Yasushi TAUCHI / Mbed 2 deprecated giken9_HTMLServer_Sample

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Dependencies:   EthernetInterface HttpServer TextLCD mbed-rpc mbed-rtos mbed Socket lwip-eth lwip-sys lwip

EthernetInterface/lwip/core/ipv4/ip_frag.c@0:7766f6712673, 2014-03-12 (annotated)

Committer:
yueee_yt
Date:
Wed Mar 12 04:19:54 2014 +0000
Revision:
0:7766f6712673
???????????????

Who changed what in which revision?

UserRevisionLine numberNew contents of line
yueee_yt 0:7766f6712673 1 /**
yueee_yt 0:7766f6712673 2 * @file
yueee_yt 0:7766f6712673 3 * This is the IPv4 packet segmentation and reassembly implementation.
yueee_yt 0:7766f6712673 4 *
yueee_yt 0:7766f6712673 5 */
yueee_yt 0:7766f6712673 6
yueee_yt 0:7766f6712673 7 /*
yueee_yt 0:7766f6712673 8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
yueee_yt 0:7766f6712673 9 * All rights reserved.
yueee_yt 0:7766f6712673 10 *
yueee_yt 0:7766f6712673 11 * Redistribution and use in source and binary forms, with or without modification,
yueee_yt 0:7766f6712673 12 * are permitted provided that the following conditions are met:
yueee_yt 0:7766f6712673 13 *
yueee_yt 0:7766f6712673 14 * 1. Redistributions of source code must retain the above copyright notice,
yueee_yt 0:7766f6712673 15 * this list of conditions and the following disclaimer.
yueee_yt 0:7766f6712673 16 * 2. Redistributions in binary form must reproduce the above copyright notice,
yueee_yt 0:7766f6712673 17 * this list of conditions and the following disclaimer in the documentation
yueee_yt 0:7766f6712673 18 * and/or other materials provided with the distribution.
yueee_yt 0:7766f6712673 19 * 3. The name of the author may not be used to endorse or promote products
yueee_yt 0:7766f6712673 20 * derived from this software without specific prior written permission.
yueee_yt 0:7766f6712673 21 *
yueee_yt 0:7766f6712673 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
yueee_yt 0:7766f6712673 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
yueee_yt 0:7766f6712673 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
yueee_yt 0:7766f6712673 25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
yueee_yt 0:7766f6712673 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
yueee_yt 0:7766f6712673 27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
yueee_yt 0:7766f6712673 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
yueee_yt 0:7766f6712673 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
yueee_yt 0:7766f6712673 30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
yueee_yt 0:7766f6712673 31 * OF SUCH DAMAGE.
yueee_yt 0:7766f6712673 32 *
yueee_yt 0:7766f6712673 33 * This file is part of the lwIP TCP/IP stack.
yueee_yt 0:7766f6712673 34 *
yueee_yt 0:7766f6712673 35 * Author: Jani Monoses <jani@iv.ro>
yueee_yt 0:7766f6712673 36 * Simon Goldschmidt
yueee_yt 0:7766f6712673 37 * original reassembly code by Adam Dunkels <adam@sics.se>
yueee_yt 0:7766f6712673 38 *
yueee_yt 0:7766f6712673 39 */
yueee_yt 0:7766f6712673 40
yueee_yt 0:7766f6712673 41 #include "lwip/opt.h"
yueee_yt 0:7766f6712673 42 #include "lwip/ip_frag.h"
yueee_yt 0:7766f6712673 43 #include "lwip/def.h"
yueee_yt 0:7766f6712673 44 #include "lwip/inet_chksum.h"
yueee_yt 0:7766f6712673 45 #include "lwip/netif.h"
yueee_yt 0:7766f6712673 46 #include "lwip/snmp.h"
yueee_yt 0:7766f6712673 47 #include "lwip/stats.h"
yueee_yt 0:7766f6712673 48 #include "lwip/icmp.h"
yueee_yt 0:7766f6712673 49
yueee_yt 0:7766f6712673 50 #include <string.h>
yueee_yt 0:7766f6712673 51
yueee_yt 0:7766f6712673 52 #if IP_REASSEMBLY
yueee_yt 0:7766f6712673 53 /**
yueee_yt 0:7766f6712673 54 * The IP reassembly code currently has the following limitations:
yueee_yt 0:7766f6712673 55 * - IP header options are not supported
yueee_yt 0:7766f6712673 56 * - fragments must not overlap (e.g. due to different routes),
yueee_yt 0:7766f6712673 57 * currently, overlapping or duplicate fragments are thrown away
yueee_yt 0:7766f6712673 58 * if IP_REASS_CHECK_OVERLAP=1 (the default)!
yueee_yt 0:7766f6712673 59 *
yueee_yt 0:7766f6712673 60 * @todo: work with IP header options
yueee_yt 0:7766f6712673 61 */
yueee_yt 0:7766f6712673 62
yueee_yt 0:7766f6712673 63 /** Setting this to 0, you can turn off checking the fragments for overlapping
yueee_yt 0:7766f6712673 64 * regions. The code gets a little smaller. Only use this if you know that
yueee_yt 0:7766f6712673 65 * overlapping won't occur on your network! */
yueee_yt 0:7766f6712673 66 #ifndef IP_REASS_CHECK_OVERLAP
yueee_yt 0:7766f6712673 67 #define IP_REASS_CHECK_OVERLAP 1
yueee_yt 0:7766f6712673 68 #endif /* IP_REASS_CHECK_OVERLAP */
yueee_yt 0:7766f6712673 69
yueee_yt 0:7766f6712673 70 /** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
yueee_yt 0:7766f6712673 71 * full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
yueee_yt 0:7766f6712673 72 * Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
yueee_yt 0:7766f6712673 73 * is set to 1, so one datagram can be reassembled at a time, only. */
yueee_yt 0:7766f6712673 74 #ifndef IP_REASS_FREE_OLDEST
yueee_yt 0:7766f6712673 75 #define IP_REASS_FREE_OLDEST 1
yueee_yt 0:7766f6712673 76 #endif /* IP_REASS_FREE_OLDEST */
yueee_yt 0:7766f6712673 77
yueee_yt 0:7766f6712673 78 #define IP_REASS_FLAG_LASTFRAG 0x01
yueee_yt 0:7766f6712673 79
yueee_yt 0:7766f6712673 80 /** This is a helper struct which holds the starting
yueee_yt 0:7766f6712673 81 * offset and the ending offset of this fragment to
yueee_yt 0:7766f6712673 82 * easily chain the fragments.
yueee_yt 0:7766f6712673 83 * It has the same packing requirements as the IP header, since it replaces
yueee_yt 0:7766f6712673 84 * the IP header in memory in incoming fragments (after copying it) to keep
yueee_yt 0:7766f6712673 85 * track of the various fragments. (-> If the IP header doesn't need packing,
yueee_yt 0:7766f6712673 86 * this struct doesn't need packing, too.)
yueee_yt 0:7766f6712673 87 */
yueee_yt 0:7766f6712673 88 #ifdef PACK_STRUCT_USE_INCLUDES
yueee_yt 0:7766f6712673 89 # include "arch/bpstruct.h"
yueee_yt 0:7766f6712673 90 #endif
yueee_yt 0:7766f6712673 91 PACK_STRUCT_BEGIN
yueee_yt 0:7766f6712673 92 struct ip_reass_helper {
yueee_yt 0:7766f6712673 93 PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
yueee_yt 0:7766f6712673 94 PACK_STRUCT_FIELD(u16_t start);
yueee_yt 0:7766f6712673 95 PACK_STRUCT_FIELD(u16_t end);
yueee_yt 0:7766f6712673 96 } PACK_STRUCT_STRUCT;
yueee_yt 0:7766f6712673 97 PACK_STRUCT_END
yueee_yt 0:7766f6712673 98 #ifdef PACK_STRUCT_USE_INCLUDES
yueee_yt 0:7766f6712673 99 # include "arch/epstruct.h"
yueee_yt 0:7766f6712673 100 #endif
yueee_yt 0:7766f6712673 101
yueee_yt 0:7766f6712673 102 #define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB) \
yueee_yt 0:7766f6712673 103 (ip_addr_cmp(&(iphdrA)->src, &(iphdrB)->src) && \
yueee_yt 0:7766f6712673 104 ip_addr_cmp(&(iphdrA)->dest, &(iphdrB)->dest) && \
yueee_yt 0:7766f6712673 105 IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0
yueee_yt 0:7766f6712673 106
yueee_yt 0:7766f6712673 107 /* global variables */
yueee_yt 0:7766f6712673 108 static struct ip_reassdata *reassdatagrams;
yueee_yt 0:7766f6712673 109 static u16_t ip_reass_pbufcount;
yueee_yt 0:7766f6712673 110
yueee_yt 0:7766f6712673 111 /* function prototypes */
yueee_yt 0:7766f6712673 112 static void ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
yueee_yt 0:7766f6712673 113 static int ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
yueee_yt 0:7766f6712673 114
yueee_yt 0:7766f6712673 115 /**
yueee_yt 0:7766f6712673 116 * Reassembly timer base function
yueee_yt 0:7766f6712673 117 * for both NO_SYS == 0 and 1 (!).
