timer) {
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/* older than the previous oldest */
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oldest = r;
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}
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}
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r = r->next;
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}
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if (oldest != NULL) {
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ip6_reass_free_complete_datagram(oldest);
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}
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} while (((ip6_reass_pbufcount + pbufs_needed) > IP_REASS_MAX_PBUFS) && (reassdatagrams != NULL));
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}
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#endif /* IP_REASS_FREE_OLDEST */
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/**
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* Reassembles incoming IPv6 fragments into an IPv6 datagram.
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*
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* @param p points to the IPv6 Fragment Header
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* @param len the length of the payload (after Fragment Header)
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* @return NULL if reassembly is incomplete, pbuf pointing to
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* IPv6 Header if reassembly is complete
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*/
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struct pbuf *
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ip6_reass(struct pbuf *p)
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{
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struct ip6_reassdata *ipr, *ipr_prev;
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struct ip6_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
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struct ip6_frag_hdr * frag_hdr;
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u16_t offset, len;
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u8_t clen, valid = 1;
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struct pbuf *q;
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IP6_FRAG_STATS_INC(ip6_frag.recv);
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frag_hdr = (struct ip6_frag_hdr *) p->payload;
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clen = pbuf_clen(p);
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offset = ntohs(frag_hdr->_fragment_offset);
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/* Calculate fragment length from IPv6 payload length.
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* Adjust for headers before Fragment Header.
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* And finally adjust by Fragment Header length. */
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len = ntohs(ip6_current_header()->_plen);
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len -= ((u8_t*)p->payload - (u8_t*)ip6_current_header()) - IP6_HLEN;
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len -= IP6_FRAG_HLEN;
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/* Look for the datagram the fragment belongs to in the current datagram queue,
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* remembering the previous in the queue for later dequeueing. */
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for (ipr = reassdatagrams, ipr_prev = NULL; ipr != NULL; ipr = ipr->next) {
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/* Check if the incoming fragment matches the one currently present
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in the reassembly buffer. If so, we proceed with copying the
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fragment into the buffer. */
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if ((frag_hdr->_identification == ipr->identification) &&
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ip6_addr_cmp(ip6_current_src_addr(), &(ipr->iphdr->src)) &&
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ip6_addr_cmp(ip6_current_dest_addr(), &(ipr->iphdr->dest))) {
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IP6_FRAG_STATS_INC(ip6_frag.cachehit);
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break;
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}
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ipr_prev = ipr;
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}
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if (ipr == NULL) {
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/* Enqueue a new datagram into the datagram queue */
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ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
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if (ipr == NULL) {
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#if IP_REASS_FREE_OLDEST
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/* Make room and try again. */
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ip6_reass_remove_oldest_datagram(ipr, clen);
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ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
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if (ipr == NULL)
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#endif /* IP_REASS_FREE_OLDEST */
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{
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IP6_FRAG_STATS_INC(ip6_frag.memerr);
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IP6_FRAG_STATS_INC(ip6_frag.drop);
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goto nullreturn;
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}
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}
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memset(ipr, 0, sizeof(struct ip6_reassdata));
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ipr->timer = IP_REASS_MAXAGE;
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/* enqueue the new structure to the front of the list */
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ipr->next = reassdatagrams;
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reassdatagrams = ipr;
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/* Use the current IPv6 header for src/dest address reference.
