Kiyoshi Hayakawa / lwip

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core/ipv4/ip_frag.c@0:51ac1d130fd4, 2012-06-22 (annotated)

Committer:
mbed_official
Date:
Fri Jun 22 09:25:39 2012 +0000
Revision:
0:51ac1d130fd4
Initial import from lwip-1.4.0: http://download.savannah.gnu.org/releases/lwip/lwip-1.4.0.zip

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 0:51ac1d130fd4 1 /**
mbed_official 0:51ac1d130fd4 2 * @file
mbed_official 0:51ac1d130fd4 3 * This is the IPv4 packet segmentation and reassembly implementation.
mbed_official 0:51ac1d130fd4 4 *
mbed_official 0:51ac1d130fd4 5 */
mbed_official 0:51ac1d130fd4 6
mbed_official 0:51ac1d130fd4 7 /*
mbed_official 0:51ac1d130fd4 8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
mbed_official 0:51ac1d130fd4 9 * All rights reserved.
mbed_official 0:51ac1d130fd4 10 *
mbed_official 0:51ac1d130fd4 11 * Redistribution and use in source and binary forms, with or without modification,
mbed_official 0:51ac1d130fd4 12 * are permitted provided that the following conditions are met:
mbed_official 0:51ac1d130fd4 13 *
mbed_official 0:51ac1d130fd4 14 * 1. Redistributions of source code must retain the above copyright notice,
mbed_official 0:51ac1d130fd4 15 * this list of conditions and the following disclaimer.
mbed_official 0:51ac1d130fd4 16 * 2. Redistributions in binary form must reproduce the above copyright notice,
mbed_official 0:51ac1d130fd4 17 * this list of conditions and the following disclaimer in the documentation
mbed_official 0:51ac1d130fd4 18 * and/or other materials provided with the distribution.
mbed_official 0:51ac1d130fd4 19 * 3. The name of the author may not be used to endorse or promote products
mbed_official 0:51ac1d130fd4 20 * derived from this software without specific prior written permission.
mbed_official 0:51ac1d130fd4 21 *
mbed_official 0:51ac1d130fd4 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
mbed_official 0:51ac1d130fd4 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
mbed_official 0:51ac1d130fd4 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
mbed_official 0:51ac1d130fd4 25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
mbed_official 0:51ac1d130fd4 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
mbed_official 0:51ac1d130fd4 27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
mbed_official 0:51ac1d130fd4 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
mbed_official 0:51ac1d130fd4 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
mbed_official 0:51ac1d130fd4 30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
mbed_official 0:51ac1d130fd4 31 * OF SUCH DAMAGE.
mbed_official 0:51ac1d130fd4 32 *
mbed_official 0:51ac1d130fd4 33 * This file is part of the lwIP TCP/IP stack.
mbed_official 0:51ac1d130fd4 34 *
mbed_official 0:51ac1d130fd4 35 * Author: Jani Monoses <jani@iv.ro>
mbed_official 0:51ac1d130fd4 36 * Simon Goldschmidt
mbed_official 0:51ac1d130fd4 37 * original reassembly code by Adam Dunkels <adam@sics.se>
mbed_official 0:51ac1d130fd4 38 *
mbed_official 0:51ac1d130fd4 39 */
mbed_official 0:51ac1d130fd4 40
mbed_official 0:51ac1d130fd4 41 #include "lwip/opt.h"
mbed_official 0:51ac1d130fd4 42 #include "lwip/ip_frag.h"
mbed_official 0:51ac1d130fd4 43 #include "lwip/def.h"
mbed_official 0:51ac1d130fd4 44 #include "lwip/inet_chksum.h"
mbed_official 0:51ac1d130fd4 45 #include "lwip/netif.h"
mbed_official 0:51ac1d130fd4 46 #include "lwip/snmp.h"
mbed_official 0:51ac1d130fd4 47 #include "lwip/stats.h"
mbed_official 0:51ac1d130fd4 48 #include "lwip/icmp.h"
mbed_official 0:51ac1d130fd4 49
mbed_official 0:51ac1d130fd4 50 #include <string.h>
mbed_official 0:51ac1d130fd4 51
mbed_official 0:51ac1d130fd4 52 #if IP_REASSEMBLY
mbed_official 0:51ac1d130fd4 53 /**
mbed_official 0:51ac1d130fd4 54 * The IP reassembly code currently has the following limitations:
mbed_official 0:51ac1d130fd4 55 * - IP header options are not supported
mbed_official 0:51ac1d130fd4 56 * - fragments must not overlap (e.g. due to different routes),
mbed_official 0:51ac1d130fd4 57 * currently, overlapping or duplicate fragments are thrown away
mbed_official 0:51ac1d130fd4 58 * if IP_REASS_CHECK_OVERLAP=1 (the default)!
mbed_official 0:51ac1d130fd4 59 *
mbed_official 0:51ac1d130fd4 60 * @todo: work with IP header options
mbed_official 0:51ac1d130fd4 61 */
mbed_official 0:51ac1d130fd4 62
mbed_official 0:51ac1d130fd4 63 /** Setting this to 0, you can turn off checking the fragments for overlapping
mbed_official 0:51ac1d130fd4 64 * regions. The code gets a little smaller. Only use this if you know that
mbed_official 0:51ac1d130fd4 65 * overlapping won't occur on your network! */
mbed_official 0:51ac1d130fd4 66 #ifndef IP_REASS_CHECK_OVERLAP
mbed_official 0:51ac1d130fd4 67 #define IP_REASS_CHECK_OVERLAP 1
mbed_official 0:51ac1d130fd4 68 #endif /* IP_REASS_CHECK_OVERLAP */
mbed_official 0:51ac1d130fd4 69
mbed_official 0:51ac1d130fd4 70 /** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
mbed_official 0:51ac1d130fd4 71 * full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
mbed_official 0:51ac1d130fd4 72 * Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
mbed_official 0:51ac1d130fd4 73 * is set to 1, so one datagram can be reassembled at a time, only. */
mbed_official 0:51ac1d130fd4 74 #ifndef IP_REASS_FREE_OLDEST
mbed_official 0:51ac1d130fd4 75 #define IP_REASS_FREE_OLDEST 1
mbed_official 0:51ac1d130fd4 76 #endif /* IP_REASS_FREE_OLDEST */
mbed_official 0:51ac1d130fd4 77
mbed_official 0:51ac1d130fd4 78 #define IP_REASS_FLAG_LASTFRAG 0x01
mbed_official 0:51ac1d130fd4 79
mbed_official 0:51ac1d130fd4 80 /** This is a helper struct which holds the starting
mbed_official 0:51ac1d130fd4 81 * offset and the ending offset of this fragment to
mbed_official 0:51ac1d130fd4 82 * easily chain the fragments.
mbed_official 0:51ac1d130fd4 83 * It has the same packing requirements as the IP header, since it replaces
mbed_official 0:51ac1d130fd4 84 * the IP header in memory in incoming fragments (after copying it) to keep
mbed_official 0:51ac1d130fd4 85 * track of the various fragments. (-> If the IP header doesn't need packing,
mbed_official 0:51ac1d130fd4 86 * this struct doesn't need packing, too.)
mbed_official 0:51ac1d130fd4 87 */
mbed_official 0:51ac1d130fd4 88 #ifdef PACK_STRUCT_USE_INCLUDES
mbed_official 0:51ac1d130fd4 89 # include "arch/bpstruct.h"
mbed_official 0:51ac1d130fd4 90 #endif
mbed_official 0:51ac1d130fd4 91 PACK_STRUCT_BEGIN
mbed_official 0:51ac1d130fd4 92 struct ip_reass_helper {
mbed_official 0:51ac1d130fd4 93 PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
mbed_official 0:51ac1d130fd4 94 PACK_STRUCT_FIELD(u16_t start);
mbed_official 0:51ac1d130fd4 95 PACK_STRUCT_FIELD(u16_t end);
mbed_official 0:51ac1d130fd4 96 } PACK_STRUCT_STRUCT;
mbed_official 0:51ac1d130fd4 97 PACK_STRUCT_END
mbed_official 0:51ac1d130fd4 98 #ifdef PACK_STRUCT_USE_INCLUDES
mbed_official 0:51ac1d130fd4 99 # include "arch/epstruct.h"
mbed_official 0:51ac1d130fd4 100 #endif
mbed_official 0:51ac1d130fd4 101
mbed_official 0:51ac1d130fd4 102 #define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB) \
mbed_official 0:51ac1d130fd4 103 (ip_addr_cmp(&(iphdrA)->src, &(iphdrB)->src) && \
mbed_official 0:51ac1d130fd4 104 ip_addr_cmp(&(iphdrA)->dest, &(iphdrB)->dest) && \
mbed_official 0:51ac1d130fd4 105 IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0
mbed_official 0:51ac1d130fd4 106
mbed_official 0:51ac1d130fd4 107 /* global variables */
mbed_official 0:51ac1d130fd4 108 static struct ip_reassdata *reassdatagrams;
mbed_official 0:51ac1d130fd4 109 static u16_t ip_reass_pbufcount;
mbed_official 0:51ac1d130fd4 110
mbed_official 0:51ac1d130fd4 111 /* function prototypes */
mbed_official 0:51ac1d130fd4 112 static void ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
mbed_official 0:51ac1d130fd4 113 static int ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
mbed_official 0:51ac1d130fd4 114
mbed_official 0:51ac1d130fd4 115 /**
mbed_official 0:51ac1d130fd4 116 * Reassembly timer base function
mbed_official 0:51ac1d130fd4 117 * for both NO_SYS == 0 and 1 (!).