yueee_yt 0:7766f6712673 118 *
yueee_yt 0:7766f6712673 119 * Should be called every 1000 msec (defined by IP_TMR_INTERVAL).
yueee_yt 0:7766f6712673 120 */
yueee_yt 0:7766f6712673 121 void
yueee_yt 0:7766f6712673 122 ip_reass_tmr(void)
yueee_yt 0:7766f6712673 123 {
yueee_yt 0:7766f6712673 124 struct ip_reassdata *r, *prev = NULL;
yueee_yt 0:7766f6712673 125
yueee_yt 0:7766f6712673 126 r = reassdatagrams;
yueee_yt 0:7766f6712673 127 while (r != NULL) {
yueee_yt 0:7766f6712673 128 /* Decrement the timer. Once it reaches 0,
yueee_yt 0:7766f6712673 129 * clean up the incomplete fragment assembly */
yueee_yt 0:7766f6712673 130 if (r->timer > 0) {
yueee_yt 0:7766f6712673 131 r->timer--;
yueee_yt 0:7766f6712673 132 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)r->timer));
yueee_yt 0:7766f6712673 133 prev = r;
yueee_yt 0:7766f6712673 134 r = r->next;
yueee_yt 0:7766f6712673 135 } else {
yueee_yt 0:7766f6712673 136 /* reassembly timed out */
yueee_yt 0:7766f6712673 137 struct ip_reassdata *tmp;
yueee_yt 0:7766f6712673 138 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out\n"));
yueee_yt 0:7766f6712673 139 tmp = r;
yueee_yt 0:7766f6712673 140 /* get the next pointer before freeing */
yueee_yt 0:7766f6712673 141 r = r->next;
yueee_yt 0:7766f6712673 142 /* free the helper struct and all enqueued pbufs */
yueee_yt 0:7766f6712673 143 ip_reass_free_complete_datagram(tmp, prev);
yueee_yt 0:7766f6712673 144 }
yueee_yt 0:7766f6712673 145 }
yueee_yt 0:7766f6712673 146 }
yueee_yt 0:7766f6712673 147
yueee_yt 0:7766f6712673 148 /**
yueee_yt 0:7766f6712673 149 * Free a datagram (struct ip_reassdata) and all its pbufs.
yueee_yt 0:7766f6712673 150 * Updates the total count of enqueued pbufs (ip_reass_pbufcount),
yueee_yt 0:7766f6712673 151 * SNMP counters and sends an ICMP time exceeded packet.
yueee_yt 0:7766f6712673 152 *
yueee_yt 0:7766f6712673 153 * @param ipr datagram to free
yueee_yt 0:7766f6712673 154 * @param prev the previous datagram in the linked list
yueee_yt 0:7766f6712673 155 * @return the number of pbufs freed
yueee_yt 0:7766f6712673 156 */
yueee_yt 0:7766f6712673 157 static int
yueee_yt 0:7766f6712673 158 ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
yueee_yt 0:7766f6712673 159 {
yueee_yt 0:7766f6712673 160 u16_t pbufs_freed = 0;
yueee_yt 0:7766f6712673 161 u8_t clen;
yueee_yt 0:7766f6712673 162 struct pbuf *p;
yueee_yt 0:7766f6712673 163 struct ip_reass_helper *iprh;
yueee_yt 0:7766f6712673 164
yueee_yt 0:7766f6712673 165 LWIP_ASSERT("prev != ipr", prev != ipr);
yueee_yt 0:7766f6712673 166 if (prev != NULL) {
yueee_yt 0:7766f6712673 167 LWIP_ASSERT("prev->next == ipr", prev->next == ipr);
yueee_yt 0:7766f6712673 168 }
yueee_yt 0:7766f6712673 169
yueee_yt 0:7766f6712673 170 snmp_inc_ipreasmfails();
yueee_yt 0:7766f6712673 171 #if LWIP_ICMP
yueee_yt 0:7766f6712673 172 iprh = (struct ip_reass_helper *)ipr->p->payload;
yueee_yt 0:7766f6712673 173 if (iprh->start == 0) {
yueee_yt 0:7766f6712673 174 /* The first fragment was received, send ICMP time exceeded. */
yueee_yt 0:7766f6712673 175 /* First, de-queue the first pbuf from r->p. */
yueee_yt 0:7766f6712673 176 p = ipr->p;
yueee_yt 0:7766f6712673 177 ipr->p = iprh->next_pbuf;
yueee_yt 0:7766f6712673 178 /* Then, copy the original header into it. */
yueee_yt 0:7766f6712673 179 SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN);
yueee_yt 0:7766f6712673 180 icmp_time_exceeded(p, ICMP_TE_FRAG);
yueee_yt 0:7766f6712673 181 clen = pbuf_clen(p);
yueee_yt 0:7766f6712673 182 LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
yueee_yt 0:7766f6712673 183 pbufs_freed += clen;
yueee_yt 0:7766f6712673 184 pbuf_free(p);
yueee_yt 0:7766f6712673 185 }
yueee_yt 0:7766f6712673 186 #endif /* LWIP_ICMP */
yueee_yt 0:7766f6712673 187
yueee_yt 0:7766f6712673 188 /* First, free all received pbufs. The individual pbufs need to be released
yueee_yt 0:7766f6712673 189 separately as they have not yet been chained */
yueee_yt 0:7766f6712673 190 p = ipr->p;
yueee_yt 0:7766f6712673 191 while (p != NULL) {
yueee_yt 0:7766f6712673 192 struct pbuf *pcur;
yueee_yt 0:7766f6712673 193 iprh = (struct ip_reass_helper *)p->payload;
yueee_yt 0:7766f6712673 194 pcur = p;
yueee_yt 0:7766f6712673 195 /* get the next pointer before freeing */
yueee_yt 0:7766f6712673 196 p = iprh->next_pbuf;
yueee_yt 0:7766f6712673 197 clen = pbuf_clen(pcur);
yueee_yt 0:7766f6712673 198 LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
yueee_yt 0:7766f6712673 199 pbufs_freed += clen;
yueee_yt 0:7766f6712673 200 pbuf_free(pcur);
yueee_yt 0:7766f6712673 201 }
yueee_yt 0:7766f6712673 202 /* Then, unchain the struct ip_reassdata from the list and free it. */
yueee_yt 0:7766f6712673 203 ip_reass_dequeue_datagram(ipr, prev);
yueee_yt 0:7766f6712673 204 LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= pbufs_freed);
yueee_yt 0:7766f6712673 205 ip_reass_pbufcount -= pbufs_freed;
yueee_yt 0:7766f6712673 206
yueee_yt 0:7766f6712673 207 return pbufs_freed;
yueee_yt 0:7766f6712673 208 }
yueee_yt 0:7766f6712673 209
yueee_yt 0:7766f6712673 210 #if IP_REASS_FREE_OLDEST
yueee_yt 0:7766f6712673 211 /**
yueee_yt 0:7766f6712673 212 * Free the oldest datagram to make room for enqueueing new fragments.
yueee_yt 0:7766f6712673 213 * The datagram 'fraghdr' belongs to is not freed!
