mbed unsupported / lwip

A version of LWIP, provided for backwards compatibility.

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trunk/Core/lwIP/core/ipv4/ip_frag.c@0:5e1631496985, 2012-05-08 (annotated)

Committer:
root@mbed.org
Date:
Tue May 08 15:32:10 2012 +0100
Revision:
0:5e1631496985
initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
root@mbed.org 0:5e1631496985 1 /**
root@mbed.org 0:5e1631496985 2 * @file
root@mbed.org 0:5e1631496985 3 * This is the IPv4 packet segmentation and reassembly implementation.
root@mbed.org 0:5e1631496985 4 *
root@mbed.org 0:5e1631496985 5 */
root@mbed.org 0:5e1631496985 6
root@mbed.org 0:5e1631496985 7 /*
root@mbed.org 0:5e1631496985 8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
root@mbed.org 0:5e1631496985 9 * All rights reserved.
root@mbed.org 0:5e1631496985 10 *
root@mbed.org 0:5e1631496985 11 * Redistribution and use in source and binary forms, with or without modification,
root@mbed.org 0:5e1631496985 12 * are permitted provided that the following conditions are met:
root@mbed.org 0:5e1631496985 13 *
root@mbed.org 0:5e1631496985 14 * 1. Redistributions of source code must retain the above copyright notice,
root@mbed.org 0:5e1631496985 15 * this list of conditions and the following disclaimer.
root@mbed.org 0:5e1631496985 16 * 2. Redistributions in binary form must reproduce the above copyright notice,
root@mbed.org 0:5e1631496985 17 * this list of conditions and the following disclaimer in the documentation
root@mbed.org 0:5e1631496985 18 * and/or other materials provided with the distribution.
root@mbed.org 0:5e1631496985 19 * 3. The name of the author may not be used to endorse or promote products
root@mbed.org 0:5e1631496985 20 * derived from this software without specific prior written permission.
root@mbed.org 0:5e1631496985 21 *
root@mbed.org 0:5e1631496985 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
root@mbed.org 0:5e1631496985 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
root@mbed.org 0:5e1631496985 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
root@mbed.org 0:5e1631496985 25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
root@mbed.org 0:5e1631496985 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
root@mbed.org 0:5e1631496985 27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
root@mbed.org 0:5e1631496985 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
root@mbed.org 0:5e1631496985 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
root@mbed.org 0:5e1631496985 30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
root@mbed.org 0:5e1631496985 31 * OF SUCH DAMAGE.
root@mbed.org 0:5e1631496985 32 *
root@mbed.org 0:5e1631496985 33 * This file is part of the lwIP TCP/IP stack.
root@mbed.org 0:5e1631496985 34 *
root@mbed.org 0:5e1631496985 35 * Author: Jani Monoses <jani@iv.ro>
root@mbed.org 0:5e1631496985 36 * Simon Goldschmidt
root@mbed.org 0:5e1631496985 37 * original reassembly code by Adam Dunkels <adam@sics.se>
root@mbed.org 0:5e1631496985 38 *
root@mbed.org 0:5e1631496985 39 */
root@mbed.org 0:5e1631496985 40
root@mbed.org 0:5e1631496985 41 #include "lwip/opt.h"
root@mbed.org 0:5e1631496985 42 #include "lwip/ip_frag.h"
root@mbed.org 0:5e1631496985 43 #include "lwip/ip.h"
root@mbed.org 0:5e1631496985 44 #include "lwip/inet.h"
root@mbed.org 0:5e1631496985 45 #include "lwip/inet_chksum.h"
root@mbed.org 0:5e1631496985 46 #include "lwip/netif.h"
root@mbed.org 0:5e1631496985 47 #include "lwip/snmp.h"
root@mbed.org 0:5e1631496985 48 #include "lwip/stats.h"
root@mbed.org 0:5e1631496985 49 #include "lwip/icmp.h"
root@mbed.org 0:5e1631496985 50
root@mbed.org 0:5e1631496985 51 #include <string.h>
root@mbed.org 0:5e1631496985 52
root@mbed.org 0:5e1631496985 53 #if IP_REASSEMBLY
root@mbed.org 0:5e1631496985 54 /**
root@mbed.org 0:5e1631496985 55 * The IP reassembly code currently has the following limitations:
root@mbed.org 0:5e1631496985 56 * - IP header options are not supported
root@mbed.org 0:5e1631496985 57 * - fragments must not overlap (e.g. due to different routes),
root@mbed.org 0:5e1631496985 58 * currently, overlapping or duplicate fragments are thrown away
root@mbed.org 0:5e1631496985 59 * if IP_REASS_CHECK_OVERLAP=1 (the default)!
root@mbed.org 0:5e1631496985 60 *
root@mbed.org 0:5e1631496985 61 * @todo: work with IP header options
root@mbed.org 0:5e1631496985 62 */
root@mbed.org 0:5e1631496985 63
root@mbed.org 0:5e1631496985 64 /** Setting this to 0, you can turn off checking the fragments for overlapping
root@mbed.org 0:5e1631496985 65 * regions. The code gets a little smaller. Only use this if you know that
root@mbed.org 0:5e1631496985 66 * overlapping won't occur on your network! */
root@mbed.org 0:5e1631496985 67 #ifndef IP_REASS_CHECK_OVERLAP
root@mbed.org 0:5e1631496985 68 #define IP_REASS_CHECK_OVERLAP 1
root@mbed.org 0:5e1631496985 69 #endif /* IP_REASS_CHECK_OVERLAP */
root@mbed.org 0:5e1631496985 70
root@mbed.org 0:5e1631496985 71 /** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
root@mbed.org 0:5e1631496985 72 * full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
root@mbed.org 0:5e1631496985 73 * Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
root@mbed.org 0:5e1631496985 74 * is set to 1, so one datagram can be reassembled at a time, only. */
root@mbed.org 0:5e1631496985 75 #ifndef IP_REASS_FREE_OLDEST
root@mbed.org 0:5e1631496985 76 #define IP_REASS_FREE_OLDEST 1
root@mbed.org 0:5e1631496985 77 #endif /* IP_REASS_FREE_OLDEST */
root@mbed.org 0:5e1631496985 78
root@mbed.org 0:5e1631496985 79 #define IP_REASS_FLAG_LASTFRAG 0x01
root@mbed.org 0:5e1631496985 80
root@mbed.org 0:5e1631496985 81 /** This is a helper struct which holds the starting
root@mbed.org 0:5e1631496985 82 * offset and the ending offset of this fragment to
root@mbed.org 0:5e1631496985 83 * easily chain the fragments.
root@mbed.org 0:5e1631496985 84 * It has to be packed since it has to fit inside the IP header.
