Pascal Nysten / lwip

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Dependencies:   DebugLib

Dependents:   LoRaWAN-lmic-app LoRaWAN-lmic-app LoRaWAN-test-10secs LoRaPersonalizedDeviceForEverynet ... more

Fork of lwip_ppp_ethernet by Donatien Garnier

src/core/ipv4/ip_frag.c@0:8e01dca41002, 2012-05-24 (annotated)

Committer:
donatien
Date:
Thu May 24 15:53:48 2012 +0000
Revision:
0:8e01dca41002
Merge with Emilio's LwIp

Who changed what in which revision?

UserRevisionLine numberNew contents of line
donatien 0:8e01dca41002 1 /**
donatien 0:8e01dca41002 2 * @file
donatien 0:8e01dca41002 3 * This is the IPv4 packet segmentation and reassembly implementation.
donatien 0:8e01dca41002 4 *
donatien 0:8e01dca41002 5 */
donatien 0:8e01dca41002 6
donatien 0:8e01dca41002 7 /*
donatien 0:8e01dca41002 8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
donatien 0:8e01dca41002 9 * All rights reserved.
donatien 0:8e01dca41002 10 *
donatien 0:8e01dca41002 11 * Redistribution and use in source and binary forms, with or without modification,
donatien 0:8e01dca41002 12 * are permitted provided that the following conditions are met:
donatien 0:8e01dca41002 13 *
donatien 0:8e01dca41002 14 * 1. Redistributions of source code must retain the above copyright notice,
donatien 0:8e01dca41002 15 * this list of conditions and the following disclaimer.
donatien 0:8e01dca41002 16 * 2. Redistributions in binary form must reproduce the above copyright notice,
donatien 0:8e01dca41002 17 * this list of conditions and the following disclaimer in the documentation
donatien 0:8e01dca41002 18 * and/or other materials provided with the distribution.
donatien 0:8e01dca41002 19 * 3. The name of the author may not be used to endorse or promote products
donatien 0:8e01dca41002 20 * derived from this software without specific prior written permission.
donatien 0:8e01dca41002 21 *
donatien 0:8e01dca41002 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
donatien 0:8e01dca41002 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
donatien 0:8e01dca41002 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
donatien 0:8e01dca41002 25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
donatien 0:8e01dca41002 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
donatien 0:8e01dca41002 27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
donatien 0:8e01dca41002 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
donatien 0:8e01dca41002 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
donatien 0:8e01dca41002 30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
donatien 0:8e01dca41002 31 * OF SUCH DAMAGE.
donatien 0:8e01dca41002 32 *
donatien 0:8e01dca41002 33 * This file is part of the lwIP TCP/IP stack.
donatien 0:8e01dca41002 34 *
donatien 0:8e01dca41002 35 * Author: Jani Monoses <jani@iv.ro>
donatien 0:8e01dca41002 36 * Simon Goldschmidt
donatien 0:8e01dca41002 37 * original reassembly code by Adam Dunkels <adam@sics.se>
donatien 0:8e01dca41002 38 *
donatien 0:8e01dca41002 39 */
donatien 0:8e01dca41002 40
donatien 0:8e01dca41002 41 #include "lwip/opt.h"
donatien 0:8e01dca41002 42 #include "lwip/ip_frag.h"
donatien 0:8e01dca41002 43 #include "lwip/def.h"
donatien 0:8e01dca41002 44 #include "lwip/inet_chksum.h"
donatien 0:8e01dca41002 45 #include "lwip/netif.h"
donatien 0:8e01dca41002 46 #include "lwip/snmp.h"
donatien 0:8e01dca41002 47 #include "lwip/stats.h"
donatien 0:8e01dca41002 48 #include "lwip/icmp.h"
donatien 0:8e01dca41002 49
donatien 0:8e01dca41002 50 #include <string.h>
donatien 0:8e01dca41002 51
donatien 0:8e01dca41002 52 #if IP_REASSEMBLY
donatien 0:8e01dca41002 53 /**
donatien 0:8e01dca41002 54 * The IP reassembly code currently has the following limitations:
donatien 0:8e01dca41002 55 * - IP header options are not supported
donatien 0:8e01dca41002 56 * - fragments must not overlap (e.g. due to different routes),
donatien 0:8e01dca41002 57 * currently, overlapping or duplicate fragments are thrown away
donatien 0:8e01dca41002 58 * if IP_REASS_CHECK_OVERLAP=1 (the default)!
donatien 0:8e01dca41002 59 *
donatien 0:8e01dca41002 60 * @todo: work with IP header options
donatien 0:8e01dca41002 61 */
donatien 0:8e01dca41002 62
donatien 0:8e01dca41002 63 /** Setting this to 0, you can turn off checking the fragments for overlapping
donatien 0:8e01dca41002 64 * regions. The code gets a little smaller. Only use this if you know that
donatien 0:8e01dca41002 65 * overlapping won't occur on your network! */
donatien 0:8e01dca41002 66 #ifndef IP_REASS_CHECK_OVERLAP
donatien 0:8e01dca41002 67 #define IP_REASS_CHECK_OVERLAP 1
donatien 0:8e01dca41002 68 #endif /* IP_REASS_CHECK_OVERLAP */
donatien 0:8e01dca41002 69
donatien 0:8e01dca41002 70 /** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
donatien 0:8e01dca41002 71 * full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
donatien 0:8e01dca41002 72 * Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
donatien 0:8e01dca41002 73 * is set to 1, so one datagram can be reassembled at a time, only. */
donatien 0:8e01dca41002 74 #ifndef IP_REASS_FREE_OLDEST
donatien 0:8e01dca41002 75 #define IP_REASS_FREE_OLDEST 1
donatien 0:8e01dca41002 76 #endif /* IP_REASS_FREE_OLDEST */
donatien 0:8e01dca41002 77
donatien 0:8e01dca41002 78 #define IP_REASS_FLAG_LASTFRAG 0x01
donatien 0:8e01dca41002 79
donatien 0:8e01dca41002 80 /** This is a helper struct which holds the starting
donatien 0:8e01dca41002 81 * offset and the ending offset of this fragment to
donatien 0:8e01dca41002 82 * easily chain the fragments.
donatien 0:8e01dca41002 83 * It has the same packing requirements as the IP header, since it replaces
donatien 0:8e01dca41002 84 * the IP header in memory in incoming fragments (after copying it) to keep
donatien 0:8e01dca41002 85 * track of the various fragments. (-> If the IP header doesn't need packing,
donatien 0:8e01dca41002 86 * this struct doesn't need packing, too.)
donatien 0:8e01dca41002 87 */
donatien 0:8e01dca41002 88 #ifdef PACK_STRUCT_USE_INCLUDES
donatien 0:8e01dca41002 89 # include "arch/bpstruct.h"
donatien 0:8e01dca41002 90 #endif
donatien 0:8e01dca41002 91 PACK_STRUCT_BEGIN
donatien 0:8e01dca41002 92 struct ip_reass_helper {
donatien 0:8e01dca41002 93 PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
donatien 0:8e01dca41002 94 PACK_STRUCT_FIELD(u16_t start);
donatien 0:8e01dca41002 95 PACK_STRUCT_FIELD(u16_t end);
donatien 0:8e01dca41002 96 } PACK_STRUCT_STRUCT;
donatien 0:8e01dca41002 97 PACK_STRUCT_END
donatien 0:8e01dca41002 98 #ifdef PACK_STRUCT_USE_INCLUDES
donatien 0:8e01dca41002 99 # include "arch/epstruct.h"
donatien 0:8e01dca41002 100 #endif
donatien 0:8e01dca41002 101
donatien 0:8e01dca41002 102 #define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB) \
donatien 0:8e01dca41002 103 (ip_addr_cmp(&(iphdrA)->src, &(iphdrB)->src) && \
donatien 0:8e01dca41002 104 ip_addr_cmp(&(iphdrA)->dest, &(iphdrB)->dest) && \
donatien 0:8e01dca41002 105 IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0
donatien 0:8e01dca41002 106
donatien 0:8e01dca41002 107 /* global variables */
donatien 0:8e01dca41002 108 static struct ip_reassdata *reassdatagrams;
donatien 0:8e01dca41002 109 static u16_t ip_reass_pbufcount;
donatien 0:8e01dca41002 110
donatien 0:8e01dca41002 111 /* function prototypes */
donatien 0:8e01dca41002 112 static void ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
donatien 0:8e01dca41002 113 static int ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
donatien 0:8e01dca41002 114
donatien 0:8e01dca41002 115 /**
donatien 0:8e01dca41002 116 * Reassembly timer base function
donatien 0:8e01dca41002 117 * for both NO_SYS == 0 and 1 (!).