mbed_official 0:51ac1d130fd4 118 *
mbed_official 0:51ac1d130fd4 119 * Should be called every 1000 msec (defined by IP_TMR_INTERVAL).
mbed_official 0:51ac1d130fd4 120 */
mbed_official 0:51ac1d130fd4 121 void
mbed_official 0:51ac1d130fd4 122 ip_reass_tmr(void)
mbed_official 0:51ac1d130fd4 123 {
mbed_official 0:51ac1d130fd4 124 struct ip_reassdata *r, *prev = NULL;
mbed_official 0:51ac1d130fd4 125
mbed_official 0:51ac1d130fd4 126 r = reassdatagrams;
mbed_official 0:51ac1d130fd4 127 while (r != NULL) {
mbed_official 0:51ac1d130fd4 128 /* Decrement the timer. Once it reaches 0,
mbed_official 0:51ac1d130fd4 129 * clean up the incomplete fragment assembly */
mbed_official 0:51ac1d130fd4 130 if (r->timer > 0) {
mbed_official 0:51ac1d130fd4 131 r->timer--;
mbed_official 0:51ac1d130fd4 132 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)r->timer));
mbed_official 0:51ac1d130fd4 133 prev = r;
mbed_official 0:51ac1d130fd4 134 r = r->next;
mbed_official 0:51ac1d130fd4 135 } else {
mbed_official 0:51ac1d130fd4 136 /* reassembly timed out */
mbed_official 0:51ac1d130fd4 137 struct ip_reassdata *tmp;
mbed_official 0:51ac1d130fd4 138 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out\n"));
mbed_official 0:51ac1d130fd4 139 tmp = r;
mbed_official 0:51ac1d130fd4 140 /* get the next pointer before freeing */
mbed_official 0:51ac1d130fd4 141 r = r->next;
mbed_official 0:51ac1d130fd4 142 /* free the helper struct and all enqueued pbufs */
mbed_official 0:51ac1d130fd4 143 ip_reass_free_complete_datagram(tmp, prev);
mbed_official 0:51ac1d130fd4 144 }
mbed_official 0:51ac1d130fd4 145 }
mbed_official 0:51ac1d130fd4 146 }
mbed_official 0:51ac1d130fd4 147
mbed_official 0:51ac1d130fd4 148 /**
mbed_official 0:51ac1d130fd4 149 * Free a datagram (struct ip_reassdata) and all its pbufs.
mbed_official 0:51ac1d130fd4 150 * Updates the total count of enqueued pbufs (ip_reass_pbufcount),
mbed_official 0:51ac1d130fd4 151 * SNMP counters and sends an ICMP time exceeded packet.
mbed_official 0:51ac1d130fd4 152 *
mbed_official 0:51ac1d130fd4 153 * @param ipr datagram to free
mbed_official 0:51ac1d130fd4 154 * @param prev the previous datagram in the linked list
mbed_official 0:51ac1d130fd4 155 * @return the number of pbufs freed
mbed_official 0:51ac1d130fd4 156 */
mbed_official 0:51ac1d130fd4 157 static int
mbed_official 0:51ac1d130fd4 158 ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
mbed_official 0:51ac1d130fd4 159 {
mbed_official 0:51ac1d130fd4 160 u16_t pbufs_freed = 0;
mbed_official 0:51ac1d130fd4 161 u8_t clen;
mbed_official 0:51ac1d130fd4 162 struct pbuf *p;
mbed_official 0:51ac1d130fd4 163 struct ip_reass_helper *iprh;
mbed_official 0:51ac1d130fd4 164
mbed_official 0:51ac1d130fd4 165 LWIP_ASSERT("prev != ipr", prev != ipr);
mbed_official 0:51ac1d130fd4 166 if (prev != NULL) {
mbed_official 0:51ac1d130fd4 167 LWIP_ASSERT("prev->next == ipr", prev->next == ipr);
mbed_official 0:51ac1d130fd4 168 }
mbed_official 0:51ac1d130fd4 169
mbed_official 0:51ac1d130fd4 170 snmp_inc_ipreasmfails();
mbed_official 0:51ac1d130fd4 171 #if LWIP_ICMP
mbed_official 0:51ac1d130fd4 172 iprh = (struct ip_reass_helper *)ipr->p->payload;
mbed_official 0:51ac1d130fd4 173 if (iprh->start == 0) {
mbed_official 0:51ac1d130fd4 174 /* The first fragment was received, send ICMP time exceeded. */
mbed_official 0:51ac1d130fd4 175 /* First, de-queue the first pbuf from r->p. */
mbed_official 0:51ac1d130fd4 176 p = ipr->p;
mbed_official 0:51ac1d130fd4 177 ipr->p = iprh->next_pbuf;
mbed_official 0:51ac1d130fd4 178 /* Then, copy the original header into it. */
mbed_official 0:51ac1d130fd4 179 SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN);
mbed_official 0:51ac1d130fd4 180 icmp_time_exceeded(p, ICMP_TE_FRAG);
mbed_official 0:51ac1d130fd4 181 clen = pbuf_clen(p);
mbed_official 0:51ac1d130fd4 182 LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
mbed_official 0:51ac1d130fd4 183 pbufs_freed += clen;
mbed_official 0:51ac1d130fd4 184 pbuf_free(p);
mbed_official 0:51ac1d130fd4 185 }
mbed_official 0:51ac1d130fd4 186 #endif /* LWIP_ICMP */
mbed_official 0:51ac1d130fd4 187
mbed_official 0:51ac1d130fd4 188 /* First, free all received pbufs. The individual pbufs need to be released
mbed_official 0:51ac1d130fd4 189 separately as they have not yet been chained */
mbed_official 0:51ac1d130fd4 190 p = ipr->p;
mbed_official 0:51ac1d130fd4 191 while (p != NULL) {
mbed_official 0:51ac1d130fd4 192 struct pbuf *pcur;
mbed_official 0:51ac1d130fd4 193 iprh = (struct ip_reass_helper *)p->payload;
mbed_official 0:51ac1d130fd4 194 pcur = p;
mbed_official 0:51ac1d130fd4 195 /* get the next pointer before freeing */
mbed_official 0:51ac1d130fd4 196 p = iprh->next_pbuf;
mbed_official 0:51ac1d130fd4 197 clen = pbuf_clen(pcur);
mbed_official 0:51ac1d130fd4 198 LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
mbed_official 0:51ac1d130fd4 199 pbufs_freed += clen;
mbed_official 0:51ac1d130fd4 200 pbuf_free(pcur);
mbed_official 0:51ac1d130fd4 201 }
mbed_official 0:51ac1d130fd4 202 /* Then, unchain the struct ip_reassdata from the list and free it. */
mbed_official 0:51ac1d130fd4 203 ip_reass_dequeue_datagram(ipr, prev);
mbed_official 0:51ac1d130fd4 204 LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= pbufs_freed);
mbed_official 0:51ac1d130fd4 205 ip_reass_pbufcount -= pbufs_freed;
mbed_official 0:51ac1d130fd4 206
mbed_official 0:51ac1d130fd4 207 return pbufs_freed;
mbed_official 0:51ac1d130fd4 208 }
mbed_official 0:51ac1d130fd4 209
mbed_official 0:51ac1d130fd4 210 #if IP_REASS_FREE_OLDEST
mbed_official 0:51ac1d130fd4 211 /**
mbed_official 0:51ac1d130fd4 212 * Free the oldest datagram to make room for enqueueing new fragments.
mbed_official 0:51ac1d130fd4 213 * The datagram 'fraghdr' belongs to is not freed!