root@mbed.org 0:5e1631496985 85 */
root@mbed.org 0:5e1631496985 86 // XXX: For armcc
root@mbed.org 0:5e1631496985 87 struct ip_reass_helper {
root@mbed.org 0:5e1631496985 88 struct pbuf *next_pbuf;
root@mbed.org 0:5e1631496985 89 u16_t start;
root@mbed.org 0:5e1631496985 90 u16_t end;
root@mbed.org 0:5e1631496985 91 };
root@mbed.org 0:5e1631496985 92
root@mbed.org 0:5e1631496985 93 /*
root@mbed.org 0:5e1631496985 94 #ifdef PACK_STRUCT_USE_INCLUDES
root@mbed.org 0:5e1631496985 95 # include "arch/bpstruct.h"
root@mbed.org 0:5e1631496985 96 #endif
root@mbed.org 0:5e1631496985 97 PACK_STRUCT_BEGIN
root@mbed.org 0:5e1631496985 98 struct ip_reass_helper {
root@mbed.org 0:5e1631496985 99 PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
root@mbed.org 0:5e1631496985 100 PACK_STRUCT_FIELD(u16_t start);
root@mbed.org 0:5e1631496985 101 PACK_STRUCT_FIELD(u16_t end);
root@mbed.org 0:5e1631496985 102 } PACK_STRUCT_STRUCT;
root@mbed.org 0:5e1631496985 103 PACK_STRUCT_END
root@mbed.org 0:5e1631496985 104 #ifdef PACK_STRUCT_USE_INCLUDES
root@mbed.org 0:5e1631496985 105 # include "arch/epstruct.h"
root@mbed.org 0:5e1631496985 106 #endif
root@mbed.org 0:5e1631496985 107 */
root@mbed.org 0:5e1631496985 108 #define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB) \
root@mbed.org 0:5e1631496985 109 (ip_addr_cmp(&(iphdrA)->src, &(iphdrB)->src) && \
root@mbed.org 0:5e1631496985 110 ip_addr_cmp(&(iphdrA)->dest, &(iphdrB)->dest) && \
root@mbed.org 0:5e1631496985 111 IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0
root@mbed.org 0:5e1631496985 112
root@mbed.org 0:5e1631496985 113 /* global variables */
root@mbed.org 0:5e1631496985 114 static struct ip_reassdata *reassdatagrams;
root@mbed.org 0:5e1631496985 115 static u16_t ip_reass_pbufcount;
root@mbed.org 0:5e1631496985 116
root@mbed.org 0:5e1631496985 117 /* function prototypes */
root@mbed.org 0:5e1631496985 118 static void ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
root@mbed.org 0:5e1631496985 119 static int ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
root@mbed.org 0:5e1631496985 120
root@mbed.org 0:5e1631496985 121 /**
root@mbed.org 0:5e1631496985 122 * Reassembly timer base function
root@mbed.org 0:5e1631496985 123 * for both NO_SYS == 0 and 1 (!).
root@mbed.org 0:5e1631496985 124 *
root@mbed.org 0:5e1631496985 125 * Should be called every 1000 msec (defined by IP_TMR_INTERVAL).
root@mbed.org 0:5e1631496985 126 */
root@mbed.org 0:5e1631496985 127 void
root@mbed.org 0:5e1631496985 128 ip_reass_tmr(void)
root@mbed.org 0:5e1631496985 129 {
root@mbed.org 0:5e1631496985 130 struct ip_reassdata *r, *prev = NULL;
root@mbed.org 0:5e1631496985 131
root@mbed.org 0:5e1631496985 132 r = reassdatagrams;
root@mbed.org 0:5e1631496985 133 while (r != NULL) {
root@mbed.org 0:5e1631496985 134 /* Decrement the timer. Once it reaches 0,
root@mbed.org 0:5e1631496985 135 * clean up the incomplete fragment assembly */
root@mbed.org 0:5e1631496985 136 if (r->timer > 0) {
root@mbed.org 0:5e1631496985 137 r->timer--;
root@mbed.org 0:5e1631496985 138 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)r->timer));
root@mbed.org 0:5e1631496985 139 prev = r;
root@mbed.org 0:5e1631496985 140 r = r->next;
root@mbed.org 0:5e1631496985 141 } else {
root@mbed.org 0:5e1631496985 142 /* reassembly timed out */
root@mbed.org 0:5e1631496985 143 struct ip_reassdata *tmp;
root@mbed.org 0:5e1631496985 144 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out\n"));
root@mbed.org 0:5e1631496985 145 tmp = r;
root@mbed.org 0:5e1631496985 146 /* get the next pointer before freeing */
root@mbed.org 0:5e1631496985 147 r = r->next;
root@mbed.org 0:5e1631496985 148 /* free the helper struct and all enqueued pbufs */
root@mbed.org 0:5e1631496985 149 ip_reass_free_complete_datagram(tmp, prev);
root@mbed.org 0:5e1631496985 150 }
root@mbed.org 0:5e1631496985 151 }
root@mbed.org 0:5e1631496985 152 }
root@mbed.org 0:5e1631496985 153
root@mbed.org 0:5e1631496985 154 /**
root@mbed.org 0:5e1631496985 155 * Free a datagram (struct ip_reassdata) and all its pbufs.
root@mbed.org 0:5e1631496985 156 * Updates the total count of enqueued pbufs (ip_reass_pbufcount),
root@mbed.org 0:5e1631496985 157 * SNMP counters and sends an ICMP time exceeded packet.