donatien 0:8e01dca41002 118 *
donatien 0:8e01dca41002 119 * Should be called every 1000 msec (defined by IP_TMR_INTERVAL).
donatien 0:8e01dca41002 120 */
donatien 0:8e01dca41002 121 void
donatien 0:8e01dca41002 122 ip_reass_tmr(void)
donatien 0:8e01dca41002 123 {
donatien 0:8e01dca41002 124 struct ip_reassdata *r, *prev = NULL;
donatien 0:8e01dca41002 125
donatien 0:8e01dca41002 126 r = reassdatagrams;
donatien 0:8e01dca41002 127 while (r != NULL) {
donatien 0:8e01dca41002 128 /* Decrement the timer. Once it reaches 0,
donatien 0:8e01dca41002 129 * clean up the incomplete fragment assembly */
donatien 0:8e01dca41002 130 if (r->timer > 0) {
donatien 0:8e01dca41002 131 r->timer--;
donatien 0:8e01dca41002 132 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)r->timer));
donatien 0:8e01dca41002 133 prev = r;
donatien 0:8e01dca41002 134 r = r->next;
donatien 0:8e01dca41002 135 } else {
donatien 0:8e01dca41002 136 /* reassembly timed out */
donatien 0:8e01dca41002 137 struct ip_reassdata *tmp;
donatien 0:8e01dca41002 138 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out\n"));
donatien 0:8e01dca41002 139 tmp = r;
donatien 0:8e01dca41002 140 /* get the next pointer before freeing */
donatien 0:8e01dca41002 141 r = r->next;
donatien 0:8e01dca41002 142 /* free the helper struct and all enqueued pbufs */
donatien 0:8e01dca41002 143 ip_reass_free_complete_datagram(tmp, prev);
donatien 0:8e01dca41002 144 }
donatien 0:8e01dca41002 145 }
donatien 0:8e01dca41002 146 }
donatien 0:8e01dca41002 147
donatien 0:8e01dca41002 148 /**
donatien 0:8e01dca41002 149 * Free a datagram (struct ip_reassdata) and all its pbufs.
donatien 0:8e01dca41002 150 * Updates the total count of enqueued pbufs (ip_reass_pbufcount),
donatien 0:8e01dca41002 151 * SNMP counters and sends an ICMP time exceeded packet.
donatien 0:8e01dca41002 152 *
donatien 0:8e01dca41002 153 * @param ipr datagram to free
donatien 0:8e01dca41002 154 * @param prev the previous datagram in the linked list
donatien 0:8e01dca41002 155 * @return the number of pbufs freed
donatien 0:8e01dca41002 156 */
donatien 0:8e01dca41002 157 static int
donatien 0:8e01dca41002 158 ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
donatien 0:8e01dca41002 159 {
donatien 0:8e01dca41002 160 u16_t pbufs_freed = 0;
donatien 0:8e01dca41002 161 u8_t clen;
donatien 0:8e01dca41002 162 struct pbuf *p;
donatien 0:8e01dca41002 163 struct ip_reass_helper *iprh;
donatien 0:8e01dca41002 164
donatien 0:8e01dca41002 165 LWIP_ASSERT("prev != ipr", prev != ipr);
donatien 0:8e01dca41002 166 if (prev != NULL) {
donatien 0:8e01dca41002 167 LWIP_ASSERT("prev->next == ipr", prev->next == ipr);
donatien 0:8e01dca41002 168 }
donatien 0:8e01dca41002 169
donatien 0:8e01dca41002 170 snmp_inc_ipreasmfails();
donatien 0:8e01dca41002 171 #if LWIP_ICMP
donatien 0:8e01dca41002 172 iprh = (struct ip_reass_helper *)ipr->p->payload;
donatien 0:8e01dca41002 173 if (iprh->start == 0) {
donatien 0:8e01dca41002 174 /* The first fragment was received, send ICMP time exceeded. */
donatien 0:8e01dca41002 175 /* First, de-queue the first pbuf from r->p. */
donatien 0:8e01dca41002 176 p = ipr->p;
donatien 0:8e01dca41002 177 ipr->p = iprh->next_pbuf;
donatien 0:8e01dca41002 178 /* Then, copy the original header into it. */
donatien 0:8e01dca41002 179 SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN);
donatien 0:8e01dca41002 180 icmp_time_exceeded(p, ICMP_TE_FRAG);
donatien 0:8e01dca41002 181 clen = pbuf_clen(p);
donatien 0:8e01dca41002 182 LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
donatien 0:8e01dca41002 183 pbufs_freed += clen;
donatien 0:8e01dca41002 184 pbuf_free(p);
donatien 0:8e01dca41002 185 }
donatien 0:8e01dca41002 186 #endif /* LWIP_ICMP */
donatien 0:8e01dca41002 187
donatien 0:8e01dca41002 188 /* First, free all received pbufs. The individual pbufs need to be released
donatien 0:8e01dca41002 189 separately as they have not yet been chained */
donatien 0:8e01dca41002 190 p = ipr->p;
donatien 0:8e01dca41002 191 while (p != NULL) {
donatien 0:8e01dca41002 192 struct pbuf *pcur;
donatien 0:8e01dca41002 193 iprh = (struct ip_reass_helper *)p->payload;
donatien 0:8e01dca41002 194 pcur = p;
donatien 0:8e01dca41002 195 /* get the next pointer before freeing */
donatien 0:8e01dca41002 196 p = iprh->next_pbuf;
donatien 0:8e01dca41002 197 clen = pbuf_clen(pcur);
donatien 0:8e01dca41002 198 LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
donatien 0:8e01dca41002 199 pbufs_freed += clen;
donatien 0:8e01dca41002 200 pbuf_free(pcur);
donatien 0:8e01dca41002 201 }
donatien 0:8e01dca41002 202 /* Then, unchain the struct ip_reassdata from the list and free it. */
donatien 0:8e01dca41002 203 ip_reass_dequeue_datagram(ipr, prev);
donatien 0:8e01dca41002 204 LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= pbufs_freed);
donatien 0:8e01dca41002 205 ip_reass_pbufcount -= pbufs_freed;
donatien 0:8e01dca41002 206
donatien 0:8e01dca41002 207 return pbufs_freed;
donatien 0:8e01dca41002 208 }
donatien 0:8e01dca41002 209
donatien 0:8e01dca41002 210 #if IP_REASS_FREE_OLDEST
donatien 0:8e01dca41002 211 /**
donatien 0:8e01dca41002 212 * Free the oldest datagram to make room for enqueueing new fragments.
donatien 0:8e01dca41002 213 * The datagram 'fraghdr' belongs to is not freed!