mbed_official 0:51ac1d130fd4 214 *
mbed_official 0:51ac1d130fd4 215 * @param fraghdr IP header of the current fragment
mbed_official 0:51ac1d130fd4 216 * @param pbufs_needed number of pbufs needed to enqueue
mbed_official 0:51ac1d130fd4 217 * (used for freeing other datagrams if not enough space)
mbed_official 0:51ac1d130fd4 218 * @return the number of pbufs freed
mbed_official 0:51ac1d130fd4 219 */
mbed_official 0:51ac1d130fd4 220 static int
mbed_official 0:51ac1d130fd4 221 ip_reass_remove_oldest_datagram(struct ip_hdr *fraghdr, int pbufs_needed)
mbed_official 0:51ac1d130fd4 222 {
mbed_official 0:51ac1d130fd4 223 /* @todo Can't we simply remove the last datagram in the
mbed_official 0:51ac1d130fd4 224 * linked list behind reassdatagrams?
mbed_official 0:51ac1d130fd4 225 */
mbed_official 0:51ac1d130fd4 226 struct ip_reassdata *r, *oldest, *prev;
mbed_official 0:51ac1d130fd4 227 int pbufs_freed = 0, pbufs_freed_current;
mbed_official 0:51ac1d130fd4 228 int other_datagrams;
mbed_official 0:51ac1d130fd4 229
mbed_official 0:51ac1d130fd4 230 /* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
mbed_official 0:51ac1d130fd4 231 * but don't free the datagram that 'fraghdr' belongs to! */
mbed_official 0:51ac1d130fd4 232 do {
mbed_official 0:51ac1d130fd4 233 oldest = NULL;
mbed_official 0:51ac1d130fd4 234 prev = NULL;
mbed_official 0:51ac1d130fd4 235 other_datagrams = 0;
mbed_official 0:51ac1d130fd4 236 r = reassdatagrams;
mbed_official 0:51ac1d130fd4 237 while (r != NULL) {
mbed_official 0:51ac1d130fd4 238 if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) {
mbed_official 0:51ac1d130fd4 239 /* Not the same datagram as fraghdr */
mbed_official 0:51ac1d130fd4 240 other_datagrams++;
mbed_official 0:51ac1d130fd4 241 if (oldest == NULL) {
mbed_official 0:51ac1d130fd4 242 oldest = r;
mbed_official 0:51ac1d130fd4 243 } else if (r->timer <= oldest->timer) {
mbed_official 0:51ac1d130fd4 244 /* older than the previous oldest */
mbed_official 0:51ac1d130fd4 245 oldest = r;
mbed_official 0:51ac1d130fd4 246 }
mbed_official 0:51ac1d130fd4 247 }
mbed_official 0:51ac1d130fd4 248 if (r->next != NULL) {
mbed_official 0:51ac1d130fd4 249 prev = r;
mbed_official 0:51ac1d130fd4 250 }
mbed_official 0:51ac1d130fd4 251 r = r->next;
mbed_official 0:51ac1d130fd4 252 }
mbed_official 0:51ac1d130fd4 253 if (oldest != NULL) {
mbed_official 0:51ac1d130fd4 254 pbufs_freed_current = ip_reass_free_complete_datagram(oldest, prev);
mbed_official 0:51ac1d130fd4 255 pbufs_freed += pbufs_freed_current;
mbed_official 0:51ac1d130fd4 256 }
mbed_official 0:51ac1d130fd4 257 } while ((pbufs_freed < pbufs_needed) && (other_datagrams > 1));
mbed_official 0:51ac1d130fd4 258 return pbufs_freed;
mbed_official 0:51ac1d130fd4 259 }
mbed_official 0:51ac1d130fd4 260 #endif /* IP_REASS_FREE_OLDEST */
mbed_official 0:51ac1d130fd4 261
mbed_official 0:51ac1d130fd4 262 /**
mbed_official 0:51ac1d130fd4 263 * Enqueues a new fragment into the fragment queue
mbed_official 0:51ac1d130fd4 264 * @param fraghdr points to the new fragments IP hdr
mbed_official 0:51ac1d130fd4 265 * @param clen number of pbufs needed to enqueue (used for freeing other datagrams if not enough space)
mbed_official 0:51ac1d130fd4 266 * @return A pointer to the queue location into which the fragment was enqueued
mbed_official 0:51ac1d130fd4 267 */
mbed_official 0:51ac1d130fd4 268 static struct ip_reassdata*
mbed_official 0:51ac1d130fd4 269 ip_reass_enqueue_new_datagram(struct ip_hdr *fraghdr, int clen)
mbed_official 0:51ac1d130fd4 270 {
mbed_official 0:51ac1d130fd4 271 struct ip_reassdata* ipr;
mbed_official 0:51ac1d130fd4 272 /* No matching previous fragment found, allocate a new reassdata struct */
mbed_official 0:51ac1d130fd4 273 ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
mbed_official 0:51ac1d130fd4 274 if (ipr == NULL) {
mbed_official 0:51ac1d130fd4 275 #if IP_REASS_FREE_OLDEST
mbed_official 0:51ac1d130fd4 276 if (ip_reass_remove_oldest_datagram(fraghdr, clen) >= clen) {
mbed_official 0:51ac1d130fd4 277 ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
mbed_official 0:51ac1d130fd4 278 }
mbed_official 0:51ac1d130fd4 279 if (ipr == NULL)
mbed_official 0:51ac1d130fd4 280 #endif /* IP_REASS_FREE_OLDEST */
mbed_official 0:51ac1d130fd4 281 {
mbed_official 0:51ac1d130fd4 282 IPFRAG_STATS_INC(ip_frag.memerr);
mbed_official 0:51ac1d130fd4 283 LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct\n"));
mbed_official 0:51ac1d130fd4 284 return NULL;
mbed_official 0:51ac1d130fd4 285 }
mbed_official 0:51ac1d130fd4 286 }
mbed_official 0:51ac1d130fd4 287 memset(ipr, 0, sizeof(struct ip_reassdata));
mbed_official 0:51ac1d130fd4 288 ipr->timer = IP_REASS_MAXAGE;
mbed_official 0:51ac1d130fd4 289
mbed_official 0:51ac1d130fd4 290 /* enqueue the new structure to the front of the list */
mbed_official 0:51ac1d130fd4 291 ipr->next = reassdatagrams;
mbed_official 0:51ac1d130fd4 292 reassdatagrams = ipr;
mbed_official 0:51ac1d130fd4 293 /* copy the ip header for later tests and input */
mbed_official 0:51ac1d130fd4 294 /* @todo: no ip options supported? */
mbed_official 0:51ac1d130fd4 295 SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN);
mbed_official 0:51ac1d130fd4 296 return ipr;
mbed_official 0:51ac1d130fd4 297 }
mbed_official 0:51ac1d130fd4 298
mbed_official 0:51ac1d130fd4 299 /**
mbed_official 0:51ac1d130fd4 300 * Dequeues a datagram from the datagram queue. Doesn't deallocate the pbufs.
mbed_official 0:51ac1d130fd4 301 * @param ipr points to the queue entry to dequeue
mbed_official 0:51ac1d130fd4 302 */
mbed_official 0:51ac1d130fd4 303 static void
mbed_official 0:51ac1d130fd4 304 ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
mbed_official 0:51ac1d130fd4 305 {
mbed_official 0:51ac1d130fd4 306
mbed_official 0:51ac1d130fd4 307 /* dequeue the reass struct */
mbed_official 0:51ac1d130fd4 308 if (reassdatagrams == ipr) {
mbed_official 0:51ac1d130fd4 309 /* it was the first in the list */
mbed_official 0:51ac1d130fd4 310 reassdatagrams = ipr->next;
mbed_official 0:51ac1d130fd4 311 } else {
mbed_official 0:51ac1d130fd4 312 /* it wasn't the first, so it must have a valid 'prev' */
mbed_official 0:51ac1d130fd4 313 LWIP_ASSERT("sanity check linked list", prev != NULL);
mbed_official 0:51ac1d130fd4 314 prev->next = ipr->next;
mbed_official 0:51ac1d130fd4 315 }
mbed_official 0:51ac1d130fd4 316
mbed_official 0:51ac1d130fd4 317 /* now we can free the ip_reass struct */
mbed_official 0:51ac1d130fd4 318 memp_free(MEMP_REASSDATA, ipr);
mbed_official 0:51ac1d130fd4 319 }
mbed_official 0:51ac1d130fd4 320
mbed_official 0:51ac1d130fd4 321 /**
mbed_official 0:51ac1d130fd4 322 * Chain a new pbuf into the pbuf list that composes the datagram. The pbuf list
mbed_official 0:51ac1d130fd4 323 * will grow over time as new pbufs are rx.
mbed_official 0:51ac1d130fd4 324 * Also checks that the datagram passes basic continuity checks (if the last
mbed_official 0:51ac1d130fd4 325 * fragment was received at least once).
mbed_official 0:51ac1d130fd4 326 * @param root_p points to the 'root' pbuf for the current datagram being assembled.