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* Eventually, we will replace it when we get the first fragment
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* (it might be this one, in any case, it is done later). */
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ipr->iphdr = (struct ip6_hdr *)ip6_current_header();
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/* copy the fragmented packet id. */
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ipr->identification = frag_hdr->_identification;
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/* copy the nexth field */
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ipr->nexth = frag_hdr->_nexth;
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}
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/* Check if we are allowed to enqueue more datagrams. */
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if ((ip6_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
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#if IP_REASS_FREE_OLDEST
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ip6_reass_remove_oldest_datagram(ipr, clen);
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if ((ip6_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS)
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#endif /* IP_REASS_FREE_OLDEST */
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{
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/* @todo: send ICMPv6 time exceeded here? */
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/* drop this pbuf */
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IP6_FRAG_STATS_INC(ip6_frag.memerr);
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IP6_FRAG_STATS_INC(ip6_frag.drop);
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goto nullreturn;
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}
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}
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/* Overwrite Fragment Header with our own helper struct. */
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iprh = (struct ip6_reass_helper *)p->payload;
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iprh->next_pbuf = NULL;
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iprh->start = (offset & IP6_FRAG_OFFSET_MASK);
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iprh->end = (offset & IP6_FRAG_OFFSET_MASK) + len;
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/* find the right place to insert this pbuf */
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/* Iterate through until we either get to the end of the list (append),
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* or we find on with a larger offset (insert). */
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for (q = ipr->p; q != NULL;) {
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iprh_tmp = (struct ip6_reass_helper*)q->payload;
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if (iprh->start < iprh_tmp->start) {
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#if IP_REASS_CHECK_OVERLAP
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if (iprh->end > iprh_tmp->start) {
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/* fragment overlaps with following, throw away */
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IP6_FRAG_STATS_INC(ip6_frag.proterr);
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IP6_FRAG_STATS_INC(ip6_frag.drop);
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goto nullreturn;
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}
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if (iprh_prev != NULL) {
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if (iprh->start < iprh_prev->end) {
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/* fragment overlaps with previous, throw away */
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IP6_FRAG_STATS_INC(ip6_frag.proterr);
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IP6_FRAG_STATS_INC(ip6_frag.drop);
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goto nullreturn;
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}
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}
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#endif /* IP_REASS_CHECK_OVERLAP */
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/* the new pbuf should be inserted before this */
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iprh->next_pbuf = q;
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if (iprh_prev != NULL) {
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/* not the fragment with the lowest offset */
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iprh_prev->next_pbuf = p;
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} else {
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/* fragment with the lowest offset */
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ipr->p = p;
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}
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break;
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} else if(iprh->start == iprh_tmp->start) {
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/* received the same datagram twice: no need to keep the datagram */
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IP6_FRAG_STATS_INC(ip6_frag.drop);