donatien 0:8e01dca41002 214 *
donatien 0:8e01dca41002 215 * @param fraghdr IP header of the current fragment
donatien 0:8e01dca41002 216 * @param pbufs_needed number of pbufs needed to enqueue
donatien 0:8e01dca41002 217 * (used for freeing other datagrams if not enough space)
donatien 0:8e01dca41002 218 * @return the number of pbufs freed
donatien 0:8e01dca41002 219 */
donatien 0:8e01dca41002 220 static int
donatien 0:8e01dca41002 221 ip_reass_remove_oldest_datagram(struct ip_hdr *fraghdr, int pbufs_needed)
donatien 0:8e01dca41002 222 {
donatien 0:8e01dca41002 223 /* @todo Can't we simply remove the last datagram in the
donatien 0:8e01dca41002 224 * linked list behind reassdatagrams?
donatien 0:8e01dca41002 225 */
donatien 0:8e01dca41002 226 struct ip_reassdata *r, *oldest, *prev;
donatien 0:8e01dca41002 227 int pbufs_freed = 0, pbufs_freed_current;
donatien 0:8e01dca41002 228 int other_datagrams;
donatien 0:8e01dca41002 229
donatien 0:8e01dca41002 230 /* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
donatien 0:8e01dca41002 231 * but don't free the datagram that 'fraghdr' belongs to! */
donatien 0:8e01dca41002 232 do {
donatien 0:8e01dca41002 233 oldest = NULL;
donatien 0:8e01dca41002 234 prev = NULL;
donatien 0:8e01dca41002 235 other_datagrams = 0;
donatien 0:8e01dca41002 236 r = reassdatagrams;
donatien 0:8e01dca41002 237 while (r != NULL) {
donatien 0:8e01dca41002 238 if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) {
donatien 0:8e01dca41002 239 /* Not the same datagram as fraghdr */
donatien 0:8e01dca41002 240 other_datagrams++;
donatien 0:8e01dca41002 241 if (oldest == NULL) {
donatien 0:8e01dca41002 242 oldest = r;
donatien 0:8e01dca41002 243 } else if (r->timer <= oldest->timer) {
donatien 0:8e01dca41002 244 /* older than the previous oldest */
donatien 0:8e01dca41002 245 oldest = r;
donatien 0:8e01dca41002 246 }
donatien 0:8e01dca41002 247 }
donatien 0:8e01dca41002 248 if (r->next != NULL) {
donatien 0:8e01dca41002 249 prev = r;
donatien 0:8e01dca41002 250 }
donatien 0:8e01dca41002 251 r = r->next;
donatien 0:8e01dca41002 252 }
donatien 0:8e01dca41002 253 if (oldest != NULL) {
donatien 0:8e01dca41002 254 pbufs_freed_current = ip_reass_free_complete_datagram(oldest, prev);
donatien 0:8e01dca41002 255 pbufs_freed += pbufs_freed_current;
donatien 0:8e01dca41002 256 }
donatien 0:8e01dca41002 257 } while ((pbufs_freed < pbufs_needed) && (other_datagrams > 1));
donatien 0:8e01dca41002 258 return pbufs_freed;
donatien 0:8e01dca41002 259 }
donatien 0:8e01dca41002 260 #endif /* IP_REASS_FREE_OLDEST */
donatien 0:8e01dca41002 261
donatien 0:8e01dca41002 262 /**
donatien 0:8e01dca41002 263 * Enqueues a new fragment into the fragment queue
donatien 0:8e01dca41002 264 * @param fraghdr points to the new fragments IP hdr
donatien 0:8e01dca41002 265 * @param clen number of pbufs needed to enqueue (used for freeing other datagrams if not enough space)
donatien 0:8e01dca41002 266 * @return A pointer to the queue location into which the fragment was enqueued
donatien 0:8e01dca41002 267 */
donatien 0:8e01dca41002 268 static struct ip_reassdata*
donatien 0:8e01dca41002 269 ip_reass_enqueue_new_datagram(struct ip_hdr *fraghdr, int clen)
donatien 0:8e01dca41002 270 {
donatien 0:8e01dca41002 271 struct ip_reassdata* ipr;
donatien 0:8e01dca41002 272 /* No matching previous fragment found, allocate a new reassdata struct */
donatien 0:8e01dca41002 273 ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
donatien 0:8e01dca41002 274 if (ipr == NULL) {
donatien 0:8e01dca41002 275 #if IP_REASS_FREE_OLDEST
donatien 0:8e01dca41002 276 if (ip_reass_remove_oldest_datagram(fraghdr, clen) >= clen) {
donatien 0:8e01dca41002 277 ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
donatien 0:8e01dca41002 278 }
donatien 0:8e01dca41002 279 if (ipr == NULL)
donatien 0:8e01dca41002 280 #endif /* IP_REASS_FREE_OLDEST */
donatien 0:8e01dca41002 281 {
donatien 0:8e01dca41002 282 IPFRAG_STATS_INC(ip_frag.memerr);
donatien 0:8e01dca41002 283 LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct\n"));
donatien 0:8e01dca41002 284 return NULL;
donatien 0:8e01dca41002 285 }
donatien 0:8e01dca41002 286 }
donatien 0:8e01dca41002 287 memset(ipr, 0, sizeof(struct ip_reassdata));
donatien 0:8e01dca41002 288 ipr->timer = IP_REASS_MAXAGE;
donatien 0:8e01dca41002 289
donatien 0:8e01dca41002 290 /* enqueue the new structure to the front of the list */
donatien 0:8e01dca41002 291 ipr->next = reassdatagrams;
donatien 0:8e01dca41002 292 reassdatagrams = ipr;
donatien 0:8e01dca41002 293 /* copy the ip header for later tests and input */
donatien 0:8e01dca41002 294 /* @todo: no ip options supported? */
donatien 0:8e01dca41002 295 SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN);
donatien 0:8e01dca41002 296 return ipr;
donatien 0:8e01dca41002 297 }
donatien 0:8e01dca41002 298
donatien 0:8e01dca41002 299 /**
donatien 0:8e01dca41002 300 * Dequeues a datagram from the datagram queue. Doesn't deallocate the pbufs.
donatien 0:8e01dca41002 301 * @param ipr points to the queue entry to dequeue
donatien 0:8e01dca41002 302 */
donatien 0:8e01dca41002 303 static void
donatien 0:8e01dca41002 304 ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
donatien 0:8e01dca41002 305 {
donatien 0:8e01dca41002 306
donatien 0:8e01dca41002 307 /* dequeue the reass struct */
donatien 0:8e01dca41002 308 if (reassdatagrams == ipr) {
donatien 0:8e01dca41002 309 /* it was the first in the list */
donatien 0:8e01dca41002 310 reassdatagrams = ipr->next;
donatien 0:8e01dca41002 311 } else {
donatien 0:8e01dca41002 312 /* it wasn't the first, so it must have a valid 'prev' */
donatien 0:8e01dca41002 313 LWIP_ASSERT("sanity check linked list", prev != NULL);
donatien 0:8e01dca41002 314 prev->next = ipr->next;
donatien 0:8e01dca41002 315 }
donatien 0:8e01dca41002 316
donatien 0:8e01dca41002 317 /* now we can free the ip_reass struct */
donatien 0:8e01dca41002 318 memp_free(MEMP_REASSDATA, ipr);
donatien 0:8e01dca41002 319 }
donatien 0:8e01dca41002 320
donatien 0:8e01dca41002 321 /**
donatien 0:8e01dca41002 322 * Chain a new pbuf into the pbuf list that composes the datagram. The pbuf list
donatien 0:8e01dca41002 323 * will grow over time as new pbufs are rx.
donatien 0:8e01dca41002 324 * Also checks that the datagram passes basic continuity checks (if the last
donatien 0:8e01dca41002 325 * fragment was received at least once).
donatien 0:8e01dca41002 326 * @param root_p points to the 'root' pbuf for the current datagram being assembled.