mbed_official 0:51ac1d130fd4 327 * @param new_p points to the pbuf for the current fragment
mbed_official 0:51ac1d130fd4 328 * @return 0 if invalid, >0 otherwise
mbed_official 0:51ac1d130fd4 329 */
mbed_official 0:51ac1d130fd4 330 static int
mbed_official 0:51ac1d130fd4 331 ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata *ipr, struct pbuf *new_p)
mbed_official 0:51ac1d130fd4 332 {
mbed_official 0:51ac1d130fd4 333 struct ip_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
mbed_official 0:51ac1d130fd4 334 struct pbuf *q;
mbed_official 0:51ac1d130fd4 335 u16_t offset,len;
mbed_official 0:51ac1d130fd4 336 struct ip_hdr *fraghdr;
mbed_official 0:51ac1d130fd4 337 int valid = 1;
mbed_official 0:51ac1d130fd4 338
mbed_official 0:51ac1d130fd4 339 /* Extract length and fragment offset from current fragment */
mbed_official 0:51ac1d130fd4 340 fraghdr = (struct ip_hdr*)new_p->payload;
mbed_official 0:51ac1d130fd4 341 len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
mbed_official 0:51ac1d130fd4 342 offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
mbed_official 0:51ac1d130fd4 343
mbed_official 0:51ac1d130fd4 344 /* overwrite the fragment's ip header from the pbuf with our helper struct,
mbed_official 0:51ac1d130fd4 345 * and setup the embedded helper structure. */
mbed_official 0:51ac1d130fd4 346 /* make sure the struct ip_reass_helper fits into the IP header */
mbed_official 0:51ac1d130fd4 347 LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN",
mbed_official 0:51ac1d130fd4 348 sizeof(struct ip_reass_helper) <= IP_HLEN);
mbed_official 0:51ac1d130fd4 349 iprh = (struct ip_reass_helper*)new_p->payload;
mbed_official 0:51ac1d130fd4 350 iprh->next_pbuf = NULL;
mbed_official 0:51ac1d130fd4 351 iprh->start = offset;
mbed_official 0:51ac1d130fd4 352 iprh->end = offset + len;
mbed_official 0:51ac1d130fd4 353
mbed_official 0:51ac1d130fd4 354 /* Iterate through until we either get to the end of the list (append),
mbed_official 0:51ac1d130fd4 355 * or we find on with a larger offset (insert). */
mbed_official 0:51ac1d130fd4 356 for (q = ipr->p; q != NULL;) {
mbed_official 0:51ac1d130fd4 357 iprh_tmp = (struct ip_reass_helper*)q->payload;
mbed_official 0:51ac1d130fd4 358 if (iprh->start < iprh_tmp->start) {
mbed_official 0:51ac1d130fd4 359 /* the new pbuf should be inserted before this */
mbed_official 0:51ac1d130fd4 360 iprh->next_pbuf = q;
mbed_official 0:51ac1d130fd4 361 if (iprh_prev != NULL) {
mbed_official 0:51ac1d130fd4 362 /* not the fragment with the lowest offset */
mbed_official 0:51ac1d130fd4 363 #if IP_REASS_CHECK_OVERLAP
mbed_official 0:51ac1d130fd4 364 if ((iprh->start < iprh_prev->end) || (iprh->end > iprh_tmp->start)) {
mbed_official 0:51ac1d130fd4 365 /* fragment overlaps with previous or following, throw away */
mbed_official 0:51ac1d130fd4 366 goto freepbuf;
mbed_official 0:51ac1d130fd4 367 }
mbed_official 0:51ac1d130fd4 368 #endif /* IP_REASS_CHECK_OVERLAP */
mbed_official 0:51ac1d130fd4 369 iprh_prev->next_pbuf = new_p;
mbed_official 0:51ac1d130fd4 370 } else {
mbed_official 0:51ac1d130fd4 371 /* fragment with the lowest offset */
mbed_official 0:51ac1d130fd4 372 ipr->p = new_p;
mbed_official 0:51ac1d130fd4 373 }
mbed_official 0:51ac1d130fd4 374 break;
mbed_official 0:51ac1d130fd4 375 } else if(iprh->start == iprh_tmp->start) {
mbed_official 0:51ac1d130fd4 376 /* received the same datagram twice: no need to keep the datagram */
mbed_official 0:51ac1d130fd4 377 goto freepbuf;
mbed_official 0:51ac1d130fd4 378 #if IP_REASS_CHECK_OVERLAP
mbed_official 0:51ac1d130fd4 379 } else if(iprh->start < iprh_tmp->end) {
mbed_official 0:51ac1d130fd4 380 /* overlap: no need to keep the new datagram */
mbed_official 0:51ac1d130fd4 381 goto freepbuf;
mbed_official 0:51ac1d130fd4 382 #endif /* IP_REASS_CHECK_OVERLAP */
mbed_official 0:51ac1d130fd4 383 } else {
mbed_official 0:51ac1d130fd4 384 /* Check if the fragments received so far have no wholes. */
mbed_official 0:51ac1d130fd4 385 if (iprh_prev != NULL) {
mbed_official 0:51ac1d130fd4 386 if (iprh_prev->end != iprh_tmp->start) {
mbed_official 0:51ac1d130fd4 387 /* There is a fragment missing between the current
mbed_official 0:51ac1d130fd4 388 * and the previous fragment */
mbed_official 0:51ac1d130fd4 389 valid = 0;
mbed_official 0:51ac1d130fd4 390 }
mbed_official 0:51ac1d130fd4 391 }
mbed_official 0:51ac1d130fd4 392 }
mbed_official 0:51ac1d130fd4 393 q = iprh_tmp->next_pbuf;
mbed_official 0:51ac1d130fd4 394 iprh_prev = iprh_tmp;
mbed_official 0:51ac1d130fd4 395 }
mbed_official 0:51ac1d130fd4 396
mbed_official 0:51ac1d130fd4 397 /* If q is NULL, then we made it to the end of the list. Determine what to do now */
mbed_official 0:51ac1d130fd4 398 if (q == NULL) {
mbed_official 0:51ac1d130fd4 399 if (iprh_prev != NULL) {
mbed_official 0:51ac1d130fd4 400 /* this is (for now), the fragment with the highest offset:
mbed_official 0:51ac1d130fd4 401 * chain it to the last fragment */
mbed_official 0:51ac1d130fd4 402 #if IP_REASS_CHECK_OVERLAP
mbed_official 0:51ac1d130fd4 403 LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
mbed_official 0:51ac1d130fd4 404 #endif /* IP_REASS_CHECK_OVERLAP */
mbed_official 0:51ac1d130fd4 405 iprh_prev->next_pbuf = new_p;
mbed_official 0:51ac1d130fd4 406 if (iprh_prev->end != iprh->start) {
mbed_official 0:51ac1d130fd4 407 valid = 0;
mbed_official 0:51ac1d130fd4 408 }
mbed_official 0:51ac1d130fd4 409 } else {
mbed_official 0:51ac1d130fd4 410 #if IP_REASS_CHECK_OVERLAP
mbed_official 0:51ac1d130fd4 411 LWIP_ASSERT("no previous fragment, this must be the first fragment!",
mbed_official 0:51ac1d130fd4 412 ipr->p == NULL);
mbed_official 0:51ac1d130fd4 413 #endif /* IP_REASS_CHECK_OVERLAP */
mbed_official 0:51ac1d130fd4 414 /* this is the first fragment we ever received for this ip datagram */
mbed_official 0:51ac1d130fd4 415 ipr->p = new_p;
mbed_official 0:51ac1d130fd4 416 }
mbed_official 0:51ac1d130fd4 417 }
mbed_official 0:51ac1d130fd4 418
mbed_official 0:51ac1d130fd4 419 /* At this point, the validation part begins: */
mbed_official 0:51ac1d130fd4 420 /* If we already received the last fragment */
mbed_official 0:51ac1d130fd4 421 if ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0) {
mbed_official 0:51ac1d130fd4 422 /* and had no wholes so far */
mbed_official 0:51ac1d130fd4 423 if (valid) {
mbed_official 0:51ac1d130fd4 424 /* then check if the rest of the fragments is here */
mbed_official 0:51ac1d130fd4 425 /* Check if the queue starts with the first datagram */
mbed_official 0:51ac1d130fd4 426 if (((struct ip_reass_helper*)ipr->p->payload)->start != 0) {
mbed_official 0:51ac1d130fd4 427 valid = 0;
mbed_official 0:51ac1d130fd4 428 } else {
mbed_official 0:51ac1d130fd4 429 /* and check that there are no wholes after this datagram */
mbed_official 0:51ac1d130fd4 430 iprh_prev = iprh;
mbed_official 0:51ac1d130fd4 431 q = iprh->next_pbuf;
mbed_official 0:51ac1d130fd4 432 while (q != NULL) {
mbed_official 0:51ac1d130fd4 433 iprh = (struct ip_reass_helper*)q->payload;