root@mbed.org 0:5e1631496985 158 *
root@mbed.org 0:5e1631496985 159 * @param ipr datagram to free
root@mbed.org 0:5e1631496985 160 * @param prev the previous datagram in the linked list
root@mbed.org 0:5e1631496985 161 * @return the number of pbufs freed
root@mbed.org 0:5e1631496985 162 */
root@mbed.org 0:5e1631496985 163 static int
root@mbed.org 0:5e1631496985 164 ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
root@mbed.org 0:5e1631496985 165 {
root@mbed.org 0:5e1631496985 166 int pbufs_freed = 0;
root@mbed.org 0:5e1631496985 167 struct pbuf *p;
root@mbed.org 0:5e1631496985 168 struct ip_reass_helper *iprh;
root@mbed.org 0:5e1631496985 169
root@mbed.org 0:5e1631496985 170 LWIP_ASSERT("prev != ipr", prev != ipr);
root@mbed.org 0:5e1631496985 171 if (prev != NULL) {
root@mbed.org 0:5e1631496985 172 LWIP_ASSERT("prev->next == ipr", prev->next == ipr);
root@mbed.org 0:5e1631496985 173 }
root@mbed.org 0:5e1631496985 174
root@mbed.org 0:5e1631496985 175 snmp_inc_ipreasmfails();
root@mbed.org 0:5e1631496985 176 #if LWIP_ICMP
root@mbed.org 0:5e1631496985 177 iprh = (struct ip_reass_helper *)ipr->p->payload;
root@mbed.org 0:5e1631496985 178 if (iprh->start == 0) {
root@mbed.org 0:5e1631496985 179 /* The first fragment was received, send ICMP time exceeded. */
root@mbed.org 0:5e1631496985 180 /* First, de-queue the first pbuf from r->p. */
root@mbed.org 0:5e1631496985 181 p = ipr->p;
root@mbed.org 0:5e1631496985 182 ipr->p = iprh->next_pbuf;
root@mbed.org 0:5e1631496985 183 /* Then, copy the original header into it. */
root@mbed.org 0:5e1631496985 184 SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN);
root@mbed.org 0:5e1631496985 185 icmp_time_exceeded(p, ICMP_TE_FRAG);
root@mbed.org 0:5e1631496985 186 pbufs_freed += pbuf_clen(p);
root@mbed.org 0:5e1631496985 187 pbuf_free(p);
root@mbed.org 0:5e1631496985 188 }
root@mbed.org 0:5e1631496985 189 #endif /* LWIP_ICMP */
root@mbed.org 0:5e1631496985 190
root@mbed.org 0:5e1631496985 191 /* First, free all received pbufs. The individual pbufs need to be released
root@mbed.org 0:5e1631496985 192 separately as they have not yet been chained */
root@mbed.org 0:5e1631496985 193 p = ipr->p;
root@mbed.org 0:5e1631496985 194 while (p != NULL) {
root@mbed.org 0:5e1631496985 195 struct pbuf *pcur;
root@mbed.org 0:5e1631496985 196 iprh = (struct ip_reass_helper *)p->payload;
root@mbed.org 0:5e1631496985 197 pcur = p;
root@mbed.org 0:5e1631496985 198 /* get the next pointer before freeing */
root@mbed.org 0:5e1631496985 199 p = iprh->next_pbuf;
root@mbed.org 0:5e1631496985 200 pbufs_freed += pbuf_clen(pcur);
root@mbed.org 0:5e1631496985 201 pbuf_free(pcur);
root@mbed.org 0:5e1631496985 202 }
root@mbed.org 0:5e1631496985 203 /* Then, unchain the struct ip_reassdata from the list and free it. */
root@mbed.org 0:5e1631496985 204 ip_reass_dequeue_datagram(ipr, prev);
root@mbed.org 0:5e1631496985 205 LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= pbufs_freed);
root@mbed.org 0:5e1631496985 206 ip_reass_pbufcount -= pbufs_freed;
root@mbed.org 0:5e1631496985 207
root@mbed.org 0:5e1631496985 208 return pbufs_freed;
root@mbed.org 0:5e1631496985 209 }
root@mbed.org 0:5e1631496985 210
root@mbed.org 0:5e1631496985 211 #if IP_REASS_FREE_OLDEST
root@mbed.org 0:5e1631496985 212 /**
root@mbed.org 0:5e1631496985 213 * Free the oldest datagram to make room for enqueueing new fragments.
root@mbed.org 0:5e1631496985 214 * The datagram 'fraghdr' belongs to is not freed!
root@mbed.org 0:5e1631496985 215 *
root@mbed.org 0:5e1631496985 216 * @param fraghdr IP header of the current fragment
root@mbed.org 0:5e1631496985 217 * @param pbufs_needed number of pbufs needed to enqueue
root@mbed.org 0:5e1631496985 218 * (used for freeing other datagrams if not enough space)
root@mbed.org 0:5e1631496985 219 * @return the number of pbufs freed
root@mbed.org 0:5e1631496985 220 */
root@mbed.org 0:5e1631496985 221 static int
root@mbed.org 0:5e1631496985 222 ip_reass_remove_oldest_datagram(struct ip_hdr *fraghdr, int pbufs_needed)
root@mbed.org 0:5e1631496985 223 {
root@mbed.org 0:5e1631496985 224 /* @todo Can't we simply remove the last datagram in the
root@mbed.org 0:5e1631496985 225 * linked list behind reassdatagrams?
root@mbed.org 0:5e1631496985 226 */
root@mbed.org 0:5e1631496985 227 struct ip_reassdata *r, *oldest, *prev;
root@mbed.org 0:5e1631496985 228 int pbufs_freed = 0, pbufs_freed_current;
root@mbed.org 0:5e1631496985 229 int other_datagrams;
root@mbed.org 0:5e1631496985 230
root@mbed.org 0:5e1631496985 231 /* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
root@mbed.org 0:5e1631496985 232 * but don't free the datagram that 'fraghdr' belongs to! */
root@mbed.org 0:5e1631496985 233 do {
root@mbed.org 0:5e1631496985 234 oldest = NULL;
root@mbed.org 0:5e1631496985 235 prev = NULL;
root@mbed.org 0:5e1631496985 236 other_datagrams = 0;
root@mbed.org 0:5e1631496985 237 r = reassdatagrams;
root@mbed.org 0:5e1631496985 238 while (r != NULL) {
root@mbed.org 0:5e1631496985 239 if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) {
root@mbed.org 0:5e1631496985 240 /* Not the same datagram as fraghdr */
root@mbed.org 0:5e1631496985 241 other_datagrams++;
root@mbed.org 0:5e1631496985 242 if (oldest == NULL) {
root@mbed.org 0:5e1631496985 243 oldest = r;