donatien 0:8e01dca41002 327 * @param new_p points to the pbuf for the current fragment
donatien 0:8e01dca41002 328 * @return 0 if invalid, >0 otherwise
donatien 0:8e01dca41002 329 */
donatien 0:8e01dca41002 330 static int
donatien 0:8e01dca41002 331 ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata *ipr, struct pbuf *new_p)
donatien 0:8e01dca41002 332 {
donatien 0:8e01dca41002 333 struct ip_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
donatien 0:8e01dca41002 334 struct pbuf *q;
donatien 0:8e01dca41002 335 u16_t offset,len;
donatien 0:8e01dca41002 336 struct ip_hdr *fraghdr;
donatien 0:8e01dca41002 337 int valid = 1;
donatien 0:8e01dca41002 338
donatien 0:8e01dca41002 339 /* Extract length and fragment offset from current fragment */
donatien 0:8e01dca41002 340 fraghdr = (struct ip_hdr*)new_p->payload;
donatien 0:8e01dca41002 341 len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
donatien 0:8e01dca41002 342 offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
donatien 0:8e01dca41002 343
donatien 0:8e01dca41002 344 /* overwrite the fragment's ip header from the pbuf with our helper struct,
donatien 0:8e01dca41002 345 * and setup the embedded helper structure. */
donatien 0:8e01dca41002 346 /* make sure the struct ip_reass_helper fits into the IP header */
donatien 0:8e01dca41002 347 LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN",
donatien 0:8e01dca41002 348 sizeof(struct ip_reass_helper) <= IP_HLEN);
donatien 0:8e01dca41002 349 iprh = (struct ip_reass_helper*)new_p->payload;
donatien 0:8e01dca41002 350 iprh->next_pbuf = NULL;
donatien 0:8e01dca41002 351 iprh->start = offset;
donatien 0:8e01dca41002 352 iprh->end = offset + len;
donatien 0:8e01dca41002 353
donatien 0:8e01dca41002 354 /* Iterate through until we either get to the end of the list (append),
donatien 0:8e01dca41002 355 * or we find on with a larger offset (insert). */
donatien 0:8e01dca41002 356 for (q = ipr->p; q != NULL;) {
donatien 0:8e01dca41002 357 iprh_tmp = (struct ip_reass_helper*)q->payload;
donatien 0:8e01dca41002 358 if (iprh->start < iprh_tmp->start) {
donatien 0:8e01dca41002 359 /* the new pbuf should be inserted before this */
donatien 0:8e01dca41002 360 iprh->next_pbuf = q;
donatien 0:8e01dca41002 361 if (iprh_prev != NULL) {
donatien 0:8e01dca41002 362 /* not the fragment with the lowest offset */
donatien 0:8e01dca41002 363 #if IP_REASS_CHECK_OVERLAP
donatien 0:8e01dca41002 364 if ((iprh->start < iprh_prev->end) || (iprh->end > iprh_tmp->start)) {
donatien 0:8e01dca41002 365 /* fragment overlaps with previous or following, throw away */
donatien 0:8e01dca41002 366 goto freepbuf;
donatien 0:8e01dca41002 367 }
donatien 0:8e01dca41002 368 #endif /* IP_REASS_CHECK_OVERLAP */
donatien 0:8e01dca41002 369 iprh_prev->next_pbuf = new_p;
donatien 0:8e01dca41002 370 } else {
donatien 0:8e01dca41002 371 /* fragment with the lowest offset */
donatien 0:8e01dca41002 372 ipr->p = new_p;
donatien 0:8e01dca41002 373 }
donatien 0:8e01dca41002 374 break;
donatien 0:8e01dca41002 375 } else if(iprh->start == iprh_tmp->start) {
donatien 0:8e01dca41002 376 /* received the same datagram twice: no need to keep the datagram */
donatien 0:8e01dca41002 377 goto freepbuf;
donatien 0:8e01dca41002 378 #if IP_REASS_CHECK_OVERLAP
donatien 0:8e01dca41002 379 } else if(iprh->start < iprh_tmp->end) {
donatien 0:8e01dca41002 380 /* overlap: no need to keep the new datagram */
donatien 0:8e01dca41002 381 goto freepbuf;
donatien 0:8e01dca41002 382 #endif /* IP_REASS_CHECK_OVERLAP */
donatien 0:8e01dca41002 383 } else {
donatien 0:8e01dca41002 384 /* Check if the fragments received so far have no wholes. */
donatien 0:8e01dca41002 385 if (iprh_prev != NULL) {
donatien 0:8e01dca41002 386 if (iprh_prev->end != iprh_tmp->start) {
donatien 0:8e01dca41002 387 /* There is a fragment missing between the current
donatien 0:8e01dca41002 388 * and the previous fragment */
donatien 0:8e01dca41002 389 valid = 0;
donatien 0:8e01dca41002 390 }
donatien 0:8e01dca41002 391 }
donatien 0:8e01dca41002 392 }
donatien 0:8e01dca41002 393 q = iprh_tmp->next_pbuf;
donatien 0:8e01dca41002 394 iprh_prev = iprh_tmp;
donatien 0:8e01dca41002 395 }
donatien 0:8e01dca41002 396
donatien 0:8e01dca41002 397 /* If q is NULL, then we made it to the end of the list. Determine what to do now */
donatien 0:8e01dca41002 398 if (q == NULL) {
donatien 0:8e01dca41002 399 if (iprh_prev != NULL) {
donatien 0:8e01dca41002 400 /* this is (for now), the fragment with the highest offset:
donatien 0:8e01dca41002 401 * chain it to the last fragment */
donatien 0:8e01dca41002 402 #if IP_REASS_CHECK_OVERLAP
donatien 0:8e01dca41002 403 LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
donatien 0:8e01dca41002 404 #endif /* IP_REASS_CHECK_OVERLAP */
donatien 0:8e01dca41002 405 iprh_prev->next_pbuf = new_p;
donatien 0:8e01dca41002 406 if (iprh_prev->end != iprh->start) {
donatien 0:8e01dca41002 407 valid = 0;
donatien 0:8e01dca41002 408 }
donatien 0:8e01dca41002 409 } else {
donatien 0:8e01dca41002 410 #if IP_REASS_CHECK_OVERLAP
donatien 0:8e01dca41002 411 LWIP_ASSERT("no previous fragment, this must be the first fragment!",
donatien 0:8e01dca41002 412 ipr->p == NULL);
donatien 0:8e01dca41002 413 #endif /* IP_REASS_CHECK_OVERLAP */
donatien 0:8e01dca41002 414 /* this is the first fragment we ever received for this ip datagram */
donatien 0:8e01dca41002 415 ipr->p = new_p;
donatien 0:8e01dca41002 416 }
donatien 0:8e01dca41002 417 }
donatien 0:8e01dca41002 418
donatien 0:8e01dca41002 419 /* At this point, the validation part begins: */
donatien 0:8e01dca41002 420 /* If we already received the last fragment */
donatien 0:8e01dca41002 421 if ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0) {
donatien 0:8e01dca41002 422 /* and had no wholes so far */
donatien 0:8e01dca41002 423 if (valid) {
donatien 0:8e01dca41002 424 /* then check if the rest of the fragments is here */
donatien 0:8e01dca41002 425 /* Check if the queue starts with the first datagram */
donatien 0:8e01dca41002 426 if (((struct ip_reass_helper*)ipr->p->payload)->start != 0) {
donatien 0:8e01dca41002 427 valid = 0;
donatien 0:8e01dca41002 428 } else {
donatien 0:8e01dca41002 429 /* and check that there are no wholes after this datagram */
donatien 0:8e01dca41002 430 iprh_prev = iprh;
donatien 0:8e01dca41002 431 q = iprh->next_pbuf;
donatien 0:8e01dca41002 432 while (q != NULL) {
donatien 0:8e01dca41002 433 iprh = (struct ip_reass_helper*)q->payload;