mbed_official 0:51ac1d130fd4 434 if (iprh_prev->end != iprh->start) {
mbed_official 0:51ac1d130fd4 435 valid = 0;
mbed_official 0:51ac1d130fd4 436 break;
mbed_official 0:51ac1d130fd4 437 }
mbed_official 0:51ac1d130fd4 438 iprh_prev = iprh;
mbed_official 0:51ac1d130fd4 439 q = iprh->next_pbuf;
mbed_official 0:51ac1d130fd4 440 }
mbed_official 0:51ac1d130fd4 441 /* if still valid, all fragments are received
mbed_official 0:51ac1d130fd4 442 * (because to the MF==0 already arrived */
mbed_official 0:51ac1d130fd4 443 if (valid) {
mbed_official 0:51ac1d130fd4 444 LWIP_ASSERT("sanity check", ipr->p != NULL);
mbed_official 0:51ac1d130fd4 445 LWIP_ASSERT("sanity check",
mbed_official 0:51ac1d130fd4 446 ((struct ip_reass_helper*)ipr->p->payload) != iprh);
mbed_official 0:51ac1d130fd4 447 LWIP_ASSERT("validate_datagram:next_pbuf!=NULL",
mbed_official 0:51ac1d130fd4 448 iprh->next_pbuf == NULL);
mbed_official 0:51ac1d130fd4 449 LWIP_ASSERT("validate_datagram:datagram end!=datagram len",
mbed_official 0:51ac1d130fd4 450 iprh->end == ipr->datagram_len);
mbed_official 0:51ac1d130fd4 451 }
mbed_official 0:51ac1d130fd4 452 }
mbed_official 0:51ac1d130fd4 453 }
mbed_official 0:51ac1d130fd4 454 /* If valid is 0 here, there are some fragments missing in the middle
mbed_official 0:51ac1d130fd4 455 * (since MF == 0 has already arrived). Such datagrams simply time out if
mbed_official 0:51ac1d130fd4 456 * no more fragments are received... */
mbed_official 0:51ac1d130fd4 457 return valid;
mbed_official 0:51ac1d130fd4 458 }
mbed_official 0:51ac1d130fd4 459 /* If we come here, not all fragments were received, yet! */
mbed_official 0:51ac1d130fd4 460 return 0; /* not yet valid! */
mbed_official 0:51ac1d130fd4 461 #if IP_REASS_CHECK_OVERLAP
mbed_official 0:51ac1d130fd4 462 freepbuf:
mbed_official 0:51ac1d130fd4 463 ip_reass_pbufcount -= pbuf_clen(new_p);
mbed_official 0:51ac1d130fd4 464 pbuf_free(new_p);
mbed_official 0:51ac1d130fd4 465 return 0;
mbed_official 0:51ac1d130fd4 466 #endif /* IP_REASS_CHECK_OVERLAP */
mbed_official 0:51ac1d130fd4 467 }
mbed_official 0:51ac1d130fd4 468
mbed_official 0:51ac1d130fd4 469 /**
mbed_official 0:51ac1d130fd4 470 * Reassembles incoming IP fragments into an IP datagram.
mbed_official 0:51ac1d130fd4 471 *
mbed_official 0:51ac1d130fd4 472 * @param p points to a pbuf chain of the fragment
mbed_official 0:51ac1d130fd4 473 * @return NULL if reassembly is incomplete, ? otherwise
mbed_official 0:51ac1d130fd4 474 */
mbed_official 0:51ac1d130fd4 475 struct pbuf *
mbed_official 0:51ac1d130fd4 476 ip_reass(struct pbuf *p)
mbed_official 0:51ac1d130fd4 477 {
mbed_official 0:51ac1d130fd4 478 struct pbuf *r;
mbed_official 0:51ac1d130fd4 479 struct ip_hdr *fraghdr;
mbed_official 0:51ac1d130fd4 480 struct ip_reassdata *ipr;
mbed_official 0:51ac1d130fd4 481 struct ip_reass_helper *iprh;
mbed_official 0:51ac1d130fd4 482 u16_t offset, len;
mbed_official 0:51ac1d130fd4 483 u8_t clen;
mbed_official 0:51ac1d130fd4 484 struct ip_reassdata *ipr_prev = NULL;
mbed_official 0:51ac1d130fd4 485
mbed_official 0:51ac1d130fd4 486 IPFRAG_STATS_INC(ip_frag.recv);
mbed_official 0:51ac1d130fd4 487 snmp_inc_ipreasmreqds();
mbed_official 0:51ac1d130fd4 488
mbed_official 0:51ac1d130fd4 489 fraghdr = (struct ip_hdr*)p->payload;
mbed_official 0:51ac1d130fd4 490
mbed_official 0:51ac1d130fd4 491 if ((IPH_HL(fraghdr) * 4) != IP_HLEN) {
mbed_official 0:51ac1d130fd4 492 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n"));
mbed_official 0:51ac1d130fd4 493 IPFRAG_STATS_INC(ip_frag.err);
mbed_official 0:51ac1d130fd4 494 goto nullreturn;
mbed_official 0:51ac1d130fd4 495 }
mbed_official 0:51ac1d130fd4 496
mbed_official 0:51ac1d130fd4 497 offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
mbed_official 0:51ac1d130fd4 498 len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
mbed_official 0:51ac1d130fd4 499
mbed_official 0:51ac1d130fd4 500 /* Check if we are allowed to enqueue more datagrams. */
mbed_official 0:51ac1d130fd4 501 clen = pbuf_clen(p);
mbed_official 0:51ac1d130fd4 502 if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
mbed_official 0:51ac1d130fd4 503 #if IP_REASS_FREE_OLDEST
mbed_official 0:51ac1d130fd4 504 if (!ip_reass_remove_oldest_datagram(fraghdr, clen) ||
mbed_official 0:51ac1d130fd4 505 ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
mbed_official 0:51ac1d130fd4 506 #endif /* IP_REASS_FREE_OLDEST */
mbed_official 0:51ac1d130fd4 507 {
mbed_official 0:51ac1d130fd4 508 /* No datagram could be freed and still too many pbufs enqueued */
mbed_official 0:51ac1d130fd4 509 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
mbed_official 0:51ac1d130fd4 510 ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
mbed_official 0:51ac1d130fd4 511 IPFRAG_STATS_INC(ip_frag.memerr);
mbed_official 0:51ac1d130fd4 512 /* @todo: send ICMP time exceeded here? */
mbed_official 0:51ac1d130fd4 513 /* drop this pbuf */
mbed_official 0:51ac1d130fd4 514 goto nullreturn;
mbed_official 0:51ac1d130fd4 515 }
mbed_official 0:51ac1d130fd4 516 }
mbed_official 0:51ac1d130fd4 517
mbed_official 0:51ac1d130fd4 518 /* Look for the datagram the fragment belongs to in the current datagram queue,
mbed_official 0:51ac1d130fd4 519 * remembering the previous in the queue for later dequeueing. */
mbed_official 0:51ac1d130fd4 520 for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
mbed_official 0:51ac1d130fd4 521 /* Check if the incoming fragment matches the one currently present
mbed_official 0:51ac1d130fd4 522 in the reassembly buffer. If so, we proceed with copying the
mbed_official 0:51ac1d130fd4 523 fragment into the buffer. */
mbed_official 0:51ac1d130fd4 524 if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
mbed_official 0:51ac1d130fd4 525 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
mbed_official 0:51ac1d130fd4 526 ntohs(IPH_ID(fraghdr))));
mbed_official 0:51ac1d130fd4 527 IPFRAG_STATS_INC(ip_frag.cachehit);
mbed_official 0:51ac1d130fd4 528 break;
mbed_official 0:51ac1d130fd4 529 }
mbed_official 0:51ac1d130fd4 530 ipr_prev = ipr;
mbed_official 0:51ac1d130fd4 531 }
mbed_official 0:51ac1d130fd4 532
mbed_official 0:51ac1d130fd4 533 if (ipr == NULL) {
mbed_official 0:51ac1d130fd4 534 /* Enqueue a new datagram into the datagram queue */
mbed_official 0:51ac1d130fd4 535 ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
mbed_official 0:51ac1d130fd4 536 /* Bail if unable to enqueue */
mbed_official 0:51ac1d130fd4 537 if(ipr == NULL) {
mbed_official 0:51ac1d130fd4 538 goto nullreturn;
mbed_official 0:51ac1d130fd4 539 }
mbed_official 0:51ac1d130fd4 540 } else {
mbed_official 0:51ac1d130fd4 541 if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) &&
mbed_official 0:51ac1d130fd4 542 ((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
mbed_official 0:51ac1d130fd4 543 /* ipr->iphdr is not the header from the first fragment, but fraghdr is
mbed_official 0:51ac1d130fd4 544 * -> copy fraghdr into ipr->iphdr since we want to have the header