root@mbed.org 0:5e1631496985 244 } else if (r->timer <= oldest->timer) {
root@mbed.org 0:5e1631496985 245 /* older than the previous oldest */
root@mbed.org 0:5e1631496985 246 oldest = r;
root@mbed.org 0:5e1631496985 247 }
root@mbed.org 0:5e1631496985 248 }
root@mbed.org 0:5e1631496985 249 if (r->next != NULL) {
root@mbed.org 0:5e1631496985 250 prev = r;
root@mbed.org 0:5e1631496985 251 }
root@mbed.org 0:5e1631496985 252 r = r->next;
root@mbed.org 0:5e1631496985 253 }
root@mbed.org 0:5e1631496985 254 if (oldest != NULL) {
root@mbed.org 0:5e1631496985 255 pbufs_freed_current = ip_reass_free_complete_datagram(oldest, prev);
root@mbed.org 0:5e1631496985 256 pbufs_freed += pbufs_freed_current;
root@mbed.org 0:5e1631496985 257 }
root@mbed.org 0:5e1631496985 258 } while ((pbufs_freed < pbufs_needed) && (other_datagrams > 1));
root@mbed.org 0:5e1631496985 259 return pbufs_freed;
root@mbed.org 0:5e1631496985 260 }
root@mbed.org 0:5e1631496985 261 #endif /* IP_REASS_FREE_OLDEST */
root@mbed.org 0:5e1631496985 262
root@mbed.org 0:5e1631496985 263 /**
root@mbed.org 0:5e1631496985 264 * Enqueues a new fragment into the fragment queue
root@mbed.org 0:5e1631496985 265 * @param fraghdr points to the new fragments IP hdr
root@mbed.org 0:5e1631496985 266 * @param clen number of pbufs needed to enqueue (used for freeing other datagrams if not enough space)
root@mbed.org 0:5e1631496985 267 * @return A pointer to the queue location into which the fragment was enqueued
root@mbed.org 0:5e1631496985 268 */
root@mbed.org 0:5e1631496985 269 static struct ip_reassdata*
root@mbed.org 0:5e1631496985 270 ip_reass_enqueue_new_datagram(struct ip_hdr *fraghdr, int clen)
root@mbed.org 0:5e1631496985 271 {
root@mbed.org 0:5e1631496985 272 struct ip_reassdata* ipr;
root@mbed.org 0:5e1631496985 273 /* No matching previous fragment found, allocate a new reassdata struct */
root@mbed.org 0:5e1631496985 274 ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
root@mbed.org 0:5e1631496985 275 if (ipr == NULL) {
root@mbed.org 0:5e1631496985 276 #if IP_REASS_FREE_OLDEST
root@mbed.org 0:5e1631496985 277 if (ip_reass_remove_oldest_datagram(fraghdr, clen) >= clen) {
root@mbed.org 0:5e1631496985 278 ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
root@mbed.org 0:5e1631496985 279 }
root@mbed.org 0:5e1631496985 280 if (ipr == NULL)
root@mbed.org 0:5e1631496985 281 #endif /* IP_REASS_FREE_OLDEST */
root@mbed.org 0:5e1631496985 282 {
root@mbed.org 0:5e1631496985 283 IPFRAG_STATS_INC(ip_frag.memerr);
root@mbed.org 0:5e1631496985 284 LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct\n"));
root@mbed.org 0:5e1631496985 285 return NULL;
root@mbed.org 0:5e1631496985 286 }
root@mbed.org 0:5e1631496985 287 }
root@mbed.org 0:5e1631496985 288 memset(ipr, 0, sizeof(struct ip_reassdata));
root@mbed.org 0:5e1631496985 289 ipr->timer = IP_REASS_MAXAGE;
root@mbed.org 0:5e1631496985 290
root@mbed.org 0:5e1631496985 291 /* enqueue the new structure to the front of the list */
root@mbed.org 0:5e1631496985 292 ipr->next = reassdatagrams;
root@mbed.org 0:5e1631496985 293 reassdatagrams = ipr;
root@mbed.org 0:5e1631496985 294 /* copy the ip header for later tests and input */
root@mbed.org 0:5e1631496985 295 /* @todo: no ip options supported? */
root@mbed.org 0:5e1631496985 296 SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN);
root@mbed.org 0:5e1631496985 297 return ipr;
root@mbed.org 0:5e1631496985 298 }
root@mbed.org 0:5e1631496985 299
root@mbed.org 0:5e1631496985 300 /**
root@mbed.org 0:5e1631496985 301 * Dequeues a datagram from the datagram queue. Doesn't deallocate the pbufs.
root@mbed.org 0:5e1631496985 302 * @param ipr points to the queue entry to dequeue
root@mbed.org 0:5e1631496985 303 */
root@mbed.org 0:5e1631496985 304 static void
root@mbed.org 0:5e1631496985 305 ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
root@mbed.org 0:5e1631496985 306 {
root@mbed.org 0:5e1631496985 307
root@mbed.org 0:5e1631496985 308 /* dequeue the reass struct */
root@mbed.org 0:5e1631496985 309 if (reassdatagrams == ipr) {
root@mbed.org 0:5e1631496985 310 /* it was the first in the list */
root@mbed.org 0:5e1631496985 311 reassdatagrams = ipr->next;
root@mbed.org 0:5e1631496985 312 } else {
root@mbed.org 0:5e1631496985 313 /* it wasn't the first, so it must have a valid 'prev' */
root@mbed.org 0:5e1631496985 314 LWIP_ASSERT("sanity check linked list", prev != NULL);
root@mbed.org 0:5e1631496985 315 prev->next = ipr->next;
root@mbed.org 0:5e1631496985 316 }
root@mbed.org 0:5e1631496985 317
root@mbed.org 0:5e1631496985 318 /* now we can free the ip_reass struct */
root@mbed.org 0:5e1631496985 319 memp_free(MEMP_REASSDATA, ipr);
root@mbed.org 0:5e1631496985 320 }
root@mbed.org 0:5e1631496985 321
root@mbed.org 0:5e1631496985 322 /**
root@mbed.org 0:5e1631496985 323 * Chain a new pbuf into the pbuf list that composes the datagram. The pbuf list
root@mbed.org 0:5e1631496985 324 * will grow over time as new pbufs are rx.
root@mbed.org 0:5e1631496985 325 * Also checks that the datagram passes basic continuity checks (if the last
root@mbed.org 0:5e1631496985 326 * fragment was received at least once).
root@mbed.org 0:5e1631496985 327 * @param root_p points to the 'root' pbuf for the current datagram being assembled.