donatien 0:8e01dca41002 434 if (iprh_prev->end != iprh->start) {
donatien 0:8e01dca41002 435 valid = 0;
donatien 0:8e01dca41002 436 break;
donatien 0:8e01dca41002 437 }
donatien 0:8e01dca41002 438 iprh_prev = iprh;
donatien 0:8e01dca41002 439 q = iprh->next_pbuf;
donatien 0:8e01dca41002 440 }
donatien 0:8e01dca41002 441 /* if still valid, all fragments are received
donatien 0:8e01dca41002 442 * (because to the MF==0 already arrived */
donatien 0:8e01dca41002 443 if (valid) {
donatien 0:8e01dca41002 444 LWIP_ASSERT("sanity check", ipr->p != NULL);
donatien 0:8e01dca41002 445 LWIP_ASSERT("sanity check",
donatien 0:8e01dca41002 446 ((struct ip_reass_helper*)ipr->p->payload) != iprh);
donatien 0:8e01dca41002 447 LWIP_ASSERT("validate_datagram:next_pbuf!=NULL",
donatien 0:8e01dca41002 448 iprh->next_pbuf == NULL);
donatien 0:8e01dca41002 449 LWIP_ASSERT("validate_datagram:datagram end!=datagram len",
donatien 0:8e01dca41002 450 iprh->end == ipr->datagram_len);
donatien 0:8e01dca41002 451 }
donatien 0:8e01dca41002 452 }
donatien 0:8e01dca41002 453 }
donatien 0:8e01dca41002 454 /* If valid is 0 here, there are some fragments missing in the middle
donatien 0:8e01dca41002 455 * (since MF == 0 has already arrived). Such datagrams simply time out if
donatien 0:8e01dca41002 456 * no more fragments are received... */
donatien 0:8e01dca41002 457 return valid;
donatien 0:8e01dca41002 458 }
donatien 0:8e01dca41002 459 /* If we come here, not all fragments were received, yet! */
donatien 0:8e01dca41002 460 return 0; /* not yet valid! */
donatien 0:8e01dca41002 461 #if IP_REASS_CHECK_OVERLAP
donatien 0:8e01dca41002 462 freepbuf:
donatien 0:8e01dca41002 463 ip_reass_pbufcount -= pbuf_clen(new_p);
donatien 0:8e01dca41002 464 pbuf_free(new_p);
donatien 0:8e01dca41002 465 return 0;
donatien 0:8e01dca41002 466 #endif /* IP_REASS_CHECK_OVERLAP */
donatien 0:8e01dca41002 467 }
donatien 0:8e01dca41002 468
donatien 0:8e01dca41002 469 /**
donatien 0:8e01dca41002 470 * Reassembles incoming IP fragments into an IP datagram.
donatien 0:8e01dca41002 471 *
donatien 0:8e01dca41002 472 * @param p points to a pbuf chain of the fragment
donatien 0:8e01dca41002 473 * @return NULL if reassembly is incomplete, ? otherwise
donatien 0:8e01dca41002 474 */
donatien 0:8e01dca41002 475 struct pbuf *
donatien 0:8e01dca41002 476 ip_reass(struct pbuf *p)
donatien 0:8e01dca41002 477 {
donatien 0:8e01dca41002 478 struct pbuf *r;
donatien 0:8e01dca41002 479 struct ip_hdr *fraghdr;
donatien 0:8e01dca41002 480 struct ip_reassdata *ipr;
donatien 0:8e01dca41002 481 struct ip_reass_helper *iprh;
donatien 0:8e01dca41002 482 u16_t offset, len;
donatien 0:8e01dca41002 483 u8_t clen;
donatien 0:8e01dca41002 484 struct ip_reassdata *ipr_prev = NULL;
donatien 0:8e01dca41002 485
donatien 0:8e01dca41002 486 IPFRAG_STATS_INC(ip_frag.recv);
donatien 0:8e01dca41002 487 snmp_inc_ipreasmreqds();
donatien 0:8e01dca41002 488
donatien 0:8e01dca41002 489 fraghdr = (struct ip_hdr*)p->payload;
donatien 0:8e01dca41002 490
donatien 0:8e01dca41002 491 if ((IPH_HL(fraghdr) * 4) != IP_HLEN) {
donatien 0:8e01dca41002 492 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n"));
donatien 0:8e01dca41002 493 IPFRAG_STATS_INC(ip_frag.err);
donatien 0:8e01dca41002 494 goto nullreturn;
donatien 0:8e01dca41002 495 }
donatien 0:8e01dca41002 496
donatien 0:8e01dca41002 497 offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
donatien 0:8e01dca41002 498 len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
donatien 0:8e01dca41002 499
donatien 0:8e01dca41002 500 /* Check if we are allowed to enqueue more datagrams. */
donatien 0:8e01dca41002 501 clen = pbuf_clen(p);
donatien 0:8e01dca41002 502 if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
donatien 0:8e01dca41002 503 #if IP_REASS_FREE_OLDEST
donatien 0:8e01dca41002 504 if (!ip_reass_remove_oldest_datagram(fraghdr, clen) ||
donatien 0:8e01dca41002 505 ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
donatien 0:8e01dca41002 506 #endif /* IP_REASS_FREE_OLDEST */
donatien 0:8e01dca41002 507 {
donatien 0:8e01dca41002 508 /* No datagram could be freed and still too many pbufs enqueued */
donatien 0:8e01dca41002 509 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
donatien 0:8e01dca41002 510 ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
donatien 0:8e01dca41002 511 IPFRAG_STATS_INC(ip_frag.memerr);
donatien 0:8e01dca41002 512 /* @todo: send ICMP time exceeded here? */
donatien 0:8e01dca41002 513 /* drop this pbuf */
donatien 0:8e01dca41002 514 goto nullreturn;
donatien 0:8e01dca41002 515 }
donatien 0:8e01dca41002 516 }
donatien 0:8e01dca41002 517
donatien 0:8e01dca41002 518 /* Look for the datagram the fragment belongs to in the current datagram queue,
donatien 0:8e01dca41002 519 * remembering the previous in the queue for later dequeueing. */
donatien 0:8e01dca41002 520 for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
donatien 0:8e01dca41002 521 /* Check if the incoming fragment matches the one currently present
donatien 0:8e01dca41002 522 in the reassembly buffer. If so, we proceed with copying the
donatien 0:8e01dca41002 523 fragment into the buffer. */
donatien 0:8e01dca41002 524 if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
donatien 0:8e01dca41002 525 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
donatien 0:8e01dca41002 526 ntohs(IPH_ID(fraghdr))));
donatien 0:8e01dca41002 527 IPFRAG_STATS_INC(ip_frag.cachehit);
donatien 0:8e01dca41002 528 break;
donatien 0:8e01dca41002 529 }
donatien 0:8e01dca41002 530 ipr_prev = ipr;
donatien 0:8e01dca41002 531 }
donatien 0:8e01dca41002 532
donatien 0:8e01dca41002 533 if (ipr == NULL) {
donatien 0:8e01dca41002 534 /* Enqueue a new datagram into the datagram queue */
donatien 0:8e01dca41002 535 ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
donatien 0:8e01dca41002 536 /* Bail if unable to enqueue */
donatien 0:8e01dca41002 537 if(ipr == NULL) {
donatien 0:8e01dca41002 538 goto nullreturn;
donatien 0:8e01dca41002 539 }
donatien 0:8e01dca41002 540 } else {
donatien 0:8e01dca41002 541 if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) &&
donatien 0:8e01dca41002 542 ((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
donatien 0:8e01dca41002 543 /* ipr->iphdr is not the header from the first fragment, but fraghdr is
donatien 0:8e01dca41002 544 * -> copy fraghdr into ipr->iphdr since we want to have the header