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goto nullreturn;
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#if IP_REASS_CHECK_OVERLAP
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} else if(iprh->start < iprh_tmp->end) {
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/* overlap: no need to keep the new datagram */
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IP6_FRAG_STATS_INC(ip6_frag.proterr);
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IP6_FRAG_STATS_INC(ip6_frag.drop);
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goto nullreturn;
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#endif /* IP_REASS_CHECK_OVERLAP */
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} else {
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/* Check if the fragments received so far have no gaps. */
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if (iprh_prev != NULL) {
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if (iprh_prev->end != iprh_tmp->start) {
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/* There is a fragment missing between the current
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* and the previous fragment */
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valid = 0;
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}
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}
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}
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q = iprh_tmp->next_pbuf;
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iprh_prev = iprh_tmp;
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}
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/* If q is NULL, then we made it to the end of the list. Determine what to do now */
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if (q == NULL) {
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if (iprh_prev != NULL) {
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/* this is (for now), the fragment with the highest offset:
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* chain it to the last fragment */
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#if IP_REASS_CHECK_OVERLAP
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LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
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#endif /* IP_REASS_CHECK_OVERLAP */
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iprh_prev->next_pbuf = p;
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if (iprh_prev->end != iprh->start) {
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valid = 0;
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}
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} else {
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#if IP_REASS_CHECK_OVERLAP
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LWIP_ASSERT("no previous fragment, this must be the first fragment!",
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ipr->p == NULL);
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#endif /* IP_REASS_CHECK_OVERLAP */
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/* this is the first fragment we ever received for this ip datagram */
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ipr->p = p;
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}
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}
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/* Track the current number of pbufs current 'in-flight', in order to limit
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the number of fragments that may be enqueued at any one time */
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ip6_reass_pbufcount += clen;
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/* Remember IPv6 header if this is the first fragment. */
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if (iprh->start == 0) {
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ipr->iphdr = (struct ip6_hdr *)ip6_current_header();
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}
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/* If this is the last fragment, calculate total packet length. */
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if ((offset & IP6_FRAG_MORE_FLAG) == 0) {
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ipr->datagram_len = iprh->end;
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}
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/* Additional validity tests: we have received first and last fragment. */
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iprh_tmp = (struct ip6_reass_helper*)ipr->p->payload;
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if (iprh_tmp->start != 0) {
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valid = 0;
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}
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if (ipr->datagram_len == 0) {
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valid = 0;
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}
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/* Final validity test: no gaps between current and last fragment. */
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iprh_prev = iprh;
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q = iprh->next_pbuf;
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while ((q != NULL) && valid) {