root@mbed.org 0:5e1631496985 328 * @param new_p points to the pbuf for the current fragment
root@mbed.org 0:5e1631496985 329 * @return 0 if invalid, >0 otherwise
root@mbed.org 0:5e1631496985 330 */
root@mbed.org 0:5e1631496985 331 static int
root@mbed.org 0:5e1631496985 332 ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata *ipr, struct pbuf *new_p)
root@mbed.org 0:5e1631496985 333 {
root@mbed.org 0:5e1631496985 334 struct ip_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
root@mbed.org 0:5e1631496985 335 struct pbuf *q;
root@mbed.org 0:5e1631496985 336 u16_t offset,len;
root@mbed.org 0:5e1631496985 337 struct ip_hdr *fraghdr;
root@mbed.org 0:5e1631496985 338 int valid = 1;
root@mbed.org 0:5e1631496985 339
root@mbed.org 0:5e1631496985 340 /* Extract length and fragment offset from current fragment */
root@mbed.org 0:5e1631496985 341 fraghdr = (struct ip_hdr*)new_p->payload;
root@mbed.org 0:5e1631496985 342 len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
root@mbed.org 0:5e1631496985 343 offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
root@mbed.org 0:5e1631496985 344
root@mbed.org 0:5e1631496985 345 /* overwrite the fragment's ip header from the pbuf with our helper struct,
root@mbed.org 0:5e1631496985 346 * and setup the embedded helper structure. */
root@mbed.org 0:5e1631496985 347 /* make sure the struct ip_reass_helper fits into the IP header */
root@mbed.org 0:5e1631496985 348 LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN",
root@mbed.org 0:5e1631496985 349 sizeof(struct ip_reass_helper) <= IP_HLEN);
root@mbed.org 0:5e1631496985 350 iprh = (struct ip_reass_helper*)new_p->payload;
root@mbed.org 0:5e1631496985 351 iprh->next_pbuf = NULL;
root@mbed.org 0:5e1631496985 352 iprh->start = offset;
root@mbed.org 0:5e1631496985 353 iprh->end = offset + len;
root@mbed.org 0:5e1631496985 354
root@mbed.org 0:5e1631496985 355 /* Iterate through until we either get to the end of the list (append),
root@mbed.org 0:5e1631496985 356 * or we find on with a larger offset (insert). */
root@mbed.org 0:5e1631496985 357 for (q = ipr->p; q != NULL;) {
root@mbed.org 0:5e1631496985 358 iprh_tmp = (struct ip_reass_helper*)q->payload;
root@mbed.org 0:5e1631496985 359 if (iprh->start < iprh_tmp->start) {
root@mbed.org 0:5e1631496985 360 /* the new pbuf should be inserted before this */
root@mbed.org 0:5e1631496985 361 iprh->next_pbuf = q;
root@mbed.org 0:5e1631496985 362 if (iprh_prev != NULL) {
root@mbed.org 0:5e1631496985 363 /* not the fragment with the lowest offset */
root@mbed.org 0:5e1631496985 364 #if IP_REASS_CHECK_OVERLAP
root@mbed.org 0:5e1631496985 365 if ((iprh->start < iprh_prev->end) || (iprh->end > iprh_tmp->start)) {
root@mbed.org 0:5e1631496985 366 /* fragment overlaps with previous or following, throw away */
root@mbed.org 0:5e1631496985 367 goto freepbuf;
root@mbed.org 0:5e1631496985 368 }
root@mbed.org 0:5e1631496985 369 #endif /* IP_REASS_CHECK_OVERLAP */
root@mbed.org 0:5e1631496985 370 iprh_prev->next_pbuf = new_p;
root@mbed.org 0:5e1631496985 371 } else {
root@mbed.org 0:5e1631496985 372 /* fragment with the lowest offset */
root@mbed.org 0:5e1631496985 373 ipr->p = new_p;
root@mbed.org 0:5e1631496985 374 }
root@mbed.org 0:5e1631496985 375 break;
root@mbed.org 0:5e1631496985 376 } else if(iprh->start == iprh_tmp->start) {
root@mbed.org 0:5e1631496985 377 /* received the same datagram twice: no need to keep the datagram */
root@mbed.org 0:5e1631496985 378 goto freepbuf;
root@mbed.org 0:5e1631496985 379 #if IP_REASS_CHECK_OVERLAP
root@mbed.org 0:5e1631496985 380 } else if(iprh->start < iprh_tmp->end) {
root@mbed.org 0:5e1631496985 381 /* overlap: no need to keep the new datagram */
root@mbed.org 0:5e1631496985 382 goto freepbuf;
root@mbed.org 0:5e1631496985 383 #endif /* IP_REASS_CHECK_OVERLAP */
root@mbed.org 0:5e1631496985 384 } else {
root@mbed.org 0:5e1631496985 385 /* Check if the fragments received so far have no wholes. */
root@mbed.org 0:5e1631496985 386 if (iprh_prev != NULL) {
root@mbed.org 0:5e1631496985 387 if (iprh_prev->end != iprh_tmp->start) {
root@mbed.org 0:5e1631496985 388 /* There is a fragment missing between the current
root@mbed.org 0:5e1631496985 389 * and the previous fragment */
root@mbed.org 0:5e1631496985 390 valid = 0;
root@mbed.org 0:5e1631496985 391 }
root@mbed.org 0:5e1631496985 392 }
root@mbed.org 0:5e1631496985 393 }
root@mbed.org 0:5e1631496985 394 q = iprh_tmp->next_pbuf;
root@mbed.org 0:5e1631496985 395 iprh_prev = iprh_tmp;
root@mbed.org 0:5e1631496985 396 }
root@mbed.org 0:5e1631496985 397
root@mbed.org 0:5e1631496985 398 /* If q is NULL, then we made it to the end of the list. Determine what to do now */
root@mbed.org 0:5e1631496985 399 if (q == NULL) {
root@mbed.org 0:5e1631496985 400 if (iprh_prev != NULL) {
root@mbed.org 0:5e1631496985 401 /* this is (for now), the fragment with the highest offset:
root@mbed.org 0:5e1631496985 402 * chain it to the last fragment */
root@mbed.org 0:5e1631496985 403 #if IP_REASS_CHECK_OVERLAP
root@mbed.org 0:5e1631496985 404 LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
root@mbed.org 0:5e1631496985 405 #endif /* IP_REASS_CHECK_OVERLAP */
root@mbed.org 0:5e1631496985 406 iprh_prev->next_pbuf = new_p;
root@mbed.org 0:5e1631496985 407 if (iprh_prev->end != iprh->start) {
root@mbed.org 0:5e1631496985 408 valid = 0;
root@mbed.org 0:5e1631496985 409 }
root@mbed.org 0:5e1631496985 410 } else {
root@mbed.org 0:5e1631496985 411 #if IP_REASS_CHECK_OVERLAP
root@mbed.org 0:5e1631496985 412 LWIP_ASSERT("no previous fragment, this must be the first fragment!",