donatien 0:8e01dca41002 545 * of the first fragment (for ICMP time exceeded and later, for copying
donatien 0:8e01dca41002 546 * all options, if supported)*/
donatien 0:8e01dca41002 547 SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
donatien 0:8e01dca41002 548 }
donatien 0:8e01dca41002 549 }
donatien 0:8e01dca41002 550 /* Track the current number of pbufs current 'in-flight', in order to limit
donatien 0:8e01dca41002 551 the number of fragments that may be enqueued at any one time */
donatien 0:8e01dca41002 552 ip_reass_pbufcount += clen;
donatien 0:8e01dca41002 553
donatien 0:8e01dca41002 554 /* At this point, we have either created a new entry or pointing
donatien 0:8e01dca41002 555 * to an existing one */
donatien 0:8e01dca41002 556
donatien 0:8e01dca41002 557 /* check for 'no more fragments', and update queue entry*/
donatien 0:8e01dca41002 558 if ((IPH_OFFSET(fraghdr) & PP_NTOHS(IP_MF)) == 0) {
donatien 0:8e01dca41002 559 ipr->flags |= IP_REASS_FLAG_LASTFRAG;
donatien 0:8e01dca41002 560 ipr->datagram_len = offset + len;
donatien 0:8e01dca41002 561 LWIP_DEBUGF(IP_REASS_DEBUG,
donatien 0:8e01dca41002 562 ("ip_reass: last fragment seen, total len %"S16_F"\n",
donatien 0:8e01dca41002 563 ipr->datagram_len));
donatien 0:8e01dca41002 564 }
donatien 0:8e01dca41002 565 /* find the right place to insert this pbuf */
donatien 0:8e01dca41002 566 /* @todo: trim pbufs if fragments are overlapping */
donatien 0:8e01dca41002 567 if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) {
donatien 0:8e01dca41002 568 /* the totally last fragment (flag more fragments = 0) was received at least
donatien 0:8e01dca41002 569 * once AND all fragments are received */
donatien 0:8e01dca41002 570 ipr->datagram_len += IP_HLEN;
donatien 0:8e01dca41002 571
donatien 0:8e01dca41002 572 /* save the second pbuf before copying the header over the pointer */
donatien 0:8e01dca41002 573 r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf;
donatien 0:8e01dca41002 574
donatien 0:8e01dca41002 575 /* copy the original ip header back to the first pbuf */
donatien 0:8e01dca41002 576 fraghdr = (struct ip_hdr*)(ipr->p->payload);
donatien 0:8e01dca41002 577 SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
donatien 0:8e01dca41002 578 IPH_LEN_SET(fraghdr, htons(ipr->datagram_len));
donatien 0:8e01dca41002 579 IPH_OFFSET_SET(fraghdr, 0);
donatien 0:8e01dca41002 580 IPH_CHKSUM_SET(fraghdr, 0);
donatien 0:8e01dca41002 581 /* @todo: do we need to set calculate the correct checksum? */
donatien 0:8e01dca41002 582 IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));
donatien 0:8e01dca41002 583
donatien 0:8e01dca41002 584 p = ipr->p;
donatien 0:8e01dca41002 585
donatien 0:8e01dca41002 586 /* chain together the pbufs contained within the reass_data list. */
donatien 0:8e01dca41002 587 while(r != NULL) {
donatien 0:8e01dca41002 588 iprh = (struct ip_reass_helper*)r->payload;
donatien 0:8e01dca41002 589
donatien 0:8e01dca41002 590 /* hide the ip header for every succeding fragment */
donatien 0:8e01dca41002 591 pbuf_header(r, -IP_HLEN);
donatien 0:8e01dca41002 592 pbuf_cat(p, r);
donatien 0:8e01dca41002 593 r = iprh->next_pbuf;
donatien 0:8e01dca41002 594 }
donatien 0:8e01dca41002 595 /* release the sources allocate for the fragment queue entry */
donatien 0:8e01dca41002 596 ip_reass_dequeue_datagram(ipr, ipr_prev);
donatien 0:8e01dca41002 597
donatien 0:8e01dca41002 598 /* and adjust the number of pbufs currently queued for reassembly. */
donatien 0:8e01dca41002 599 ip_reass_pbufcount -= pbuf_clen(p);
donatien 0:8e01dca41002 600
donatien 0:8e01dca41002 601 /* Return the pbuf chain */
donatien 0:8e01dca41002 602 return p;
donatien 0:8e01dca41002 603 }
donatien 0:8e01dca41002 604 /* the datagram is not (yet?) reassembled completely */
donatien 0:8e01dca41002 605 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
donatien 0:8e01dca41002 606 return NULL;
donatien 0:8e01dca41002 607
donatien 0:8e01dca41002 608 nullreturn:
donatien 0:8e01dca41002 609 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n"));
donatien 0:8e01dca41002 610 IPFRAG_STATS_INC(ip_frag.drop);
donatien 0:8e01dca41002 611 pbuf_free(p);
donatien 0:8e01dca41002 612 return NULL;
donatien 0:8e01dca41002 613 }
donatien 0:8e01dca41002 614 #endif /* IP_REASSEMBLY */
donatien 0:8e01dca41002 615
donatien 0:8e01dca41002 616 #if IP_FRAG
donatien 0:8e01dca41002 617 #if IP_FRAG_USES_STATIC_BUF
donatien 0:8e01dca41002 618 static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU + MEM_ALIGNMENT - 1)];
donatien 0:8e01dca41002 619 #else /* IP_FRAG_USES_STATIC_BUF */
donatien 0:8e01dca41002 620
donatien 0:8e01dca41002 621 #if !LWIP_NETIF_TX_SINGLE_PBUF
donatien 0:8e01dca41002 622 /** Allocate a new struct pbuf_custom_ref */
donatien 0:8e01dca41002 623 static struct pbuf_custom_ref*
donatien 0:8e01dca41002 624 ip_frag_alloc_pbuf_custom_ref(void)
donatien 0:8e01dca41002 625 {
donatien 0:8e01dca41002 626 return (struct pbuf_custom_ref*)memp_malloc(MEMP_FRAG_PBUF);
donatien 0:8e01dca41002 627 }
donatien 0:8e01dca41002 628
donatien 0:8e01dca41002 629 /** Free a struct pbuf_custom_ref */
donatien 0:8e01dca41002 630 static void
donatien 0:8e01dca41002 631 ip_frag_free_pbuf_custom_ref(struct pbuf_custom_ref* p)
donatien 0:8e01dca41002 632 {
donatien 0:8e01dca41002 633 LWIP_ASSERT("p != NULL", p != NULL);
donatien 0:8e01dca41002 634 memp_free(MEMP_FRAG_PBUF, p);
donatien 0:8e01dca41002 635 }
donatien 0:8e01dca41002 636
donatien 0:8e01dca41002 637 /** Free-callback function to free a 'struct pbuf_custom_ref', called by
donatien 0:8e01dca41002 638 * pbuf_free. */
donatien 0:8e01dca41002 639 static void
donatien 0:8e01dca41002 640 ipfrag_free_pbuf_custom(struct pbuf *p)
donatien 0:8e01dca41002 641 {
donatien 0:8e01dca41002 642 struct pbuf_custom_ref *pcr = (struct pbuf_custom_ref*)p;
donatien 0:8e01dca41002 643 LWIP_ASSERT("pcr != NULL", pcr != NULL);
donatien 0:8e01dca41002 644 LWIP_ASSERT("pcr == p", (void*)pcr == (void*)p);
donatien 0:8e01dca41002 645 if (pcr->original != NULL) {
donatien 0:8e01dca41002 646 pbuf_free(pcr->original);
donatien 0:8e01dca41002 647 }
donatien 0:8e01dca41002 648 ip_frag_free_pbuf_custom_ref(pcr);
donatien 0:8e01dca41002 649 }
donatien 0:8e01dca41002 650 #endif /* !LWIP_NETIF_TX_SINGLE_PBUF */
donatien 0:8e01dca41002 651 #endif /* IP_FRAG_USES_STATIC_BUF */
donatien 0:8e01dca41002 652
donatien 0:8e01dca41002 653 /**
donatien 0:8e01dca41002 654 * Fragment an IP datagram if too large for the netif.