yueee_yt 0:7766f6712673 214 *
yueee_yt 0:7766f6712673 215 * @param fraghdr IP header of the current fragment
yueee_yt 0:7766f6712673 216 * @param pbufs_needed number of pbufs needed to enqueue
yueee_yt 0:7766f6712673 217 * (used for freeing other datagrams if not enough space)
yueee_yt 0:7766f6712673 218 * @return the number of pbufs freed
yueee_yt 0:7766f6712673 219 */
yueee_yt 0:7766f6712673 220 static int
yueee_yt 0:7766f6712673 221 ip_reass_remove_oldest_datagram(struct ip_hdr *fraghdr, int pbufs_needed)
yueee_yt 0:7766f6712673 222 {
yueee_yt 0:7766f6712673 223 /* @todo Can't we simply remove the last datagram in the
yueee_yt 0:7766f6712673 224 * linked list behind reassdatagrams?
yueee_yt 0:7766f6712673 225 */
yueee_yt 0:7766f6712673 226 struct ip_reassdata *r, *oldest, *prev;
yueee_yt 0:7766f6712673 227 int pbufs_freed = 0, pbufs_freed_current;
yueee_yt 0:7766f6712673 228 int other_datagrams;
yueee_yt 0:7766f6712673 229
yueee_yt 0:7766f6712673 230 /* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
yueee_yt 0:7766f6712673 231 * but don't free the datagram that 'fraghdr' belongs to! */
yueee_yt 0:7766f6712673 232 do {
yueee_yt 0:7766f6712673 233 oldest = NULL;
yueee_yt 0:7766f6712673 234 prev = NULL;
yueee_yt 0:7766f6712673 235 other_datagrams = 0;
yueee_yt 0:7766f6712673 236 r = reassdatagrams;
yueee_yt 0:7766f6712673 237 while (r != NULL) {
yueee_yt 0:7766f6712673 238 if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) {
yueee_yt 0:7766f6712673 239 /* Not the same datagram as fraghdr */
yueee_yt 0:7766f6712673 240 other_datagrams++;
yueee_yt 0:7766f6712673 241 if (oldest == NULL) {
yueee_yt 0:7766f6712673 242 oldest = r;
yueee_yt 0:7766f6712673 243 } else if (r->timer <= oldest->timer) {
yueee_yt 0:7766f6712673 244 /* older than the previous oldest */
yueee_yt 0:7766f6712673 245 oldest = r;
yueee_yt 0:7766f6712673 246 }
yueee_yt 0:7766f6712673 247 }
yueee_yt 0:7766f6712673 248 if (r->next != NULL) {
yueee_yt 0:7766f6712673 249 prev = r;
yueee_yt 0:7766f6712673 250 }
yueee_yt 0:7766f6712673 251 r = r->next;
yueee_yt 0:7766f6712673 252 }
yueee_yt 0:7766f6712673 253 if (oldest != NULL) {
yueee_yt 0:7766f6712673 254 pbufs_freed_current = ip_reass_free_complete_datagram(oldest, prev);
yueee_yt 0:7766f6712673 255 pbufs_freed += pbufs_freed_current;
yueee_yt 0:7766f6712673 256 }
yueee_yt 0:7766f6712673 257 } while ((pbufs_freed < pbufs_needed) && (other_datagrams > 1));
yueee_yt 0:7766f6712673 258 return pbufs_freed;
yueee_yt 0:7766f6712673 259 }
yueee_yt 0:7766f6712673 260 #endif /* IP_REASS_FREE_OLDEST */
yueee_yt 0:7766f6712673 261
yueee_yt 0:7766f6712673 262 /**
yueee_yt 0:7766f6712673 263 * Enqueues a new fragment into the fragment queue
yueee_yt 0:7766f6712673 264 * @param fraghdr points to the new fragments IP hdr
yueee_yt 0:7766f6712673 265 * @param clen number of pbufs needed to enqueue (used for freeing other datagrams if not enough space)
yueee_yt 0:7766f6712673 266 * @return A pointer to the queue location into which the fragment was enqueued
yueee_yt 0:7766f6712673 267 */
yueee_yt 0:7766f6712673 268 static struct ip_reassdata*
yueee_yt 0:7766f6712673 269 ip_reass_enqueue_new_datagram(struct ip_hdr *fraghdr, int clen)
yueee_yt 0:7766f6712673 270 {
yueee_yt 0:7766f6712673 271 struct ip_reassdata* ipr;
yueee_yt 0:7766f6712673 272 /* No matching previous fragment found, allocate a new reassdata struct */
yueee_yt 0:7766f6712673 273 ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
yueee_yt 0:7766f6712673 274 if (ipr == NULL) {
yueee_yt 0:7766f6712673 275 #if IP_REASS_FREE_OLDEST
yueee_yt 0:7766f6712673 276 if (ip_reass_remove_oldest_datagram(fraghdr, clen) >= clen) {
yueee_yt 0:7766f6712673 277 ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
yueee_yt 0:7766f6712673 278 }
yueee_yt 0:7766f6712673 279 if (ipr == NULL)
yueee_yt 0:7766f6712673 280 #endif /* IP_REASS_FREE_OLDEST */
yueee_yt 0:7766f6712673 281 {
yueee_yt 0:7766f6712673 282 IPFRAG_STATS_INC(ip_frag.memerr);
yueee_yt 0:7766f6712673 283 LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct\n"));
yueee_yt 0:7766f6712673 284 return NULL;
yueee_yt 0:7766f6712673 285 }
yueee_yt 0:7766f6712673 286 }
yueee_yt 0:7766f6712673 287 memset(ipr, 0, sizeof(struct ip_reassdata));
yueee_yt 0:7766f6712673 288 ipr->timer = IP_REASS_MAXAGE;
yueee_yt 0:7766f6712673 289
yueee_yt 0:7766f6712673 290 /* enqueue the new structure to the front of the list */
yueee_yt 0:7766f6712673 291 ipr->next = reassdatagrams;
yueee_yt 0:7766f6712673 292 reassdatagrams = ipr;
yueee_yt 0:7766f6712673 293 /* copy the ip header for later tests and input */
yueee_yt 0:7766f6712673 294 /* @todo: no ip options supported? */
yueee_yt 0:7766f6712673 295 SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN);
yueee_yt 0:7766f6712673 296 return ipr;
yueee_yt 0:7766f6712673 297 }
yueee_yt 0:7766f6712673 298
yueee_yt 0:7766f6712673 299 /**
yueee_yt 0:7766f6712673 300 * Dequeues a datagram from the datagram queue. Doesn't deallocate the pbufs.
yueee_yt 0:7766f6712673 301 * @param ipr points to the queue entry to dequeue
yueee_yt 0:7766f6712673 302 */
yueee_yt 0:7766f6712673 303 static void
yueee_yt 0:7766f6712673 304 ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
yueee_yt 0:7766f6712673 305 {
yueee_yt 0:7766f6712673 306
yueee_yt 0:7766f6712673 307 /* dequeue the reass struct */
yueee_yt 0:7766f6712673 308 if (reassdatagrams == ipr) {
yueee_yt 0:7766f6712673 309 /* it was the first in the list */
yueee_yt 0:7766f6712673 310 reassdatagrams = ipr->next;
yueee_yt 0:7766f6712673 311 } else {
yueee_yt 0:7766f6712673 312 /* it wasn't the first, so it must have a valid 'prev' */
yueee_yt 0:7766f6712673 313 LWIP_ASSERT("sanity check linked list", prev != NULL);
yueee_yt 0:7766f6712673 314 prev->next = ipr->next;
yueee_yt 0:7766f6712673 315 }
yueee_yt 0:7766f6712673 316
yueee_yt 0:7766f6712673 317 /* now we can free the ip_reass struct */
yueee_yt 0:7766f6712673 318 memp_free(MEMP_REASSDATA, ipr);
yueee_yt 0:7766f6712673 319 }
yueee_yt 0:7766f6712673 320
yueee_yt 0:7766f6712673 321 /**
yueee_yt 0:7766f6712673 322 * Chain a new pbuf into the pbuf list that composes the datagram. The pbuf list
yueee_yt 0:7766f6712673 323 * will grow over time as new pbufs are rx.
yueee_yt 0:7766f6712673 324 * Also checks that the datagram passes basic continuity checks (if the last
yueee_yt 0:7766f6712673 325 * fragment was received at least once).
yueee_yt 0:7766f6712673 326 * @param root_p points to the 'root' pbuf for the current datagram being assembled.