root@mbed.org 0:5e1631496985 413 ipr->p == NULL);
root@mbed.org 0:5e1631496985 414 #endif /* IP_REASS_CHECK_OVERLAP */
root@mbed.org 0:5e1631496985 415 /* this is the first fragment we ever received for this ip datagram */
root@mbed.org 0:5e1631496985 416 ipr->p = new_p;
root@mbed.org 0:5e1631496985 417 }
root@mbed.org 0:5e1631496985 418 }
root@mbed.org 0:5e1631496985 419
root@mbed.org 0:5e1631496985 420 /* At this point, the validation part begins: */
root@mbed.org 0:5e1631496985 421 /* If we already received the last fragment */
root@mbed.org 0:5e1631496985 422 if ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0) {
root@mbed.org 0:5e1631496985 423 /* and had no wholes so far */
root@mbed.org 0:5e1631496985 424 if (valid) {
root@mbed.org 0:5e1631496985 425 /* then check if the rest of the fragments is here */
root@mbed.org 0:5e1631496985 426 /* Check if the queue starts with the first datagram */
root@mbed.org 0:5e1631496985 427 if (((struct ip_reass_helper*)ipr->p->payload)->start != 0) {
root@mbed.org 0:5e1631496985 428 valid = 0;
root@mbed.org 0:5e1631496985 429 } else {
root@mbed.org 0:5e1631496985 430 /* and check that there are no wholes after this datagram */
root@mbed.org 0:5e1631496985 431 iprh_prev = iprh;
root@mbed.org 0:5e1631496985 432 q = iprh->next_pbuf;
root@mbed.org 0:5e1631496985 433 while (q != NULL) {
root@mbed.org 0:5e1631496985 434 iprh = (struct ip_reass_helper*)q->payload;
root@mbed.org 0:5e1631496985 435 if (iprh_prev->end != iprh->start) {
root@mbed.org 0:5e1631496985 436 valid = 0;
root@mbed.org 0:5e1631496985 437 break;
root@mbed.org 0:5e1631496985 438 }
root@mbed.org 0:5e1631496985 439 iprh_prev = iprh;
root@mbed.org 0:5e1631496985 440 q = iprh->next_pbuf;
root@mbed.org 0:5e1631496985 441 }
root@mbed.org 0:5e1631496985 442 /* if still valid, all fragments are received
root@mbed.org 0:5e1631496985 443 * (because to the MF==0 already arrived */
root@mbed.org 0:5e1631496985 444 if (valid) {
root@mbed.org 0:5e1631496985 445 LWIP_ASSERT("sanity check", ipr->p != NULL);
root@mbed.org 0:5e1631496985 446 LWIP_ASSERT("sanity check",
root@mbed.org 0:5e1631496985 447 ((struct ip_reass_helper*)ipr->p->payload) != iprh);
root@mbed.org 0:5e1631496985 448 LWIP_ASSERT("validate_datagram:next_pbuf!=NULL",
root@mbed.org 0:5e1631496985 449 iprh->next_pbuf == NULL);
root@mbed.org 0:5e1631496985 450 LWIP_ASSERT("validate_datagram:datagram end!=datagram len",
root@mbed.org 0:5e1631496985 451 iprh->end == ipr->datagram_len);
root@mbed.org 0:5e1631496985 452 }
root@mbed.org 0:5e1631496985 453 }
root@mbed.org 0:5e1631496985 454 }
root@mbed.org 0:5e1631496985 455 /* If valid is 0 here, there are some fragments missing in the middle
root@mbed.org 0:5e1631496985 456 * (since MF == 0 has already arrived). Such datagrams simply time out if
root@mbed.org 0:5e1631496985 457 * no more fragments are received... */
root@mbed.org 0:5e1631496985 458 return valid;
root@mbed.org 0:5e1631496985 459 }
root@mbed.org 0:5e1631496985 460 /* If we come here, not all fragments were received, yet! */
root@mbed.org 0:5e1631496985 461 return 0; /* not yet valid! */
root@mbed.org 0:5e1631496985 462 #if IP_REASS_CHECK_OVERLAP
root@mbed.org 0:5e1631496985 463 freepbuf:
root@mbed.org 0:5e1631496985 464 ip_reass_pbufcount -= pbuf_clen(new_p);
root@mbed.org 0:5e1631496985 465 pbuf_free(new_p);
root@mbed.org 0:5e1631496985 466 return 0;
root@mbed.org 0:5e1631496985 467 #endif /* IP_REASS_CHECK_OVERLAP */
root@mbed.org 0:5e1631496985 468 }
root@mbed.org 0:5e1631496985 469
root@mbed.org 0:5e1631496985 470 /**
root@mbed.org 0:5e1631496985 471 * Reassembles incoming IP fragments into an IP datagram.
root@mbed.org 0:5e1631496985 472 *
root@mbed.org 0:5e1631496985 473 * @param p points to a pbuf chain of the fragment
root@mbed.org 0:5e1631496985 474 * @return NULL if reassembly is incomplete, ? otherwise
root@mbed.org 0:5e1631496985 475 */
root@mbed.org 0:5e1631496985 476 struct pbuf *
root@mbed.org 0:5e1631496985 477 ip_reass(struct pbuf *p)
root@mbed.org 0:5e1631496985 478 {
root@mbed.org 0:5e1631496985 479 struct pbuf *r;
root@mbed.org 0:5e1631496985 480 struct ip_hdr *fraghdr;
root@mbed.org 0:5e1631496985 481 struct ip_reassdata *ipr;
root@mbed.org 0:5e1631496985 482 struct ip_reass_helper *iprh;
root@mbed.org 0:5e1631496985 483 u16_t offset, len;
root@mbed.org 0:5e1631496985 484 u8_t clen;
root@mbed.org 0:5e1631496985 485 struct ip_reassdata *ipr_prev = NULL;
root@mbed.org 0:5e1631496985 486
root@mbed.org 0:5e1631496985 487 IPFRAG_STATS_INC(ip_frag.recv);
root@mbed.org 0:5e1631496985 488 snmp_inc_ipreasmreqds();
root@mbed.org 0:5e1631496985 489
root@mbed.org 0:5e1631496985 490 fraghdr = (struct ip_hdr*)p->payload;
root@mbed.org 0:5e1631496985 491
root@mbed.org 0:5e1631496985 492 if ((IPH_HL(fraghdr) * 4) != IP_HLEN) {
root@mbed.org 0:5e1631496985 493 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n"));
root@mbed.org 0:5e1631496985 494 IPFRAG_STATS_INC(ip_frag.err);
root@mbed.org 0:5e1631496985 495 goto nullreturn;
root@mbed.org 0:5e1631496985 496 }
root@mbed.org 0:5e1631496985 497
root@mbed.org 0:5e1631496985 498 offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
root@mbed.org 0:5e1631496985 499 len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
root@mbed.org 0:5e1631496985 500
root@mbed.org 0:5e1631496985 501 /* Check if we are allowed to enqueue more datagrams. */
root@mbed.org 0:5e1631496985 502 clen = pbuf_clen(p);
root@mbed.org 0:5e1631496985 503 if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
root@mbed.org 0:5e1631496985 504 #if IP_REASS_FREE_OLDEST