donatien 0:8e01dca41002 655 *
donatien 0:8e01dca41002 656 * Chop the datagram in MTU sized chunks and send them in order
donatien 0:8e01dca41002 657 * by using a fixed size static memory buffer (PBUF_REF) or
donatien 0:8e01dca41002 658 * point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF).
donatien 0:8e01dca41002 659 *
donatien 0:8e01dca41002 660 * @param p ip packet to send
donatien 0:8e01dca41002 661 * @param netif the netif on which to send
donatien 0:8e01dca41002 662 * @param dest destination ip address to which to send
donatien 0:8e01dca41002 663 *
donatien 0:8e01dca41002 664 * @return ERR_OK if sent successfully, err_t otherwise
donatien 0:8e01dca41002 665 */
donatien 0:8e01dca41002 666 err_t
donatien 0:8e01dca41002 667 ip_frag(struct pbuf *p, struct netif *netif, ip_addr_t *dest)
donatien 0:8e01dca41002 668 {
donatien 0:8e01dca41002 669 struct pbuf *rambuf;
donatien 0:8e01dca41002 670 #if IP_FRAG_USES_STATIC_BUF
donatien 0:8e01dca41002 671 struct pbuf *header;
donatien 0:8e01dca41002 672 #else
donatien 0:8e01dca41002 673 #if !LWIP_NETIF_TX_SINGLE_PBUF
donatien 0:8e01dca41002 674 struct pbuf *newpbuf;
donatien 0:8e01dca41002 675 #endif
donatien 0:8e01dca41002 676 struct ip_hdr *original_iphdr;
donatien 0:8e01dca41002 677 #endif
donatien 0:8e01dca41002 678 struct ip_hdr *iphdr;
donatien 0:8e01dca41002 679 u16_t nfb;
donatien 0:8e01dca41002 680 u16_t left, cop;
donatien 0:8e01dca41002 681 u16_t mtu = netif->mtu;
donatien 0:8e01dca41002 682 u16_t ofo, omf;
donatien 0:8e01dca41002 683 u16_t last;
donatien 0:8e01dca41002 684 u16_t poff = IP_HLEN;
donatien 0:8e01dca41002 685 u16_t tmp;
donatien 0:8e01dca41002 686 #if !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF
donatien 0:8e01dca41002 687 u16_t newpbuflen = 0;
donatien 0:8e01dca41002 688 u16_t left_to_copy;
donatien 0:8e01dca41002 689 #endif
donatien 0:8e01dca41002 690
donatien 0:8e01dca41002 691 /* Get a RAM based MTU sized pbuf */
donatien 0:8e01dca41002 692 #if IP_FRAG_USES_STATIC_BUF
donatien 0:8e01dca41002 693 /* When using a static buffer, we use a PBUF_REF, which we will
donatien 0:8e01dca41002 694 * use to reference the packet (without link header).
donatien 0:8e01dca41002 695 * Layer and length is irrelevant.
donatien 0:8e01dca41002 696 */
donatien 0:8e01dca41002 697 rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
donatien 0:8e01dca41002 698 if (rambuf == NULL) {
donatien 0:8e01dca41002 699 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n"));
donatien 0:8e01dca41002 700 return ERR_MEM;
donatien 0:8e01dca41002 701 }
donatien 0:8e01dca41002 702 rambuf->tot_len = rambuf->len = mtu;
donatien 0:8e01dca41002 703 rambuf->payload = LWIP_MEM_ALIGN((void *)buf);
donatien 0:8e01dca41002 704
donatien 0:8e01dca41002 705 /* Copy the IP header in it */
donatien 0:8e01dca41002 706 iphdr = (struct ip_hdr *)rambuf->payload;
donatien 0:8e01dca41002 707 SMEMCPY(iphdr, p->payload, IP_HLEN);
donatien 0:8e01dca41002 708 #else /* IP_FRAG_USES_STATIC_BUF */
donatien 0:8e01dca41002 709 original_iphdr = (struct ip_hdr *)p->payload;
donatien 0:8e01dca41002 710 iphdr = original_iphdr;
donatien 0:8e01dca41002 711 #endif /* IP_FRAG_USES_STATIC_BUF */
donatien 0:8e01dca41002 712
donatien 0:8e01dca41002 713 /* Save original offset */
donatien 0:8e01dca41002 714 tmp = ntohs(IPH_OFFSET(iphdr));
donatien 0:8e01dca41002 715 ofo = tmp & IP_OFFMASK;
donatien 0:8e01dca41002 716 omf = tmp & IP_MF;
donatien 0:8e01dca41002 717
donatien 0:8e01dca41002 718 left = p->tot_len - IP_HLEN;
donatien 0:8e01dca41002 719
donatien 0:8e01dca41002 720 nfb = (mtu - IP_HLEN) / 8;
donatien 0:8e01dca41002 721
donatien 0:8e01dca41002 722 while (left) {
donatien 0:8e01dca41002 723 last = (left <= mtu - IP_HLEN);
donatien 0:8e01dca41002 724
donatien 0:8e01dca41002 725 /* Set new offset and MF flag */
donatien 0:8e01dca41002 726 tmp = omf | (IP_OFFMASK & (ofo));
donatien 0:8e01dca41002 727 if (!last) {
donatien 0:8e01dca41002 728 tmp = tmp | IP_MF;
donatien 0:8e01dca41002 729 }
donatien 0:8e01dca41002 730
donatien 0:8e01dca41002 731 /* Fill this fragment */
donatien 0:8e01dca41002 732 cop = last ? left : nfb * 8;
donatien 0:8e01dca41002 733
donatien 0:8e01dca41002 734 #if IP_FRAG_USES_STATIC_BUF
donatien 0:8e01dca41002 735 poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
donatien 0:8e01dca41002 736 #else /* IP_FRAG_USES_STATIC_BUF */
donatien 0:8e01dca41002 737 #if LWIP_NETIF_TX_SINGLE_PBUF
donatien 0:8e01dca41002 738 rambuf = pbuf_alloc(PBUF_IP, cop, PBUF_RAM);
donatien 0:8e01dca41002 739 if (rambuf == NULL) {
donatien 0:8e01dca41002 740 return ERR_MEM;
donatien 0:8e01dca41002 741 }
donatien 0:8e01dca41002 742 LWIP_ASSERT("this needs a pbuf in one piece!",
donatien 0:8e01dca41002 743 (rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
donatien 0:8e01dca41002 744 poff += pbuf_copy_partial(p, rambuf->payload, cop, poff);
donatien 0:8e01dca41002 745 /* make room for the IP header */
donatien 0:8e01dca41002 746 if(pbuf_header(rambuf, IP_HLEN)) {
donatien 0:8e01dca41002 747 pbuf_free(rambuf);
donatien 0:8e01dca41002 748 return ERR_MEM;
donatien 0:8e01dca41002 749 }
donatien 0:8e01dca41002 750 /* fill in the IP header */
donatien 0:8e01dca41002 751 SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
donatien 0:8e01dca41002 752 iphdr = rambuf->payload;
donatien 0:8e01dca41002 753 #else /* LWIP_NETIF_TX_SINGLE_PBUF */
donatien 0:8e01dca41002 754 /* When not using a static buffer, create a chain of pbufs.