yueee_yt 0:7766f6712673 327 * @param new_p points to the pbuf for the current fragment
yueee_yt 0:7766f6712673 328 * @return 0 if invalid, >0 otherwise
yueee_yt 0:7766f6712673 329 */
yueee_yt 0:7766f6712673 330 static int
yueee_yt 0:7766f6712673 331 ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata *ipr, struct pbuf *new_p)
yueee_yt 0:7766f6712673 332 {
yueee_yt 0:7766f6712673 333 struct ip_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
yueee_yt 0:7766f6712673 334 struct pbuf *q;
yueee_yt 0:7766f6712673 335 u16_t offset,len;
yueee_yt 0:7766f6712673 336 struct ip_hdr *fraghdr;
yueee_yt 0:7766f6712673 337 int valid = 1;
yueee_yt 0:7766f6712673 338
yueee_yt 0:7766f6712673 339 /* Extract length and fragment offset from current fragment */
yueee_yt 0:7766f6712673 340 fraghdr = (struct ip_hdr*)new_p->payload;
yueee_yt 0:7766f6712673 341 len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
yueee_yt 0:7766f6712673 342 offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
yueee_yt 0:7766f6712673 343
yueee_yt 0:7766f6712673 344 /* overwrite the fragment's ip header from the pbuf with our helper struct,
yueee_yt 0:7766f6712673 345 * and setup the embedded helper structure. */
yueee_yt 0:7766f6712673 346 /* make sure the struct ip_reass_helper fits into the IP header */
yueee_yt 0:7766f6712673 347 LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN",
yueee_yt 0:7766f6712673 348 sizeof(struct ip_reass_helper) <= IP_HLEN);
yueee_yt 0:7766f6712673 349 iprh = (struct ip_reass_helper*)new_p->payload;
yueee_yt 0:7766f6712673 350 iprh->next_pbuf = NULL;
yueee_yt 0:7766f6712673 351 iprh->start = offset;
yueee_yt 0:7766f6712673 352 iprh->end = offset + len;
yueee_yt 0:7766f6712673 353
yueee_yt 0:7766f6712673 354 /* Iterate through until we either get to the end of the list (append),
yueee_yt 0:7766f6712673 355 * or we find on with a larger offset (insert). */
yueee_yt 0:7766f6712673 356 for (q = ipr->p; q != NULL;) {
yueee_yt 0:7766f6712673 357 iprh_tmp = (struct ip_reass_helper*)q->payload;
yueee_yt 0:7766f6712673 358 if (iprh->start < iprh_tmp->start) {
yueee_yt 0:7766f6712673 359 /* the new pbuf should be inserted before this */
yueee_yt 0:7766f6712673 360 iprh->next_pbuf = q;
yueee_yt 0:7766f6712673 361 if (iprh_prev != NULL) {
yueee_yt 0:7766f6712673 362 /* not the fragment with the lowest offset */
yueee_yt 0:7766f6712673 363 #if IP_REASS_CHECK_OVERLAP
yueee_yt 0:7766f6712673 364 if ((iprh->start < iprh_prev->end) || (iprh->end > iprh_tmp->start)) {
yueee_yt 0:7766f6712673 365 /* fragment overlaps with previous or following, throw away */
yueee_yt 0:7766f6712673 366 goto freepbuf;
yueee_yt 0:7766f6712673 367 }
yueee_yt 0:7766f6712673 368 #endif /* IP_REASS_CHECK_OVERLAP */
yueee_yt 0:7766f6712673 369 iprh_prev->next_pbuf = new_p;
yueee_yt 0:7766f6712673 370 } else {
yueee_yt 0:7766f6712673 371 /* fragment with the lowest offset */
yueee_yt 0:7766f6712673 372 ipr->p = new_p;
yueee_yt 0:7766f6712673 373 }
yueee_yt 0:7766f6712673 374 break;
yueee_yt 0:7766f6712673 375 } else if(iprh->start == iprh_tmp->start) {
yueee_yt 0:7766f6712673 376 /* received the same datagram twice: no need to keep the datagram */
yueee_yt 0:7766f6712673 377 goto freepbuf;
yueee_yt 0:7766f6712673 378 #if IP_REASS_CHECK_OVERLAP
yueee_yt 0:7766f6712673 379 } else if(iprh->start < iprh_tmp->end) {
yueee_yt 0:7766f6712673 380 /* overlap: no need to keep the new datagram */
yueee_yt 0:7766f6712673 381 goto freepbuf;
yueee_yt 0:7766f6712673 382 #endif /* IP_REASS_CHECK_OVERLAP */
yueee_yt 0:7766f6712673 383 } else {
yueee_yt 0:7766f6712673 384 /* Check if the fragments received so far have no wholes. */
yueee_yt 0:7766f6712673 385 if (iprh_prev != NULL) {
yueee_yt 0:7766f6712673 386 if (iprh_prev->end != iprh_tmp->start) {
yueee_yt 0:7766f6712673 387 /* There is a fragment missing between the current
yueee_yt 0:7766f6712673 388 * and the previous fragment */
yueee_yt 0:7766f6712673 389 valid = 0;
yueee_yt 0:7766f6712673 390 }
yueee_yt 0:7766f6712673 391 }
yueee_yt 0:7766f6712673 392 }
yueee_yt 0:7766f6712673 393 q = iprh_tmp->next_pbuf;
yueee_yt 0:7766f6712673 394 iprh_prev = iprh_tmp;
yueee_yt 0:7766f6712673 395 }
yueee_yt 0:7766f6712673 396
yueee_yt 0:7766f6712673 397 /* If q is NULL, then we made it to the end of the list. Determine what to do now */
yueee_yt 0:7766f6712673 398 if (q == NULL) {
yueee_yt 0:7766f6712673 399 if (iprh_prev != NULL) {
yueee_yt 0:7766f6712673 400 /* this is (for now), the fragment with the highest offset:
yueee_yt 0:7766f6712673 401 * chain it to the last fragment */
yueee_yt 0:7766f6712673 402 #if IP_REASS_CHECK_OVERLAP
yueee_yt 0:7766f6712673 403 LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
yueee_yt 0:7766f6712673 404 #endif /* IP_REASS_CHECK_OVERLAP */
yueee_yt 0:7766f6712673 405 iprh_prev->next_pbuf = new_p;
yueee_yt 0:7766f6712673 406 if (iprh_prev->end != iprh->start) {
yueee_yt 0:7766f6712673 407 valid = 0;
yueee_yt 0:7766f6712673 408 }
yueee_yt 0:7766f6712673 409 } else {
yueee_yt 0:7766f6712673 410 #if IP_REASS_CHECK_OVERLAP
yueee_yt 0:7766f6712673 411 LWIP_ASSERT("no previous fragment, this must be the first fragment!",
yueee_yt 0:7766f6712673 412 ipr->p == NULL);
yueee_yt 0:7766f6712673 413 #endif /* IP_REASS_CHECK_OVERLAP */
yueee_yt 0:7766f6712673 414 /* this is the first fragment we ever received for this ip datagram */
yueee_yt 0:7766f6712673 415 ipr->p = new_p;
yueee_yt 0:7766f6712673 416 }
yueee_yt 0:7766f6712673 417 }
yueee_yt 0:7766f6712673 418
yueee_yt 0:7766f6712673 419 /* At this point, the validation part begins: */
yueee_yt 0:7766f6712673 420 /* If we already received the last fragment */
yueee_yt 0:7766f6712673 421 if ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0) {
yueee_yt 0:7766f6712673 422 /* and had no wholes so far */
yueee_yt 0:7766f6712673 423 if (valid) {
yueee_yt 0:7766f6712673 424 /* then check if the rest of the fragments is here */
yueee_yt 0:7766f6712673 425 /* Check if the queue starts with the first datagram */
yueee_yt 0:7766f6712673 426 if (((struct ip_reass_helper*)ipr->p->payload)->start != 0) {
yueee_yt 0:7766f6712673 427 valid = 0;
yueee_yt 0:7766f6712673 428 } else {
yueee_yt 0:7766f6712673 429 /* and check that there are no wholes after this datagram */
yueee_yt 0:7766f6712673 430 iprh_prev = iprh;
yueee_yt 0:7766f6712673 431 q = iprh->next_pbuf;
yueee_yt 0:7766f6712673 432 while (q != NULL) {
yueee_yt 0:7766f6712673 433 iprh = (struct ip_reass_helper*)q->payload;