mbed_official 0:51ac1d130fd4 545 * of the first fragment (for ICMP time exceeded and later, for copying
mbed_official 0:51ac1d130fd4 546 * all options, if supported)*/
mbed_official 0:51ac1d130fd4 547 SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
mbed_official 0:51ac1d130fd4 548 }
mbed_official 0:51ac1d130fd4 549 }
mbed_official 0:51ac1d130fd4 550 /* Track the current number of pbufs current 'in-flight', in order to limit
mbed_official 0:51ac1d130fd4 551 the number of fragments that may be enqueued at any one time */
mbed_official 0:51ac1d130fd4 552 ip_reass_pbufcount += clen;
mbed_official 0:51ac1d130fd4 553
mbed_official 0:51ac1d130fd4 554 /* At this point, we have either created a new entry or pointing
mbed_official 0:51ac1d130fd4 555 * to an existing one */
mbed_official 0:51ac1d130fd4 556
mbed_official 0:51ac1d130fd4 557 /* check for 'no more fragments', and update queue entry*/
mbed_official 0:51ac1d130fd4 558 if ((IPH_OFFSET(fraghdr) & PP_NTOHS(IP_MF)) == 0) {
mbed_official 0:51ac1d130fd4 559 ipr->flags |= IP_REASS_FLAG_LASTFRAG;
mbed_official 0:51ac1d130fd4 560 ipr->datagram_len = offset + len;
mbed_official 0:51ac1d130fd4 561 LWIP_DEBUGF(IP_REASS_DEBUG,
mbed_official 0:51ac1d130fd4 562 ("ip_reass: last fragment seen, total len %"S16_F"\n",
mbed_official 0:51ac1d130fd4 563 ipr->datagram_len));
mbed_official 0:51ac1d130fd4 564 }
mbed_official 0:51ac1d130fd4 565 /* find the right place to insert this pbuf */
mbed_official 0:51ac1d130fd4 566 /* @todo: trim pbufs if fragments are overlapping */
mbed_official 0:51ac1d130fd4 567 if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) {
mbed_official 0:51ac1d130fd4 568 /* the totally last fragment (flag more fragments = 0) was received at least
mbed_official 0:51ac1d130fd4 569 * once AND all fragments are received */
mbed_official 0:51ac1d130fd4 570 ipr->datagram_len += IP_HLEN;
mbed_official 0:51ac1d130fd4 571
mbed_official 0:51ac1d130fd4 572 /* save the second pbuf before copying the header over the pointer */
mbed_official 0:51ac1d130fd4 573 r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf;
mbed_official 0:51ac1d130fd4 574
mbed_official 0:51ac1d130fd4 575 /* copy the original ip header back to the first pbuf */
mbed_official 0:51ac1d130fd4 576 fraghdr = (struct ip_hdr*)(ipr->p->payload);
mbed_official 0:51ac1d130fd4 577 SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
mbed_official 0:51ac1d130fd4 578 IPH_LEN_SET(fraghdr, htons(ipr->datagram_len));
mbed_official 0:51ac1d130fd4 579 IPH_OFFSET_SET(fraghdr, 0);
mbed_official 0:51ac1d130fd4 580 IPH_CHKSUM_SET(fraghdr, 0);
mbed_official 0:51ac1d130fd4 581 /* @todo: do we need to set calculate the correct checksum? */
mbed_official 0:51ac1d130fd4 582 IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));
mbed_official 0:51ac1d130fd4 583
mbed_official 0:51ac1d130fd4 584 p = ipr->p;
mbed_official 0:51ac1d130fd4 585
mbed_official 0:51ac1d130fd4 586 /* chain together the pbufs contained within the reass_data list. */
mbed_official 0:51ac1d130fd4 587 while(r != NULL) {
mbed_official 0:51ac1d130fd4 588 iprh = (struct ip_reass_helper*)r->payload;
mbed_official 0:51ac1d130fd4 589
mbed_official 0:51ac1d130fd4 590 /* hide the ip header for every succeding fragment */
mbed_official 0:51ac1d130fd4 591 pbuf_header(r, -IP_HLEN);
mbed_official 0:51ac1d130fd4 592 pbuf_cat(p, r);
mbed_official 0:51ac1d130fd4 593 r = iprh->next_pbuf;
mbed_official 0:51ac1d130fd4 594 }
mbed_official 0:51ac1d130fd4 595 /* release the sources allocate for the fragment queue entry */
mbed_official 0:51ac1d130fd4 596 ip_reass_dequeue_datagram(ipr, ipr_prev);
mbed_official 0:51ac1d130fd4 597
mbed_official 0:51ac1d130fd4 598 /* and adjust the number of pbufs currently queued for reassembly. */
mbed_official 0:51ac1d130fd4 599 ip_reass_pbufcount -= pbuf_clen(p);
mbed_official 0:51ac1d130fd4 600
mbed_official 0:51ac1d130fd4 601 /* Return the pbuf chain */
mbed_official 0:51ac1d130fd4 602 return p;
mbed_official 0:51ac1d130fd4 603 }
mbed_official 0:51ac1d130fd4 604 /* the datagram is not (yet?) reassembled completely */
mbed_official 0:51ac1d130fd4 605 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
mbed_official 0:51ac1d130fd4 606 return NULL;
mbed_official 0:51ac1d130fd4 607
mbed_official 0:51ac1d130fd4 608 nullreturn:
mbed_official 0:51ac1d130fd4 609 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n"));
mbed_official 0:51ac1d130fd4 610 IPFRAG_STATS_INC(ip_frag.drop);
mbed_official 0:51ac1d130fd4 611 pbuf_free(p);
mbed_official 0:51ac1d130fd4 612 return NULL;
mbed_official 0:51ac1d130fd4 613 }
mbed_official 0:51ac1d130fd4 614 #endif /* IP_REASSEMBLY */
mbed_official 0:51ac1d130fd4 615
mbed_official 0:51ac1d130fd4 616 #if IP_FRAG
mbed_official 0:51ac1d130fd4 617 #if IP_FRAG_USES_STATIC_BUF
mbed_official 0:51ac1d130fd4 618 static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU + MEM_ALIGNMENT - 1)];
mbed_official 0:51ac1d130fd4 619 #else /* IP_FRAG_USES_STATIC_BUF */
mbed_official 0:51ac1d130fd4 620
mbed_official 0:51ac1d130fd4 621 #if !LWIP_NETIF_TX_SINGLE_PBUF
mbed_official 0:51ac1d130fd4 622 /** Allocate a new struct pbuf_custom_ref */
mbed_official 0:51ac1d130fd4 623 static struct pbuf_custom_ref*
mbed_official 0:51ac1d130fd4 624 ip_frag_alloc_pbuf_custom_ref(void)
mbed_official 0:51ac1d130fd4 625 {
mbed_official 0:51ac1d130fd4 626 return (struct pbuf_custom_ref*)memp_malloc(MEMP_FRAG_PBUF);
mbed_official 0:51ac1d130fd4 627 }
mbed_official 0:51ac1d130fd4 628
mbed_official 0:51ac1d130fd4 629 /** Free a struct pbuf_custom_ref */
mbed_official 0:51ac1d130fd4 630 static void
mbed_official 0:51ac1d130fd4 631 ip_frag_free_pbuf_custom_ref(struct pbuf_custom_ref* p)
mbed_official 0:51ac1d130fd4 632 {
mbed_official 0:51ac1d130fd4 633 LWIP_ASSERT("p != NULL", p != NULL);
mbed_official 0:51ac1d130fd4 634 memp_free(MEMP_FRAG_PBUF, p);
mbed_official 0:51ac1d130fd4 635 }
mbed_official 0:51ac1d130fd4 636
mbed_official 0:51ac1d130fd4 637 /** Free-callback function to free a 'struct pbuf_custom_ref', called by
mbed_official 0:51ac1d130fd4 638 * pbuf_free. */
mbed_official 0:51ac1d130fd4 639 static void
mbed_official 0:51ac1d130fd4 640 ipfrag_free_pbuf_custom(struct pbuf *p)
mbed_official 0:51ac1d130fd4 641 {
mbed_official 0:51ac1d130fd4 642 struct pbuf_custom_ref *pcr = (struct pbuf_custom_ref*)p;
mbed_official 0:51ac1d130fd4 643 LWIP_ASSERT("pcr != NULL", pcr != NULL);
mbed_official 0:51ac1d130fd4 644 LWIP_ASSERT("pcr == p", (void*)pcr == (void*)p);
mbed_official 0:51ac1d130fd4 645 if (pcr->original != NULL) {
mbed_official 0:51ac1d130fd4 646 pbuf_free(pcr->original);
mbed_official 0:51ac1d130fd4 647 }
mbed_official 0:51ac1d130fd4 648 ip_frag_free_pbuf_custom_ref(pcr);
mbed_official 0:51ac1d130fd4 649 }
mbed_official 0:51ac1d130fd4 650 #endif /* !LWIP_NETIF_TX_SINGLE_PBUF */
mbed_official 0:51ac1d130fd4 651 #endif /* IP_FRAG_USES_STATIC_BUF */
mbed_official 0:51ac1d130fd4 652
mbed_official 0:51ac1d130fd4 653 /**
mbed_official 0:51ac1d130fd4 654 * Fragment an IP datagram if too large for the netif.