donatien 0:8e01dca41002 755 * The first will be a PBUF_RAM holding the link and IP header.
donatien 0:8e01dca41002 756 * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
donatien 0:8e01dca41002 757 * but limited to the size of an mtu.
donatien 0:8e01dca41002 758 */
donatien 0:8e01dca41002 759 rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
donatien 0:8e01dca41002 760 if (rambuf == NULL) {
donatien 0:8e01dca41002 761 return ERR_MEM;
donatien 0:8e01dca41002 762 }
donatien 0:8e01dca41002 763 LWIP_ASSERT("this needs a pbuf in one piece!",
donatien 0:8e01dca41002 764 (p->len >= (IP_HLEN)));
donatien 0:8e01dca41002 765 SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
donatien 0:8e01dca41002 766 iphdr = (struct ip_hdr *)rambuf->payload;
donatien 0:8e01dca41002 767
donatien 0:8e01dca41002 768 /* Can just adjust p directly for needed offset. */
donatien 0:8e01dca41002 769 p->payload = (u8_t *)p->payload + poff;
donatien 0:8e01dca41002 770 p->len -= poff;
donatien 0:8e01dca41002 771
donatien 0:8e01dca41002 772 left_to_copy = cop;
donatien 0:8e01dca41002 773 while (left_to_copy) {
donatien 0:8e01dca41002 774 struct pbuf_custom_ref *pcr;
donatien 0:8e01dca41002 775 newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
donatien 0:8e01dca41002 776 /* Is this pbuf already empty? */
donatien 0:8e01dca41002 777 if (!newpbuflen) {
donatien 0:8e01dca41002 778 p = p->next;
donatien 0:8e01dca41002 779 continue;
donatien 0:8e01dca41002 780 }
donatien 0:8e01dca41002 781 pcr = ip_frag_alloc_pbuf_custom_ref();
donatien 0:8e01dca41002 782 if (pcr == NULL) {
donatien 0:8e01dca41002 783 pbuf_free(rambuf);
donatien 0:8e01dca41002 784 return ERR_MEM;
donatien 0:8e01dca41002 785 }
donatien 0:8e01dca41002 786 /* Mirror this pbuf, although we might not need all of it. */
donatien 0:8e01dca41002 787 newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
donatien 0:8e01dca41002 788 if (newpbuf == NULL) {
donatien 0:8e01dca41002 789 ip_frag_free_pbuf_custom_ref(pcr);
donatien 0:8e01dca41002 790 pbuf_free(rambuf);
donatien 0:8e01dca41002 791 return ERR_MEM;
donatien 0:8e01dca41002 792 }
donatien 0:8e01dca41002 793 pbuf_ref(p);
donatien 0:8e01dca41002 794 pcr->original = p;
donatien 0:8e01dca41002 795 pcr->pc.custom_free_function = ipfrag_free_pbuf_custom;
donatien 0:8e01dca41002 796
donatien 0:8e01dca41002 797 /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
donatien 0:8e01dca41002 798 * so that it is removed when pbuf_dechain is later called on rambuf.
donatien 0:8e01dca41002 799 */
donatien 0:8e01dca41002 800 pbuf_cat(rambuf, newpbuf);
donatien 0:8e01dca41002 801 left_to_copy -= newpbuflen;
donatien 0:8e01dca41002 802 if (left_to_copy) {
donatien 0:8e01dca41002 803 p = p->next;
donatien 0:8e01dca41002 804 }
donatien 0:8e01dca41002 805 }
donatien 0:8e01dca41002 806 poff = newpbuflen;
donatien 0:8e01dca41002 807 #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
donatien 0:8e01dca41002 808 #endif /* IP_FRAG_USES_STATIC_BUF */
donatien 0:8e01dca41002 809
donatien 0:8e01dca41002 810 /* Correct header */
donatien 0:8e01dca41002 811 IPH_OFFSET_SET(iphdr, htons(tmp));
donatien 0:8e01dca41002 812 IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
donatien 0:8e01dca41002 813 IPH_CHKSUM_SET(iphdr, 0);
donatien 0:8e01dca41002 814 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
donatien 0:8e01dca41002 815
donatien 0:8e01dca41002 816 #if IP_FRAG_USES_STATIC_BUF
donatien 0:8e01dca41002 817 if (last) {
donatien 0:8e01dca41002 818 pbuf_realloc(rambuf, left + IP_HLEN);
donatien 0:8e01dca41002 819 }
donatien 0:8e01dca41002 820
donatien 0:8e01dca41002 821 /* This part is ugly: we alloc a RAM based pbuf for
donatien 0:8e01dca41002 822 * the link level header for each chunk and then
donatien 0:8e01dca41002 823 * free it.A PBUF_ROM style pbuf for which pbuf_header
donatien 0:8e01dca41002 824 * worked would make things simpler.
donatien 0:8e01dca41002 825 */
donatien 0:8e01dca41002 826 header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
donatien 0:8e01dca41002 827 if (header != NULL) {
donatien 0:8e01dca41002 828 pbuf_chain(header, rambuf);
donatien 0:8e01dca41002 829 netif->output(netif, header, dest);
donatien 0:8e01dca41002 830 IPFRAG_STATS_INC(ip_frag.xmit);
donatien 0:8e01dca41002 831 snmp_inc_ipfragcreates();
donatien 0:8e01dca41002 832 pbuf_free(header);
donatien 0:8e01dca41002 833 } else {
donatien 0:8e01dca41002 834 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
donatien 0:8e01dca41002 835 pbuf_free(rambuf);
donatien 0:8e01dca41002 836 return ERR_MEM;
donatien 0:8e01dca41002 837 }
donatien 0:8e01dca41002 838 #else /* IP_FRAG_USES_STATIC_BUF */
donatien 0:8e01dca41002 839 /* No need for separate header pbuf - we allowed room for it in rambuf
donatien 0:8e01dca41002 840 * when allocated.
donatien 0:8e01dca41002 841 */
donatien 0:8e01dca41002 842 netif->output(netif, rambuf, dest);
donatien 0:8e01dca41002 843 IPFRAG_STATS_INC(ip_frag.xmit);
donatien 0:8e01dca41002 844
donatien 0:8e01dca41002 845 /* Unfortunately we can't reuse rambuf - the hardware may still be
donatien 0:8e01dca41002 846 * using the buffer. Instead we free it (and the ensuing chain) and
donatien 0:8e01dca41002 847 * recreate it next time round the loop. If we're lucky the hardware
donatien 0:8e01dca41002 848 * will have already sent the packet, the free will really free, and
donatien 0:8e01dca41002 849 * there will be zero memory penalty.
donatien 0:8e01dca41002 850 */
donatien 0:8e01dca41002 851
donatien 0:8e01dca41002 852 pbuf_free(rambuf);
donatien 0:8e01dca41002 853 #endif /* IP_FRAG_USES_STATIC_BUF */
donatien 0:8e01dca41002 854 left -= cop;
donatien 0:8e01dca41002 855 ofo += nfb;
donatien 0:8e01dca41002 856 }
donatien 0:8e01dca41002 857 #if IP_FRAG_USES_STATIC_BUF
donatien 0:8e01dca41002 858 pbuf_free(rambuf);
donatien 0:8e01dca41002 859 #endif /* IP_FRAG_USES_STATIC_BUF */
donatien 0:8e01dca41002 860 snmp_inc_ipfragoks();
donatien 0:8e01dca41002 861 return ERR_OK;
donatien 0:8e01dca41002 862 }
donatien 0:8e01dca41002 863 #endif /* IP_FRAG */