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iprh = (struct ip6_reass_helper*)q->payload;
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if (iprh_prev->end != iprh->start) {
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valid = 0;
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break;
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}
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iprh_prev = iprh;
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q = iprh->next_pbuf;
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}
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if (valid) {
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/* All fragments have been received */
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/* chain together the pbufs contained within the ip6_reassdata list. */
|
|
iprh = (struct ip6_reass_helper*) ipr->p->payload;
|
|
while(iprh != NULL) {
|
|
|
|
if (iprh->next_pbuf != NULL) {
|
|
/* Save next helper struct (will be hidden in next step). */
|
|
iprh_tmp = (struct ip6_reass_helper*) iprh->next_pbuf->payload;
|
|
|
|
/* hide the fragment header for every succeding fragment */
|
|
pbuf_header(iprh->next_pbuf, -IP6_FRAG_HLEN);
|
|
pbuf_cat(ipr->p, iprh->next_pbuf);
|
|
}
|
|
else {
|
|
iprh_tmp = NULL;
|
|
}
|
|
|
|
iprh = iprh_tmp;
|
|
}
|
|
|
|
/* Adjust datagram length by adding header lengths. */
|
|
ipr->datagram_len += ((u8_t*)ipr->p->payload - (u8_t*)ipr->iphdr)
|
|
+ IP6_FRAG_HLEN
|
|
- IP6_HLEN ;
|
|
|
|
/* Set payload length in ip header. */
|
|
ipr->iphdr->_plen = htons(ipr->datagram_len);
|
|
|
|
/* Get the furst pbuf. */
|
|
p = ipr->p;
|
|
|
|
/* Restore Fragment Header in first pbuf. Mark as "single fragment"
|
|
* packet. Restore nexth. */
|
|
frag_hdr = (struct ip6_frag_hdr *) p->payload;
|
|
frag_hdr->_nexth = ipr->nexth;
|
|
frag_hdr->reserved = 0;
|
|
frag_hdr->_fragment_offset = 0;
|
|
frag_hdr->_identification = 0;
|
|
|
|
/* release the sources allocate for the fragment queue entry */
|
|
if (reassdatagrams == ipr) {
|
|
/* it was the first in the list */
|
|
reassdatagrams = ipr->next;
|
|
} else {
|
|
/* it wasn't the first, so it must have a valid 'prev' */
|
|
LWIP_ASSERT("sanity check linked list", ipr_prev != NULL);
|
|
ipr_prev->next = ipr->next;
|
|
}
|
|
memp_free(MEMP_IP6_REASSDATA, ipr);
|
|
|
|
/* adjust the number of pbufs currently queued for reassembly. */
|
|
ip6_reass_pbufcount -= pbuf_clen(p);
|
|
|
|
/* Move pbuf back to IPv6 header. */
|
|
if (pbuf_header(p, (u8_t*)p->payload - (u8_t*)ipr->iphdr)) {
|
|
LWIP_ASSERT("ip6_reass: moving p->payload to ip6 header failed\n", 0);
|
|
pbuf_free(p);
|
|
return NULL;
|
|
}
|
|
|
|
/* Return the pbuf chain */
|
|
return p;
|
|
}
|
|
/* the datagram is not (yet?) reassembled completely */
|
|
return NULL;
|
|
|
|
nullreturn:
|
|
pbuf_free(p);
|
|
return NULL;
|
|
}
|
|
|
|
#endif /* LWIP_IPV6 ^^ LWIP_IPV6_REASS */
|
|
|
|
#if LWIP_IPV6 && LWIP_IPV6_FRAG
|
|
|
|
/** Allocate a new struct pbuf_custom_ref */
|
|
static struct pbuf_custom_ref*
|
|
ip6_frag_alloc_pbuf_custom_ref(void)
|
|
{
|
|
return (struct pbuf_custom_ref*)memp_malloc(MEMP_FRAG_PBUF);
|
|
}
|
|
|
|
/** Free a struct pbuf_custom_ref */
|
|
static void
|
|
ip6_frag_free_pbuf_custom_ref(struct pbuf_custom_ref* p)
|
|
{
|
|
LWIP_ASSERT("p != NULL", p != NULL);
|
|
memp_free(MEMP_FRAG_PBUF, p);
|
|
}
|
|
|
|
/** Free-callback function to free a 'struct pbuf_custom_ref', called by
|
|
* pbuf_free. */
|
|
static void
|
|
ip6_frag_free_pbuf_custom(struct pbuf *p)
|
|
{
|
|
struct pbuf_custom_ref *pcr = (struct pbuf_custom_ref*)p;
|
|
LWIP_ASSERT("pcr != NULL", pcr != NULL);
|
|
LWIP_ASSERT("pcr == p", (void*)pcr == (void*)p);
|
|
if (pcr->original != NULL) {
|
|
pbuf_free(pcr->original);
|
|
}
|
|
ip6_frag_free_pbuf_custom_ref(pcr);
|
|
}
|
|
|
|
/**
|
|
* Fragment an IPv6 datagram if too large for the netif or path MTU.
|
|
*
|
|
* Chop the datagram in MTU sized chunks and send them in order
|
|
* by pointing PBUF_REFs into p
|
|
*
|
|
* @param p ipv6 packet to send
|
|
* @param netif the netif on which to send
|
|
* @param dest destination ipv6 address to which to send
|
|
*
|
|
* @return ERR_OK if sent successfully, err_t otherwise
|
|
*/
|
|
err_t
|
|
ip6_frag(struct pbuf *p, struct netif *netif, ip6_addr_t *dest)
|
|
{
|
|
struct ip6_hdr *original_ip6hdr;
|
|
struct ip6_hdr *ip6hdr;
|
|
struct ip6_frag_hdr * frag_hdr;
|
|
struct pbuf *rambuf;
|
|
struct pbuf *newpbuf;
|
|
static u32_t identification;
|
|
u16_t nfb;
|
|
u16_t left, cop;
|
|
u16_t mtu;
|
|
u16_t fragment_offset = 0;
|
|
u16_t last;
|
|
u16_t poff = IP6_HLEN;
|
|
u16_t newpbuflen = 0;
|
|
u16_t left_to_copy;
|
|
|
|
identification++;
|
|
|
|
original_ip6hdr = (struct ip6_hdr *)p->payload;
|
|
|
|
mtu = nd6_get_destination_mtu(dest, netif);
|
|
|
|
/* TODO we assume there are no options in the unfragmentable part (IPv6 header). */
|
|
left = p->tot_len - IP6_HLEN;
|
|
|
|
nfb = (mtu - (IP6_HLEN + IP6_FRAG_HLEN)) & IP6_FRAG_OFFSET_MASK;
|
|
|
|
while (left) {
|
|
last = (left <= nfb);
|
|
|
|
/* Fill this fragment */
|
|
cop = last ? left : nfb;
|
|
|
|
/* When not using a static buffer, create a chain of pbufs.
|
|
* The first will be a PBUF_RAM holding the link, IPv6, and Fragment header.
|
|
* The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
|
|
* but limited to the size of an mtu.