mbed_official 0:51ac1d130fd4 655 *
mbed_official 0:51ac1d130fd4 656 * Chop the datagram in MTU sized chunks and send them in order
mbed_official 0:51ac1d130fd4 657 * by using a fixed size static memory buffer (PBUF_REF) or
mbed_official 0:51ac1d130fd4 658 * point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF).
mbed_official 0:51ac1d130fd4 659 *
mbed_official 0:51ac1d130fd4 660 * @param p ip packet to send
mbed_official 0:51ac1d130fd4 661 * @param netif the netif on which to send
mbed_official 0:51ac1d130fd4 662 * @param dest destination ip address to which to send
mbed_official 0:51ac1d130fd4 663 *
mbed_official 0:51ac1d130fd4 664 * @return ERR_OK if sent successfully, err_t otherwise
mbed_official 0:51ac1d130fd4 665 */
mbed_official 0:51ac1d130fd4 666 err_t
mbed_official 0:51ac1d130fd4 667 ip_frag(struct pbuf *p, struct netif *netif, ip_addr_t *dest)
mbed_official 0:51ac1d130fd4 668 {
mbed_official 0:51ac1d130fd4 669 struct pbuf *rambuf;
mbed_official 0:51ac1d130fd4 670 #if IP_FRAG_USES_STATIC_BUF
mbed_official 0:51ac1d130fd4 671 struct pbuf *header;
mbed_official 0:51ac1d130fd4 672 #else
mbed_official 0:51ac1d130fd4 673 #if !LWIP_NETIF_TX_SINGLE_PBUF
mbed_official 0:51ac1d130fd4 674 struct pbuf *newpbuf;
mbed_official 0:51ac1d130fd4 675 #endif
mbed_official 0:51ac1d130fd4 676 struct ip_hdr *original_iphdr;
mbed_official 0:51ac1d130fd4 677 #endif
mbed_official 0:51ac1d130fd4 678 struct ip_hdr *iphdr;
mbed_official 0:51ac1d130fd4 679 u16_t nfb;
mbed_official 0:51ac1d130fd4 680 u16_t left, cop;
mbed_official 0:51ac1d130fd4 681 u16_t mtu = netif->mtu;
mbed_official 0:51ac1d130fd4 682 u16_t ofo, omf;
mbed_official 0:51ac1d130fd4 683 u16_t last;
mbed_official 0:51ac1d130fd4 684 u16_t poff = IP_HLEN;
mbed_official 0:51ac1d130fd4 685 u16_t tmp;
mbed_official 0:51ac1d130fd4 686 #if !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF
mbed_official 0:51ac1d130fd4 687 u16_t newpbuflen = 0;
mbed_official 0:51ac1d130fd4 688 u16_t left_to_copy;
mbed_official 0:51ac1d130fd4 689 #endif
mbed_official 0:51ac1d130fd4 690
mbed_official 0:51ac1d130fd4 691 /* Get a RAM based MTU sized pbuf */
mbed_official 0:51ac1d130fd4 692 #if IP_FRAG_USES_STATIC_BUF
mbed_official 0:51ac1d130fd4 693 /* When using a static buffer, we use a PBUF_REF, which we will
mbed_official 0:51ac1d130fd4 694 * use to reference the packet (without link header).
mbed_official 0:51ac1d130fd4 695 * Layer and length is irrelevant.
mbed_official 0:51ac1d130fd4 696 */
mbed_official 0:51ac1d130fd4 697 rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
mbed_official 0:51ac1d130fd4 698 if (rambuf == NULL) {
mbed_official 0:51ac1d130fd4 699 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n"));
mbed_official 0:51ac1d130fd4 700 return ERR_MEM;
mbed_official 0:51ac1d130fd4 701 }
mbed_official 0:51ac1d130fd4 702 rambuf->tot_len = rambuf->len = mtu;
mbed_official 0:51ac1d130fd4 703 rambuf->payload = LWIP_MEM_ALIGN((void *)buf);
mbed_official 0:51ac1d130fd4 704
mbed_official 0:51ac1d130fd4 705 /* Copy the IP header in it */
mbed_official 0:51ac1d130fd4 706 iphdr = (struct ip_hdr *)rambuf->payload;
mbed_official 0:51ac1d130fd4 707 SMEMCPY(iphdr, p->payload, IP_HLEN);
mbed_official 0:51ac1d130fd4 708 #else /* IP_FRAG_USES_STATIC_BUF */
mbed_official 0:51ac1d130fd4 709 original_iphdr = (struct ip_hdr *)p->payload;
mbed_official 0:51ac1d130fd4 710 iphdr = original_iphdr;
mbed_official 0:51ac1d130fd4 711 #endif /* IP_FRAG_USES_STATIC_BUF */
mbed_official 0:51ac1d130fd4 712
mbed_official 0:51ac1d130fd4 713 /* Save original offset */
mbed_official 0:51ac1d130fd4 714 tmp = ntohs(IPH_OFFSET(iphdr));
mbed_official 0:51ac1d130fd4 715 ofo = tmp & IP_OFFMASK;
mbed_official 0:51ac1d130fd4 716 omf = tmp & IP_MF;
mbed_official 0:51ac1d130fd4 717
mbed_official 0:51ac1d130fd4 718 left = p->tot_len - IP_HLEN;
mbed_official 0:51ac1d130fd4 719
mbed_official 0:51ac1d130fd4 720 nfb = (mtu - IP_HLEN) / 8;
mbed_official 0:51ac1d130fd4 721
mbed_official 0:51ac1d130fd4 722 while (left) {
mbed_official 0:51ac1d130fd4 723 last = (left <= mtu - IP_HLEN);
mbed_official 0:51ac1d130fd4 724
mbed_official 0:51ac1d130fd4 725 /* Set new offset and MF flag */
mbed_official 0:51ac1d130fd4 726 tmp = omf | (IP_OFFMASK & (ofo));
mbed_official 0:51ac1d130fd4 727 if (!last) {
mbed_official 0:51ac1d130fd4 728 tmp = tmp | IP_MF;
mbed_official 0:51ac1d130fd4 729 }
mbed_official 0:51ac1d130fd4 730
mbed_official 0:51ac1d130fd4 731 /* Fill this fragment */
mbed_official 0:51ac1d130fd4 732 cop = last ? left : nfb * 8;
mbed_official 0:51ac1d130fd4 733
mbed_official 0:51ac1d130fd4 734 #if IP_FRAG_USES_STATIC_BUF
mbed_official 0:51ac1d130fd4 735 poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
mbed_official 0:51ac1d130fd4 736 #else /* IP_FRAG_USES_STATIC_BUF */
mbed_official 0:51ac1d130fd4 737 #if LWIP_NETIF_TX_SINGLE_PBUF
mbed_official 0:51ac1d130fd4 738 rambuf = pbuf_alloc(PBUF_IP, cop, PBUF_RAM);
mbed_official 0:51ac1d130fd4 739 if (rambuf == NULL) {
mbed_official 0:51ac1d130fd4 740 return ERR_MEM;
mbed_official 0:51ac1d130fd4 741 }
mbed_official 0:51ac1d130fd4 742 LWIP_ASSERT("this needs a pbuf in one piece!",
mbed_official 0:51ac1d130fd4 743 (rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
mbed_official 0:51ac1d130fd4 744 poff += pbuf_copy_partial(p, rambuf->payload, cop, poff);
mbed_official 0:51ac1d130fd4 745 /* make room for the IP header */
mbed_official 0:51ac1d130fd4 746 if(pbuf_header(rambuf, IP_HLEN)) {
mbed_official 0:51ac1d130fd4 747 pbuf_free(rambuf);
mbed_official 0:51ac1d130fd4 748 return ERR_MEM;
mbed_official 0:51ac1d130fd4 749 }
mbed_official 0:51ac1d130fd4 750 /* fill in the IP header */
mbed_official 0:51ac1d130fd4 751 SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
mbed_official 0:51ac1d130fd4 752 iphdr = rambuf->payload;
mbed_official 0:51ac1d130fd4 753 #else /* LWIP_NETIF_TX_SINGLE_PBUF */
mbed_official 0:51ac1d130fd4 754 /* When not using a static buffer, create a chain of pbufs.