root@mbed.org 0:5e1631496985 505 if (!ip_reass_remove_oldest_datagram(fraghdr, clen) ||
root@mbed.org 0:5e1631496985 506 ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
root@mbed.org 0:5e1631496985 507 #endif /* IP_REASS_FREE_OLDEST */
root@mbed.org 0:5e1631496985 508 {
root@mbed.org 0:5e1631496985 509 /* No datagram could be freed and still too many pbufs enqueued */
root@mbed.org 0:5e1631496985 510 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
root@mbed.org 0:5e1631496985 511 ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
root@mbed.org 0:5e1631496985 512 IPFRAG_STATS_INC(ip_frag.memerr);
root@mbed.org 0:5e1631496985 513 /* @todo: send ICMP time exceeded here? */
root@mbed.org 0:5e1631496985 514 /* drop this pbuf */
root@mbed.org 0:5e1631496985 515 goto nullreturn;
root@mbed.org 0:5e1631496985 516 }
root@mbed.org 0:5e1631496985 517 }
root@mbed.org 0:5e1631496985 518
root@mbed.org 0:5e1631496985 519 /* Look for the datagram the fragment belongs to in the current datagram queue,
root@mbed.org 0:5e1631496985 520 * remembering the previous in the queue for later dequeueing. */
root@mbed.org 0:5e1631496985 521 for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
root@mbed.org 0:5e1631496985 522 /* Check if the incoming fragment matches the one currently present
root@mbed.org 0:5e1631496985 523 in the reassembly buffer. If so, we proceed with copying the
root@mbed.org 0:5e1631496985 524 fragment into the buffer. */
root@mbed.org 0:5e1631496985 525 if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
root@mbed.org 0:5e1631496985 526 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
root@mbed.org 0:5e1631496985 527 ntohs(IPH_ID(fraghdr))));
root@mbed.org 0:5e1631496985 528 IPFRAG_STATS_INC(ip_frag.cachehit);
root@mbed.org 0:5e1631496985 529 break;
root@mbed.org 0:5e1631496985 530 }
root@mbed.org 0:5e1631496985 531 ipr_prev = ipr;
root@mbed.org 0:5e1631496985 532 }
root@mbed.org 0:5e1631496985 533
root@mbed.org 0:5e1631496985 534 if (ipr == NULL) {
root@mbed.org 0:5e1631496985 535 /* Enqueue a new datagram into the datagram queue */
root@mbed.org 0:5e1631496985 536 ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
root@mbed.org 0:5e1631496985 537 /* Bail if unable to enqueue */
root@mbed.org 0:5e1631496985 538 if(ipr == NULL) {
root@mbed.org 0:5e1631496985 539 goto nullreturn;
root@mbed.org 0:5e1631496985 540 }
root@mbed.org 0:5e1631496985 541 } else {
root@mbed.org 0:5e1631496985 542 if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) &&
root@mbed.org 0:5e1631496985 543 ((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
root@mbed.org 0:5e1631496985 544 /* ipr->iphdr is not the header from the first fragment, but fraghdr is
root@mbed.org 0:5e1631496985 545 * -> copy fraghdr into ipr->iphdr since we want to have the header
root@mbed.org 0:5e1631496985 546 * of the first fragment (for ICMP time exceeded and later, for copying
root@mbed.org 0:5e1631496985 547 * all options, if supported)*/
root@mbed.org 0:5e1631496985 548 SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
root@mbed.org 0:5e1631496985 549 }
root@mbed.org 0:5e1631496985 550 }
root@mbed.org 0:5e1631496985 551 /* Track the current number of pbufs current 'in-flight', in order to limit
root@mbed.org 0:5e1631496985 552 the number of fragments that may be enqueued at any one time */
root@mbed.org 0:5e1631496985 553 ip_reass_pbufcount += clen;
root@mbed.org 0:5e1631496985 554
root@mbed.org 0:5e1631496985 555 /* At this point, we have either created a new entry or pointing
root@mbed.org 0:5e1631496985 556 * to an existing one */
root@mbed.org 0:5e1631496985 557
root@mbed.org 0:5e1631496985 558 /* check for 'no more fragments', and update queue entry*/
root@mbed.org 0:5e1631496985 559 if ((ntohs(IPH_OFFSET(fraghdr)) & IP_MF) == 0) {
root@mbed.org 0:5e1631496985 560 ipr->flags |= IP_REASS_FLAG_LASTFRAG;
root@mbed.org 0:5e1631496985 561 ipr->datagram_len = offset + len;
root@mbed.org 0:5e1631496985 562 LWIP_DEBUGF(IP_REASS_DEBUG,
root@mbed.org 0:5e1631496985 563 ("ip_reass: last fragment seen, total len %"S16_F"\n",
root@mbed.org 0:5e1631496985 564 ipr->datagram_len));
root@mbed.org 0:5e1631496985 565 }
root@mbed.org 0:5e1631496985 566 /* find the right place to insert this pbuf */
root@mbed.org 0:5e1631496985 567 /* @todo: trim pbufs if fragments are overlapping */
root@mbed.org 0:5e1631496985 568 if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) {
root@mbed.org 0:5e1631496985 569 /* the totally last fragment (flag more fragments = 0) was received at least
root@mbed.org 0:5e1631496985 570 * once AND all fragments are received */
root@mbed.org 0:5e1631496985 571 ipr->datagram_len += IP_HLEN;
root@mbed.org 0:5e1631496985 572
root@mbed.org 0:5e1631496985 573 /* save the second pbuf before copying the header over the pointer */
root@mbed.org 0:5e1631496985 574 r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf;
root@mbed.org 0:5e1631496985 575
root@mbed.org 0:5e1631496985 576 /* copy the original ip header back to the first pbuf */
root@mbed.org 0:5e1631496985 577 fraghdr = (struct ip_hdr*)(ipr->p->payload);
root@mbed.org 0:5e1631496985 578 SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
root@mbed.org 0:5e1631496985 579 IPH_LEN_SET(fraghdr, htons(ipr->datagram_len));
root@mbed.org 0:5e1631496985 580 IPH_OFFSET_SET(fraghdr, 0);
root@mbed.org 0:5e1631496985 581 IPH_CHKSUM_SET(fraghdr, 0);
root@mbed.org 0:5e1631496985 582 /* @todo: do we need to set calculate the correct checksum? */
root@mbed.org 0:5e1631496985 583 IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));
root@mbed.org 0:5e1631496985 584