yueee_yt 0:7766f6712673 434 if (iprh_prev->end != iprh->start) {
yueee_yt 0:7766f6712673 435 valid = 0;
yueee_yt 0:7766f6712673 436 break;
yueee_yt 0:7766f6712673 437 }
yueee_yt 0:7766f6712673 438 iprh_prev = iprh;
yueee_yt 0:7766f6712673 439 q = iprh->next_pbuf;
yueee_yt 0:7766f6712673 440 }
yueee_yt 0:7766f6712673 441 /* if still valid, all fragments are received
yueee_yt 0:7766f6712673 442 * (because to the MF==0 already arrived */
yueee_yt 0:7766f6712673 443 if (valid) {
yueee_yt 0:7766f6712673 444 LWIP_ASSERT("sanity check", ipr->p != NULL);
yueee_yt 0:7766f6712673 445 LWIP_ASSERT("sanity check",
yueee_yt 0:7766f6712673 446 ((struct ip_reass_helper*)ipr->p->payload) != iprh);
yueee_yt 0:7766f6712673 447 LWIP_ASSERT("validate_datagram:next_pbuf!=NULL",
yueee_yt 0:7766f6712673 448 iprh->next_pbuf == NULL);
yueee_yt 0:7766f6712673 449 LWIP_ASSERT("validate_datagram:datagram end!=datagram len",
yueee_yt 0:7766f6712673 450 iprh->end == ipr->datagram_len);
yueee_yt 0:7766f6712673 451 }
yueee_yt 0:7766f6712673 452 }
yueee_yt 0:7766f6712673 453 }
yueee_yt 0:7766f6712673 454 /* If valid is 0 here, there are some fragments missing in the middle
yueee_yt 0:7766f6712673 455 * (since MF == 0 has already arrived). Such datagrams simply time out if
yueee_yt 0:7766f6712673 456 * no more fragments are received... */
yueee_yt 0:7766f6712673 457 return valid;
yueee_yt 0:7766f6712673 458 }
yueee_yt 0:7766f6712673 459 /* If we come here, not all fragments were received, yet! */
yueee_yt 0:7766f6712673 460 return 0; /* not yet valid! */
yueee_yt 0:7766f6712673 461 #if IP_REASS_CHECK_OVERLAP
yueee_yt 0:7766f6712673 462 freepbuf:
yueee_yt 0:7766f6712673 463 ip_reass_pbufcount -= pbuf_clen(new_p);
yueee_yt 0:7766f6712673 464 pbuf_free(new_p);
yueee_yt 0:7766f6712673 465 return 0;
yueee_yt 0:7766f6712673 466 #endif /* IP_REASS_CHECK_OVERLAP */
yueee_yt 0:7766f6712673 467 }
yueee_yt 0:7766f6712673 468
yueee_yt 0:7766f6712673 469 /**
yueee_yt 0:7766f6712673 470 * Reassembles incoming IP fragments into an IP datagram.
yueee_yt 0:7766f6712673 471 *
yueee_yt 0:7766f6712673 472 * @param p points to a pbuf chain of the fragment
yueee_yt 0:7766f6712673 473 * @return NULL if reassembly is incomplete, ? otherwise
yueee_yt 0:7766f6712673 474 */
yueee_yt 0:7766f6712673 475 struct pbuf *
yueee_yt 0:7766f6712673 476 ip_reass(struct pbuf *p)
yueee_yt 0:7766f6712673 477 {
yueee_yt 0:7766f6712673 478 struct pbuf *r;
yueee_yt 0:7766f6712673 479 struct ip_hdr *fraghdr;
yueee_yt 0:7766f6712673 480 struct ip_reassdata *ipr;
yueee_yt 0:7766f6712673 481 struct ip_reass_helper *iprh;
yueee_yt 0:7766f6712673 482 u16_t offset, len;
yueee_yt 0:7766f6712673 483 u8_t clen;
yueee_yt 0:7766f6712673 484 struct ip_reassdata *ipr_prev = NULL;
yueee_yt 0:7766f6712673 485
yueee_yt 0:7766f6712673 486 IPFRAG_STATS_INC(ip_frag.recv);
yueee_yt 0:7766f6712673 487 snmp_inc_ipreasmreqds();
yueee_yt 0:7766f6712673 488
yueee_yt 0:7766f6712673 489 fraghdr = (struct ip_hdr*)p->payload;
yueee_yt 0:7766f6712673 490
yueee_yt 0:7766f6712673 491 if ((IPH_HL(fraghdr) * 4) != IP_HLEN) {
yueee_yt 0:7766f6712673 492 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n"));
yueee_yt 0:7766f6712673 493 IPFRAG_STATS_INC(ip_frag.err);
yueee_yt 0:7766f6712673 494 goto nullreturn;
yueee_yt 0:7766f6712673 495 }
yueee_yt 0:7766f6712673 496
yueee_yt 0:7766f6712673 497 offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
yueee_yt 0:7766f6712673 498 len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
yueee_yt 0:7766f6712673 499
yueee_yt 0:7766f6712673 500 /* Check if we are allowed to enqueue more datagrams. */
yueee_yt 0:7766f6712673 501 clen = pbuf_clen(p);
yueee_yt 0:7766f6712673 502 if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
yueee_yt 0:7766f6712673 503 #if IP_REASS_FREE_OLDEST
yueee_yt 0:7766f6712673 504 if (!ip_reass_remove_oldest_datagram(fraghdr, clen) ||
yueee_yt 0:7766f6712673 505 ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
yueee_yt 0:7766f6712673 506 #endif /* IP_REASS_FREE_OLDEST */
yueee_yt 0:7766f6712673 507 {
yueee_yt 0:7766f6712673 508 /* No datagram could be freed and still too many pbufs enqueued */
yueee_yt 0:7766f6712673 509 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
yueee_yt 0:7766f6712673 510 ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
yueee_yt 0:7766f6712673 511 IPFRAG_STATS_INC(ip_frag.memerr);
yueee_yt 0:7766f6712673 512 /* @todo: send ICMP time exceeded here? */
yueee_yt 0:7766f6712673 513 /* drop this pbuf */
yueee_yt 0:7766f6712673 514 goto nullreturn;
yueee_yt 0:7766f6712673 515 }
yueee_yt 0:7766f6712673 516 }
yueee_yt 0:7766f6712673 517
yueee_yt 0:7766f6712673 518 /* Look for the datagram the fragment belongs to in the current datagram queue,
yueee_yt 0:7766f6712673 519 * remembering the previous in the queue for later dequeueing. */
yueee_yt 0:7766f6712673 520 for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
yueee_yt 0:7766f6712673 521 /* Check if the incoming fragment matches the one currently present
yueee_yt 0:7766f6712673 522 in the reassembly buffer. If so, we proceed with copying the
yueee_yt 0:7766f6712673 523 fragment into the buffer. */
yueee_yt 0:7766f6712673 524 if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
yueee_yt 0:7766f6712673 525 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
yueee_yt 0:7766f6712673 526 ntohs(IPH_ID(fraghdr))));
yueee_yt 0:7766f6712673 527 IPFRAG_STATS_INC(ip_frag.cachehit);
yueee_yt 0:7766f6712673 528 break;
yueee_yt 0:7766f6712673 529 }
yueee_yt 0:7766f6712673 530 ipr_prev = ipr;
yueee_yt 0:7766f6712673 531 }
yueee_yt 0:7766f6712673 532
yueee_yt 0:7766f6712673 533 if (ipr == NULL) {
yueee_yt 0:7766f6712673 534 /* Enqueue a new datagram into the datagram queue */
yueee_yt 0:7766f6712673 535 ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
yueee_yt 0:7766f6712673 536 /* Bail if unable to enqueue */
yueee_yt 0:7766f6712673 537 if(ipr == NULL) {
yueee_yt 0:7766f6712673 538 goto nullreturn;
yueee_yt 0:7766f6712673 539 }
yueee_yt 0:7766f6712673 540 } else {
yueee_yt 0:7766f6712673 541 if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) &&
yueee_yt 0:7766f6712673 542 ((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
yueee_yt 0:7766f6712673 543 /* ipr->iphdr is not the header from the first fragment, but fraghdr is
yueee_yt 0:7766f6712673 544 * -> copy fraghdr into ipr->iphdr since we want to have the header