mbed_official 0:51ac1d130fd4 755 * The first will be a PBUF_RAM holding the link and IP header.
mbed_official 0:51ac1d130fd4 756 * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
mbed_official 0:51ac1d130fd4 757 * but limited to the size of an mtu.
mbed_official 0:51ac1d130fd4 758 */
mbed_official 0:51ac1d130fd4 759 rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
mbed_official 0:51ac1d130fd4 760 if (rambuf == NULL) {
mbed_official 0:51ac1d130fd4 761 return ERR_MEM;
mbed_official 0:51ac1d130fd4 762 }
mbed_official 0:51ac1d130fd4 763 LWIP_ASSERT("this needs a pbuf in one piece!",
mbed_official 0:51ac1d130fd4 764 (p->len >= (IP_HLEN)));
mbed_official 0:51ac1d130fd4 765 SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
mbed_official 0:51ac1d130fd4 766 iphdr = (struct ip_hdr *)rambuf->payload;
mbed_official 0:51ac1d130fd4 767
mbed_official 0:51ac1d130fd4 768 /* Can just adjust p directly for needed offset. */
mbed_official 0:51ac1d130fd4 769 p->payload = (u8_t *)p->payload + poff;
mbed_official 0:51ac1d130fd4 770 p->len -= poff;
mbed_official 0:51ac1d130fd4 771
mbed_official 0:51ac1d130fd4 772 left_to_copy = cop;
mbed_official 0:51ac1d130fd4 773 while (left_to_copy) {
mbed_official 0:51ac1d130fd4 774 struct pbuf_custom_ref *pcr;
mbed_official 0:51ac1d130fd4 775 newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
mbed_official 0:51ac1d130fd4 776 /* Is this pbuf already empty? */
mbed_official 0:51ac1d130fd4 777 if (!newpbuflen) {
mbed_official 0:51ac1d130fd4 778 p = p->next;
mbed_official 0:51ac1d130fd4 779 continue;
mbed_official 0:51ac1d130fd4 780 }
mbed_official 0:51ac1d130fd4 781 pcr = ip_frag_alloc_pbuf_custom_ref();
mbed_official 0:51ac1d130fd4 782 if (pcr == NULL) {
mbed_official 0:51ac1d130fd4 783 pbuf_free(rambuf);
mbed_official 0:51ac1d130fd4 784 return ERR_MEM;
mbed_official 0:51ac1d130fd4 785 }
mbed_official 0:51ac1d130fd4 786 /* Mirror this pbuf, although we might not need all of it. */
mbed_official 0:51ac1d130fd4 787 newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
mbed_official 0:51ac1d130fd4 788 if (newpbuf == NULL) {
mbed_official 0:51ac1d130fd4 789 ip_frag_free_pbuf_custom_ref(pcr);
mbed_official 0:51ac1d130fd4 790 pbuf_free(rambuf);
mbed_official 0:51ac1d130fd4 791 return ERR_MEM;
mbed_official 0:51ac1d130fd4 792 }
mbed_official 0:51ac1d130fd4 793 pbuf_ref(p);
mbed_official 0:51ac1d130fd4 794 pcr->original = p;
mbed_official 0:51ac1d130fd4 795 pcr->pc.custom_free_function = ipfrag_free_pbuf_custom;
mbed_official 0:51ac1d130fd4 796
mbed_official 0:51ac1d130fd4 797 /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
mbed_official 0:51ac1d130fd4 798 * so that it is removed when pbuf_dechain is later called on rambuf.
mbed_official 0:51ac1d130fd4 799 */
mbed_official 0:51ac1d130fd4 800 pbuf_cat(rambuf, newpbuf);
mbed_official 0:51ac1d130fd4 801 left_to_copy -= newpbuflen;
mbed_official 0:51ac1d130fd4 802 if (left_to_copy) {
mbed_official 0:51ac1d130fd4 803 p = p->next;
mbed_official 0:51ac1d130fd4 804 }
mbed_official 0:51ac1d130fd4 805 }
mbed_official 0:51ac1d130fd4 806 poff = newpbuflen;
mbed_official 0:51ac1d130fd4 807 #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
mbed_official 0:51ac1d130fd4 808 #endif /* IP_FRAG_USES_STATIC_BUF */
mbed_official 0:51ac1d130fd4 809
mbed_official 0:51ac1d130fd4 810 /* Correct header */
mbed_official 0:51ac1d130fd4 811 IPH_OFFSET_SET(iphdr, htons(tmp));
mbed_official 0:51ac1d130fd4 812 IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
mbed_official 0:51ac1d130fd4 813 IPH_CHKSUM_SET(iphdr, 0);
mbed_official 0:51ac1d130fd4 814 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
mbed_official 0:51ac1d130fd4 815
mbed_official 0:51ac1d130fd4 816 #if IP_FRAG_USES_STATIC_BUF
mbed_official 0:51ac1d130fd4 817 if (last) {
mbed_official 0:51ac1d130fd4 818 pbuf_realloc(rambuf, left + IP_HLEN);
mbed_official 0:51ac1d130fd4 819 }
mbed_official 0:51ac1d130fd4 820
mbed_official 0:51ac1d130fd4 821 /* This part is ugly: we alloc a RAM based pbuf for
mbed_official 0:51ac1d130fd4 822 * the link level header for each chunk and then
mbed_official 0:51ac1d130fd4 823 * free it.A PBUF_ROM style pbuf for which pbuf_header
mbed_official 0:51ac1d130fd4 824 * worked would make things simpler.
mbed_official 0:51ac1d130fd4 825 */
mbed_official 0:51ac1d130fd4 826 header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
mbed_official 0:51ac1d130fd4 827 if (header != NULL) {
mbed_official 0:51ac1d130fd4 828 pbuf_chain(header, rambuf);
mbed_official 0:51ac1d130fd4 829 netif->output(netif, header, dest);
mbed_official 0:51ac1d130fd4 830 IPFRAG_STATS_INC(ip_frag.xmit);
mbed_official 0:51ac1d130fd4 831 snmp_inc_ipfragcreates();
mbed_official 0:51ac1d130fd4 832 pbuf_free(header);
mbed_official 0:51ac1d130fd4 833 } else {
mbed_official 0:51ac1d130fd4 834 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
mbed_official 0:51ac1d130fd4 835 pbuf_free(rambuf);
mbed_official 0:51ac1d130fd4 836 return ERR_MEM;
mbed_official 0:51ac1d130fd4 837 }
mbed_official 0:51ac1d130fd4 838 #else /* IP_FRAG_USES_STATIC_BUF */
mbed_official 0:51ac1d130fd4 839 /* No need for separate header pbuf - we allowed room for it in rambuf
mbed_official 0:51ac1d130fd4 840 * when allocated.
mbed_official 0:51ac1d130fd4 841 */
mbed_official 0:51ac1d130fd4 842 netif->output(netif, rambuf, dest);
mbed_official 0:51ac1d130fd4 843 IPFRAG_STATS_INC(ip_frag.xmit);
mbed_official 0:51ac1d130fd4 844
mbed_official 0:51ac1d130fd4 845 /* Unfortunately we can't reuse rambuf - the hardware may still be
mbed_official 0:51ac1d130fd4 846 * using the buffer. Instead we free it (and the ensuing chain) and
mbed_official 0:51ac1d130fd4 847 * recreate it next time round the loop. If we're lucky the hardware
mbed_official 0:51ac1d130fd4 848 * will have already sent the packet, the free will really free, and
mbed_official 0:51ac1d130fd4 849 * there will be zero memory penalty.
mbed_official 0:51ac1d130fd4 850 */
mbed_official 0:51ac1d130fd4 851
mbed_official 0:51ac1d130fd4 852 pbuf_free(rambuf);
mbed_official 0:51ac1d130fd4 853 #endif /* IP_FRAG_USES_STATIC_BUF */
mbed_official 0:51ac1d130fd4 854 left -= cop;
mbed_official 0:51ac1d130fd4 855 ofo += nfb;
mbed_official 0:51ac1d130fd4 856 }
mbed_official 0:51ac1d130fd4 857 #if IP_FRAG_USES_STATIC_BUF
mbed_official 0:51ac1d130fd4 858 pbuf_free(rambuf);
mbed_official 0:51ac1d130fd4 859 #endif /* IP_FRAG_USES_STATIC_BUF */
mbed_official 0:51ac1d130fd4 860 snmp_inc_ipfragoks();
mbed_official 0:51ac1d130fd4 861 return ERR_OK;
mbed_official 0:51ac1d130fd4 862 }
mbed_official 0:51ac1d130fd4 863 #endif /* IP_FRAG */