|
|
*/
|
|
rambuf = pbuf_alloc(PBUF_LINK, IP6_HLEN + IP6_FRAG_HLEN, PBUF_RAM);
|
|
if (rambuf == NULL) {
|
|
IP6_FRAG_STATS_INC(ip6_frag.memerr);
|
|
return ERR_MEM;
|
|
}
|
|
LWIP_ASSERT("this needs a pbuf in one piece!",
|
|
(p->len >= (IP6_HLEN + IP6_FRAG_HLEN)));
|
|
SMEMCPY(rambuf->payload, original_ip6hdr, IP6_HLEN);
|
|
ip6hdr = (struct ip6_hdr *)rambuf->payload;
|
|
frag_hdr = (struct ip6_frag_hdr *)((u8_t*)rambuf->payload + IP6_HLEN);
|
|
|
|
/* Can just adjust p directly for needed offset. */
|
|
p->payload = (u8_t *)p->payload + poff;
|
|
p->len -= poff;
|
|
p->tot_len -= poff;
|
|
|
|
left_to_copy = cop;
|
|
while (left_to_copy) {
|
|
struct pbuf_custom_ref *pcr;
|
|
newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
|
|
/* Is this pbuf already empty? */
|
|
if (!newpbuflen) {
|
|
p = p->next;
|
|
continue;
|
|
}
|
|
pcr = ip6_frag_alloc_pbuf_custom_ref();
|
|
if (pcr == NULL) {
|
|
pbuf_free(rambuf);
|
|
IP6_FRAG_STATS_INC(ip6_frag.memerr);
|
|
return ERR_MEM;
|
|
}
|
|
/* Mirror this pbuf, although we might not need all of it. */
|
|
newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
|
|
if (newpbuf == NULL) {
|
|
ip6_frag_free_pbuf_custom_ref(pcr);
|
|
pbuf_free(rambuf);
|
|
IP6_FRAG_STATS_INC(ip6_frag.memerr);
|
|
return ERR_MEM;
|
|
}
|
|
pbuf_ref(p);
|
|
pcr->original = p;
|
|
pcr->pc.custom_free_function = ip6_frag_free_pbuf_custom;
|
|
|
|
/* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
|
|
* so that it is removed when pbuf_dechain is later called on rambuf.
|
|
*/
|
|
pbuf_cat(rambuf, newpbuf);
|
|
left_to_copy -= newpbuflen;
|
|
if (left_to_copy) {
|
|
p = p->next;
|
|
}
|
|
}
|
|
poff = newpbuflen;
|
|
|
|
/* Set headers */
|
|
frag_hdr->_nexth = original_ip6hdr->_nexth;
|
|
frag_hdr->reserved = 0;
|
|
frag_hdr->_fragment_offset = htons((fragment_offset & IP6_FRAG_OFFSET_MASK) | (last ? 0 : IP6_FRAG_MORE_FLAG));
|
|
frag_hdr->_identification = htonl(identification);
|
|
|
|
IP6H_NEXTH_SET(ip6hdr, IP6_NEXTH_FRAGMENT);
|
|
IP6H_PLEN_SET(ip6hdr, cop + IP6_FRAG_HLEN);
|
|
|
|
/* No need for separate header pbuf - we allowed room for it in rambuf
|
|
* when allocated.
|
|
*/
|
|
IP6_FRAG_STATS_INC(ip6_frag.xmit);
|
|
netif->output_ip6(netif, rambuf, dest);
|
|
|
|
/* Unfortunately we can't reuse rambuf - the hardware may still be
|
|
* using the buffer. Instead we free it (and the ensuing chain) and
|
|
* recreate it next time round the loop. If we're lucky the hardware
|
|
* will have already sent the packet, the free will really free, and
|
|
* there will be zero memory penalty.
|
|
*/
|
|
|
|
pbuf_free(rambuf);
|
|
left -= cop;
|
|
fragment_offset += cop;
|
|
}
|
|
return ERR_OK;
|
|
}
|
|
|
|
#endif /* LWIP_IPV6 && LWIP_IPV6_FRAG */
|