yueee_yt 0:7766f6712673 545 * of the first fragment (for ICMP time exceeded and later, for copying
yueee_yt 0:7766f6712673 546 * all options, if supported)*/
yueee_yt 0:7766f6712673 547 SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
yueee_yt 0:7766f6712673 548 }
yueee_yt 0:7766f6712673 549 }
yueee_yt 0:7766f6712673 550 /* Track the current number of pbufs current 'in-flight', in order to limit
yueee_yt 0:7766f6712673 551 the number of fragments that may be enqueued at any one time */
yueee_yt 0:7766f6712673 552 ip_reass_pbufcount += clen;
yueee_yt 0:7766f6712673 553
yueee_yt 0:7766f6712673 554 /* At this point, we have either created a new entry or pointing
yueee_yt 0:7766f6712673 555 * to an existing one */
yueee_yt 0:7766f6712673 556
yueee_yt 0:7766f6712673 557 /* check for 'no more fragments', and update queue entry*/
yueee_yt 0:7766f6712673 558 if ((IPH_OFFSET(fraghdr) & PP_NTOHS(IP_MF)) == 0) {
yueee_yt 0:7766f6712673 559 ipr->flags |= IP_REASS_FLAG_LASTFRAG;
yueee_yt 0:7766f6712673 560 ipr->datagram_len = offset + len;
yueee_yt 0:7766f6712673 561 LWIP_DEBUGF(IP_REASS_DEBUG,
yueee_yt 0:7766f6712673 562 ("ip_reass: last fragment seen, total len %"S16_F"\n",
yueee_yt 0:7766f6712673 563 ipr->datagram_len));
yueee_yt 0:7766f6712673 564 }
yueee_yt 0:7766f6712673 565 /* find the right place to insert this pbuf */
yueee_yt 0:7766f6712673 566 /* @todo: trim pbufs if fragments are overlapping */
yueee_yt 0:7766f6712673 567 if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) {
yueee_yt 0:7766f6712673 568 /* the totally last fragment (flag more fragments = 0) was received at least
yueee_yt 0:7766f6712673 569 * once AND all fragments are received */
yueee_yt 0:7766f6712673 570 ipr->datagram_len += IP_HLEN;
yueee_yt 0:7766f6712673 571
yueee_yt 0:7766f6712673 572 /* save the second pbuf before copying the header over the pointer */
yueee_yt 0:7766f6712673 573 r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf;
yueee_yt 0:7766f6712673 574
yueee_yt 0:7766f6712673 575 /* copy the original ip header back to the first pbuf */
yueee_yt 0:7766f6712673 576 fraghdr = (struct ip_hdr*)(ipr->p->payload);
yueee_yt 0:7766f6712673 577 SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
yueee_yt 0:7766f6712673 578 IPH_LEN_SET(fraghdr, htons(ipr->datagram_len));
yueee_yt 0:7766f6712673 579 IPH_OFFSET_SET(fraghdr, 0);
yueee_yt 0:7766f6712673 580 IPH_CHKSUM_SET(fraghdr, 0);
yueee_yt 0:7766f6712673 581 /* @todo: do we need to set calculate the correct checksum? */
yueee_yt 0:7766f6712673 582 IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));
yueee_yt 0:7766f6712673 583
yueee_yt 0:7766f6712673 584 p = ipr->p;
yueee_yt 0:7766f6712673 585
yueee_yt 0:7766f6712673 586 /* chain together the pbufs contained within the reass_data list. */
yueee_yt 0:7766f6712673 587 while(r != NULL) {
yueee_yt 0:7766f6712673 588 iprh = (struct ip_reass_helper*)r->payload;
yueee_yt 0:7766f6712673 589
yueee_yt 0:7766f6712673 590 /* hide the ip header for every succeding fragment */
yueee_yt 0:7766f6712673 591 pbuf_header(r, -IP_HLEN);
yueee_yt 0:7766f6712673 592 pbuf_cat(p, r);
yueee_yt 0:7766f6712673 593 r = iprh->next_pbuf;
yueee_yt 0:7766f6712673 594 }
yueee_yt 0:7766f6712673 595 /* release the sources allocate for the fragment queue entry */
yueee_yt 0:7766f6712673 596 ip_reass_dequeue_datagram(ipr, ipr_prev);
yueee_yt 0:7766f6712673 597
yueee_yt 0:7766f6712673 598 /* and adjust the number of pbufs currently queued for reassembly. */
yueee_yt 0:7766f6712673 599 ip_reass_pbufcount -= pbuf_clen(p);
yueee_yt 0:7766f6712673 600
yueee_yt 0:7766f6712673 601 /* Return the pbuf chain */
yueee_yt 0:7766f6712673 602 return p;
yueee_yt 0:7766f6712673 603 }
yueee_yt 0:7766f6712673 604 /* the datagram is not (yet?) reassembled completely */
yueee_yt 0:7766f6712673 605 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
yueee_yt 0:7766f6712673 606 return NULL;
yueee_yt 0:7766f6712673 607
yueee_yt 0:7766f6712673 608 nullreturn:
yueee_yt 0:7766f6712673 609 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n"));
yueee_yt 0:7766f6712673 610 IPFRAG_STATS_INC(ip_frag.drop);
yueee_yt 0:7766f6712673 611 pbuf_free(p);
yueee_yt 0:7766f6712673 612 return NULL;
yueee_yt 0:7766f6712673 613 }
yueee_yt 0:7766f6712673 614 #endif /* IP_REASSEMBLY */
yueee_yt 0:7766f6712673 615
yueee_yt 0:7766f6712673 616 #if IP_FRAG
yueee_yt 0:7766f6712673 617 #if IP_FRAG_USES_STATIC_BUF
yueee_yt 0:7766f6712673 618 static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU + MEM_ALIGNMENT - 1)];
yueee_yt 0:7766f6712673 619 #else /* IP_FRAG_USES_STATIC_BUF */
yueee_yt 0:7766f6712673 620
yueee_yt 0:7766f6712673 621 #if !LWIP_NETIF_TX_SINGLE_PBUF
yueee_yt 0:7766f6712673 622 /** Allocate a new struct pbuf_custom_ref */
yueee_yt 0:7766f6712673 623 static struct pbuf_custom_ref*
yueee_yt 0:7766f6712673 624 ip_frag_alloc_pbuf_custom_ref(void)
yueee_yt 0:7766f6712673 625 {
yueee_yt 0:7766f6712673 626 return (struct pbuf_custom_ref*)memp_malloc(MEMP_FRAG_PBUF);
yueee_yt 0:7766f6712673 627 }
yueee_yt 0:7766f6712673 628
yueee_yt 0:7766f6712673 629 /** Free a struct pbuf_custom_ref */
yueee_yt 0:7766f6712673 630 static void
yueee_yt 0:7766f6712673 631 ip_frag_free_pbuf_custom_ref(struct pbuf_custom_ref* p)
yueee_yt 0:7766f6712673 632 {
yueee_yt 0:7766f6712673 633 LWIP_ASSERT("p != NULL", p != NULL);
yueee_yt 0:7766f6712673 634 memp_free(MEMP_FRAG_PBUF, p);
yueee_yt 0:7766f6712673 635 }
yueee_yt 0:7766f6712673 636
yueee_yt 0:7766f6712673 637 /** Free-callback function to free a 'struct pbuf_custom_ref', called by
yueee_yt 0:7766f6712673 638 * pbuf_free. */
yueee_yt 0:7766f6712673 639 static void
yueee_yt 0:7766f6712673 640 ipfrag_free_pbuf_custom(struct pbuf *p)
yueee_yt 0:7766f6712673 641 {
yueee_yt 0:7766f6712673 642 struct pbuf_custom_ref *pcr = (struct pbuf_custom_ref*)p;
yueee_yt 0:7766f6712673 643 LWIP_ASSERT("pcr != NULL", pcr != NULL);
yueee_yt 0:7766f6712673 644 LWIP_ASSERT("pcr == p", (void*)pcr == (void*)p);
yueee_yt 0:7766f6712673 645 if (pcr->original != NULL) {
yueee_yt 0:7766f6712673 646 pbuf_free(pcr->original);
yueee_yt 0:7766f6712673 647 }
yueee_yt 0:7766f6712673 648 ip_frag_free_pbuf_custom_ref(pcr);
yueee_yt 0:7766f6712673 649 }
yueee_yt 0:7766f6712673 650 #endif /* !LWIP_NETIF_TX_SINGLE_PBUF */
yueee_yt 0:7766f6712673 651 #endif /* IP_FRAG_USES_STATIC_BUF */
yueee_yt 0:7766f6712673 652
yueee_yt 0:7766f6712673 653 /**
yueee_yt 0:7766f6712673 654 * Fragment an IP datagram if too large for the netif.
yueee_yt 0:7766f6712673 655 *
yueee_yt 0:7766f6712673 656 * Chop the datagram in MTU sized chunks and send them in order
yueee_yt 0:7766f6712673 657 * by using a fixed size static memory buffer (PBUF_REF) or
yueee_yt 0:7766f6712673 658 * point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF).
yueee_yt 0:7766f6712673 659 *
yueee_yt 0:7766f6712673 660 * @param p ip packet to send
yueee_yt 0:7766f6712673 661 * @param netif the netif on which to send
yueee_yt 0:7766f6712673 662 * @param dest destination ip address to which to send
yueee_yt 0:7766f6712673 663 *
yueee_yt 0:7766f6712673 664 * @return ERR_OK if sent successfully, err_t otherwise
yueee_yt 0:7766f6712673 665 */
yueee_yt 0:7766f6712673 666 err_t
yueee_yt 0:7766f6712673 667 ip_frag(struct pbuf *p, struct netif *netif, ip_addr_t *dest)
yueee_yt 0:7766f6712673 668 {
yueee_yt 0:7766f6712673 669 struct pbuf *rambuf;
yueee_yt 0:7766f6712673 670 #if IP_FRAG_USES_STATIC_BUF
yueee_yt 0:7766f6712673 671 struct pbuf *header;
yueee_yt 0:7766f6712673 672 #else
yueee_yt 0:7766f6712673 673 #if !LWIP_NETIF_TX_SINGLE_PBUF
yueee_yt 0:7766f6712673 674 struct pbuf *newpbuf;
yueee_yt 0:7766f6712673 675 #endif
yueee_yt 0:7766f6712673 676 struct ip_hdr *original_iphdr;
yueee_yt 0:7766f6712673 677 #endif
yueee_yt 0:7766f6712673 678 struct ip_hdr *iphdr;
yueee_yt 0:7766f6712673 679 u16_t nfb;
yueee_yt 0:7766f6712673 680 u16_t left, cop;
yueee_yt 0:7766f6712673 681 u16_t mtu = netif->mtu;
yueee_yt 0:7766f6712673 682 u16_t ofo, omf;
yueee_yt 0:7766f6712673 683 u16_t last;
yueee_yt 0:7766f6712673 684 u16_t poff = IP_HLEN;
yueee_yt 0:7766f6712673 685 u16_t tmp;
yueee_yt 0:7766f6712673 686 #if !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF
yueee_yt 0:7766f6712673 687 u16_t newpbuflen = 0;
yueee_yt 0:7766f6712673 688 u16_t left_to_copy;
yueee_yt 0:7766f6712673 689 #endif
yueee_yt 0:7766f6712673 690
yueee_yt 0:7766f6712673 691 /* Get a RAM based MTU sized pbuf */
yueee_yt 0:7766f6712673 692 #if IP_FRAG_USES_STATIC_BUF
yueee_yt 0:7766f6712673 693 /* When using a static buffer, we use a PBUF_REF, which we will
yueee_yt 0:7766f6712673 694 * use to reference the packet (without link header).
yueee_yt 0:7766f6712673 695 * Layer and length is irrelevant.
yueee_yt 0:7766f6712673 696 */
yueee_yt 0:7766f6712673 697 rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
yueee_yt 0:7766f6712673 698 if (rambuf == NULL) {
yueee_yt 0:7766f6712673 699 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n"));
yueee_yt 0:7766f6712673 700 return ERR_MEM;
yueee_yt 0:7766f6712673 701 }
yueee_yt 0:7766f6712673 702 rambuf->tot_len = rambuf->len = mtu;
yueee_yt 0:7766f6712673 703 rambuf->payload = LWIP_MEM_ALIGN((void *)buf);
yueee_yt 0:7766f6712673 704
yueee_yt 0:7766f6712673 705 /* Copy the IP header in it */
yueee_yt 0:7766f6712673 706 iphdr = (struct ip_hdr *)rambuf->payload;
yueee_yt 0:7766f6712673 707 SMEMCPY(iphdr, p->payload, IP_HLEN);
yueee_yt 0:7766f6712673 708 #else /* IP_FRAG_USES_STATIC_BUF */
yueee_yt 0:7766f6712673 709 original_iphdr = (struct ip_hdr *)p->payload;
yueee_yt 0:7766f6712673 710 iphdr = original_iphdr;
yueee_yt 0:7766f6712673 711 #endif /* IP_FRAG_USES_STATIC_BUF */
yueee_yt 0:7766f6712673 712
yueee_yt 0:7766f6712673 713 /* Save original offset */
yueee_yt 0:7766f6712673 714 tmp = ntohs(IPH_OFFSET(iphdr));
yueee_yt 0:7766f6712673 715 ofo = tmp & IP_OFFMASK;
yueee_yt 0:7766f6712673 716 omf = tmp & IP_MF;
yueee_yt 0:7766f6712673 717
yueee_yt 0:7766f6712673 718 left = p->tot_len - IP_HLEN;
yueee_yt 0:7766f6712673 719
yueee_yt 0:7766f6712673 720 nfb = (mtu - IP_HLEN) / 8;
yueee_yt 0:7766f6712673 721
yueee_yt 0:7766f6712673 722 while (left) {
yueee_yt 0:7766f6712673 723 last = (left <= mtu - IP_HLEN);
yueee_yt 0:7766f6712673 724
yueee_yt 0:7766f6712673 725 /* Set new offset and MF flag */
yueee_yt 0:7766f6712673 726 tmp = omf | (IP_OFFMASK & (ofo));
yueee_yt 0:7766f6712673 727 if (!last) {
yueee_yt 0:7766f6712673 728 tmp = tmp | IP_MF;
yueee_yt 0:7766f6712673 729 }
yueee_yt 0:7766f6712673 730
yueee_yt 0:7766f6712673 731 /* Fill this fragment */
yueee_yt 0:7766f6712673 732 cop = last ? left : nfb * 8;
yueee_yt 0:7766f6712673 733
yueee_yt 0:7766f6712673 734 #if IP_FRAG_USES_STATIC_BUF
yueee_yt 0:7766f6712673 735 poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
yueee_yt 0:7766f6712673 736 #else /* IP_FRAG_USES_STATIC_BUF */
yueee_yt 0:7766f6712673 737 #if LWIP_NETIF_TX_SINGLE_PBUF
yueee_yt 0:7766f6712673 738 rambuf = pbuf_alloc(PBUF_IP, cop, PBUF_RAM);
yueee_yt 0:7766f6712673 739 if (rambuf == NULL) {
yueee_yt 0:7766f6712673 740 return ERR_MEM;
yueee_yt 0:7766f6712673 741 }
yueee_yt 0:7766f6712673 742 LWIP_ASSERT("this needs a pbuf in one piece!",
yueee_yt 0:7766f6712673 743 (rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
yueee_yt 0:7766f6712673 744 poff += pbuf_copy_partial(p, rambuf->payload, cop, poff);
yueee_yt 0:7766f6712673 745 /* make room for the IP header */
yueee_yt 0:7766f6712673 746 if(pbuf_header(rambuf, IP_HLEN)) {
yueee_yt 0:7766f6712673 747 pbuf_free(rambuf);
yueee_yt 0:7766f6712673 748 return ERR_MEM;
yueee_yt 0:7766f6712673 749 }
yueee_yt 0:7766f6712673 750 /* fill in the IP header */
yueee_yt 0:7766f6712673 751 SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
yueee_yt 0:7766f6712673 752 iphdr = rambuf->payload;
yueee_yt 0:7766f6712673 753 #else /* LWIP_NETIF_TX_SINGLE_PBUF */
yueee_yt 0:7766f6712673 754 /* When not using a static buffer, create a chain of pbufs.
yueee_yt 0:7766f6712673 755 * The first will be a PBUF_RAM holding the link and IP header.
yueee_yt 0:7766f6712673 756 * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
yueee_yt 0:7766f6712673 757 * but limited to the size of an mtu.
yueee_yt 0:7766f6712673 758 */
yueee_yt 0:7766f6712673 759 rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
yueee_yt 0:7766f6712673 760 if (rambuf == NULL) {
yueee_yt 0:7766f6712673 761 return ERR_MEM;
yueee_yt 0:7766f6712673 762 }
yueee_yt 0:7766f6712673 763 LWIP_ASSERT("this needs a pbuf in one piece!",
yueee_yt 0:7766f6712673 764 (p->len >= (IP_HLEN)));
yueee_yt 0:7766f6712673 765 SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
yueee_yt 0:7766f6712673 766 iphdr = (struct ip_hdr *)rambuf->payload;
yueee_yt 0:7766f6712673 767
yueee_yt 0:7766f6712673 768 /* Can just adjust p directly for needed offset. */
yueee_yt 0:7766f6712673 769 p->payload = (u8_t *)p->payload + poff;
yueee_yt 0:7766f6712673 770 p->len -= poff;
yueee_yt 0:7766f6712673 771
yueee_yt 0:7766f6712673 772 left_to_copy = cop;
yueee_yt 0:7766f6712673 773 while (left_to_copy) {
yueee_yt 0:7766f6712673 774 struct pbuf_custom_ref *pcr;
yueee_yt 0:7766f6712673 775 newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
yueee_yt 0:7766f6712673 776 /* Is this pbuf already empty? */
yueee_yt 0:7766f6712673 777 if (!newpbuflen) {
yueee_yt 0:7766f6712673 778 p = p->next;
yueee_yt 0:7766f6712673 779 continue;
yueee_yt 0:7766f6712673 780 }
yueee_yt 0:7766f6712673 781 pcr = ip_frag_alloc_pbuf_custom_ref();
yueee_yt 0:7766f6712673 782 if (pcr == NULL) {
yueee_yt 0:7766f6712673 783 pbuf_free(rambuf);
yueee_yt 0:7766f6712673 784 return ERR_MEM;
yueee_yt 0:7766f6712673 785 }
yueee_yt 0:7766f6712673 786 /* Mirror this pbuf, although we might not need all of it. */
yueee_yt 0:7766f6712673 787 newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
yueee_yt 0:7766f6712673 788 if (newpbuf == NULL) {
yueee_yt 0:7766f6712673 789 ip_frag_free_pbuf_custom_ref(pcr);
yueee_yt 0:7766f6712673 790 pbuf_free(rambuf);
yueee_yt 0:7766f6712673 791 return ERR_MEM;
yueee_yt 0:7766f6712673 792 }
yueee_yt 0:7766f6712673 793 pbuf_ref(p);
yueee_yt 0:7766f6712673 794 pcr->original = p;
yueee_yt 0:7766f6712673 795 pcr->pc.custom_free_function = ipfrag_free_pbuf_custom;
yueee_yt 0:7766f6712673 796
yueee_yt 0:7766f6712673 797 /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
yueee_yt 0:7766f6712673 798 * so that it is removed when pbuf_dechain is later called on rambuf.
yueee_yt 0:7766f6712673 799 */
yueee_yt 0:7766f6712673 800 pbuf_cat(rambuf, newpbuf);
yueee_yt 0:7766f6712673 801 left_to_copy -= newpbuflen;
yueee_yt 0:7766f6712673 802 if (left_to_copy) {
yueee_yt 0:7766f6712673 803 p = p->next;
yueee_yt 0:7766f6712673 804 }
yueee_yt 0:7766f6712673 805 }
yueee_yt 0:7766f6712673 806 poff = newpbuflen;
yueee_yt 0:7766f6712673 807 #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
yueee_yt 0:7766f6712673 808 #endif /* IP_FRAG_USES_STATIC_BUF */
yueee_yt 0:7766f6712673 809
yueee_yt 0:7766f6712673 810 /* Correct header */
yueee_yt 0:7766f6712673 811 IPH_OFFSET_SET(iphdr, htons(tmp));
yueee_yt 0:7766f6712673 812 IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
yueee_yt 0:7766f6712673 813 IPH_CHKSUM_SET(iphdr, 0);
yueee_yt 0:7766f6712673 814 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
yueee_yt 0:7766f6712673 815
yueee_yt 0:7766f6712673 816 #if IP_FRAG_USES_STATIC_BUF
yueee_yt 0:7766f6712673 817 if (last) {
yueee_yt 0:7766f6712673 818 pbuf_realloc(rambuf, left + IP_HLEN);
yueee_yt 0:7766f6712673 819 }
yueee_yt 0:7766f6712673 820
yueee_yt 0:7766f6712673 821 /* This part is ugly: we alloc a RAM based pbuf for
yueee_yt 0:7766f6712673 822 * the link level header for each chunk and then
yueee_yt 0:7766f6712673 823 * free it.A PBUF_ROM style pbuf for which pbuf_header
yueee_yt 0:7766f6712673 824 * worked would make things simpler.
yueee_yt 0:7766f6712673 825 */
yueee_yt 0:7766f6712673 826 header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
yueee_yt 0:7766f6712673 827 if (header != NULL) {
yueee_yt 0:7766f6712673 828 pbuf_chain(header, rambuf);
yueee_yt 0:7766f6712673 829 netif->output(netif, header, dest);
yueee_yt 0:7766f6712673 830 IPFRAG_STATS_INC(ip_frag.xmit);
yueee_yt 0:7766f6712673 831 snmp_inc_ipfragcreates();
yueee_yt 0:7766f6712673 832 pbuf_free(header);
yueee_yt 0:7766f6712673 833 } else {
yueee_yt 0:7766f6712673 834 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
yueee_yt 0:7766f6712673 835 pbuf_free(rambuf);
yueee_yt 0:7766f6712673 836 return ERR_MEM;
yueee_yt 0:7766f6712673 837 }
yueee_yt 0:7766f6712673 838 #else /* IP_FRAG_USES_STATIC_BUF */
yueee_yt 0:7766f6712673 839 /* No need for separate header pbuf - we allowed room for it in rambuf
yueee_yt 0:7766f6712673 840 * when allocated.
yueee_yt 0:7766f6712673 841 */
yueee_yt 0:7766f6712673 842 netif->output(netif, rambuf, dest);
yueee_yt 0:7766f6712673 843 IPFRAG_STATS_INC(ip_frag.xmit);
yueee_yt 0:7766f6712673 844
yueee_yt 0:7766f6712673 845 /* Unfortunately we can't reuse rambuf - the hardware may still be
yueee_yt 0:7766f6712673 846 * using the buffer. Instead we free it (and the ensuing chain) and
yueee_yt 0:7766f6712673 847 * recreate it next time round the loop. If we're lucky the hardware
yueee_yt 0:7766f6712673 848 * will have already sent the packet, the free will really free, and
yueee_yt 0:7766f6712673 849 * there will be zero memory penalty.
yueee_yt 0:7766f6712673 850 */
yueee_yt 0:7766f6712673 851
yueee_yt 0:7766f6712673 852 pbuf_free(rambuf);
yueee_yt 0:7766f6712673 853 #endif /* IP_FRAG_USES_STATIC_BUF */
yueee_yt 0:7766f6712673 854 left -= cop;
yueee_yt 0:7766f6712673 855 ofo += nfb;
yueee_yt 0:7766f6712673 856 }
yueee_yt 0:7766f6712673 857 #if IP_FRAG_USES_STATIC_BUF
yueee_yt 0:7766f6712673 858 pbuf_free(rambuf);
yueee_yt 0:7766f6712673 859 #endif /* IP_FRAG_USES_STATIC_BUF */
yueee_yt 0:7766f6712673 860 snmp_inc_ipfragoks();
yueee_yt 0:7766f6712673 861 return ERR_OK;
yueee_yt 0:7766f6712673 862 }
yueee_yt 0:7766f6712673 863 #endif /* IP_FRAG */