root@mbed.org 0:5e1631496985 585 p = ipr->p;
root@mbed.org 0:5e1631496985 586
root@mbed.org 0:5e1631496985 587 /* chain together the pbufs contained within the reass_data list. */
root@mbed.org 0:5e1631496985 588 while(r != NULL) {
root@mbed.org 0:5e1631496985 589 iprh = (struct ip_reass_helper*)r->payload;
root@mbed.org 0:5e1631496985 590
root@mbed.org 0:5e1631496985 591 /* hide the ip header for every succeding fragment */
root@mbed.org 0:5e1631496985 592 pbuf_header(r, -IP_HLEN);
root@mbed.org 0:5e1631496985 593 pbuf_cat(p, r);
root@mbed.org 0:5e1631496985 594 r = iprh->next_pbuf;
root@mbed.org 0:5e1631496985 595 }
root@mbed.org 0:5e1631496985 596 /* release the sources allocate for the fragment queue entry */
root@mbed.org 0:5e1631496985 597 ip_reass_dequeue_datagram(ipr, ipr_prev);
root@mbed.org 0:5e1631496985 598
root@mbed.org 0:5e1631496985 599 /* and adjust the number of pbufs currently queued for reassembly. */
root@mbed.org 0:5e1631496985 600 ip_reass_pbufcount -= pbuf_clen(p);
root@mbed.org 0:5e1631496985 601
root@mbed.org 0:5e1631496985 602 /* Return the pbuf chain */
root@mbed.org 0:5e1631496985 603 return p;
root@mbed.org 0:5e1631496985 604 }
root@mbed.org 0:5e1631496985 605 /* the datagram is not (yet?) reassembled completely */
root@mbed.org 0:5e1631496985 606 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
root@mbed.org 0:5e1631496985 607 return NULL;
root@mbed.org 0:5e1631496985 608
root@mbed.org 0:5e1631496985 609 nullreturn:
root@mbed.org 0:5e1631496985 610 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n"));
root@mbed.org 0:5e1631496985 611 IPFRAG_STATS_INC(ip_frag.drop);
root@mbed.org 0:5e1631496985 612 pbuf_free(p);
root@mbed.org 0:5e1631496985 613 return NULL;
root@mbed.org 0:5e1631496985 614 }
root@mbed.org 0:5e1631496985 615 #endif /* IP_REASSEMBLY */
root@mbed.org 0:5e1631496985 616
root@mbed.org 0:5e1631496985 617 #if IP_FRAG
root@mbed.org 0:5e1631496985 618 #if IP_FRAG_USES_STATIC_BUF
root@mbed.org 0:5e1631496985 619 static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU + MEM_ALIGNMENT - 1)];
root@mbed.org 0:5e1631496985 620 #endif /* IP_FRAG_USES_STATIC_BUF */
root@mbed.org 0:5e1631496985 621
root@mbed.org 0:5e1631496985 622 /**
root@mbed.org 0:5e1631496985 623 * Fragment an IP datagram if too large for the netif.
root@mbed.org 0:5e1631496985 624 *
root@mbed.org 0:5e1631496985 625 * Chop the datagram in MTU sized chunks and send them in order
root@mbed.org 0:5e1631496985 626 * by using a fixed size static memory buffer (PBUF_REF) or
root@mbed.org 0:5e1631496985 627 * point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF).
root@mbed.org 0:5e1631496985 628 *
root@mbed.org 0:5e1631496985 629 * @param p ip packet to send
root@mbed.org 0:5e1631496985 630 * @param netif the netif on which to send
root@mbed.org 0:5e1631496985 631 * @param dest destination ip address to which to send
root@mbed.org 0:5e1631496985 632 *
root@mbed.org 0:5e1631496985 633 * @return ERR_OK if sent successfully, err_t otherwise
root@mbed.org 0:5e1631496985 634 */
root@mbed.org 0:5e1631496985 635 err_t
root@mbed.org 0:5e1631496985 636 ip_frag(struct pbuf *p, struct netif *netif, struct ip_addr *dest)
root@mbed.org 0:5e1631496985 637 {
root@mbed.org 0:5e1631496985 638 struct pbuf *rambuf;
root@mbed.org 0:5e1631496985 639 #if IP_FRAG_USES_STATIC_BUF
root@mbed.org 0:5e1631496985 640 struct pbuf *header;
root@mbed.org 0:5e1631496985 641 #else
root@mbed.org 0:5e1631496985 642 struct pbuf *newpbuf;
root@mbed.org 0:5e1631496985 643 struct ip_hdr *original_iphdr;
root@mbed.org 0:5e1631496985 644 #endif
root@mbed.org 0:5e1631496985 645 struct ip_hdr *iphdr;
root@mbed.org 0:5e1631496985 646 u16_t nfb;
root@mbed.org 0:5e1631496985 647 u16_t left, cop;
root@mbed.org 0:5e1631496985 648 u16_t mtu = netif->mtu;
root@mbed.org 0:5e1631496985 649 u16_t ofo, omf;
root@mbed.org 0:5e1631496985 650 u16_t last;
root@mbed.org 0:5e1631496985 651 u16_t poff = IP_HLEN;
root@mbed.org 0:5e1631496985 652 u16_t tmp;
root@mbed.org 0:5e1631496985 653 #if !IP_FRAG_USES_STATIC_BUF
root@mbed.org 0:5e1631496985 654 u16_t newpbuflen = 0;
root@mbed.org 0:5e1631496985 655 u16_t left_to_copy;
root@mbed.org 0:5e1631496985 656 #endif
root@mbed.org 0:5e1631496985 657
root@mbed.org 0:5e1631496985 658 /* Get a RAM based MTU sized pbuf */
root@mbed.org 0:5e1631496985 659 #if IP_FRAG_USES_STATIC_BUF
root@mbed.org 0:5e1631496985 660 /* When using a static buffer, we use a PBUF_REF, which we will
root@mbed.org 0:5e1631496985 661 * use to reference the packet (without link header).
root@mbed.org 0:5e1631496985 662 * Layer and length is irrelevant.
root@mbed.org 0:5e1631496985 663 */
root@mbed.org 0:5e1631496985 664 rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
root@mbed.org 0:5e1631496985 665 if (rambuf == NULL) {
root@mbed.org 0:5e1631496985 666 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n"));
root@mbed.org 0:5e1631496985 667 return ERR_MEM;
root@mbed.org 0:5e1631496985 668 }
root@mbed.org 0:5e1631496985 669 rambuf->tot_len = rambuf->len = mtu;
root@mbed.org 0:5e1631496985 670 rambuf->payload = LWIP_MEM_ALIGN((void *)buf);
root@mbed.org 0:5e1631496985 671
root@mbed.org 0:5e1631496985 672 /* Copy the IP header in it */
root@mbed.org 0:5e1631496985 673 iphdr = rambuf->payload;
root@mbed.org 0:5e1631496985 674 SMEMCPY(iphdr, p->payload, IP_HLEN);
root@mbed.org 0:5e1631496985 675 #else /* IP_FRAG_USES_STATIC_BUF */
root@mbed.org 0:5e1631496985 676 original_iphdr = (struct ip_hdr *)p->payload;
root@mbed.org 0:5e1631496985 677 iphdr = original_iphdr;
root@mbed.org 0:5e1631496985 678 #endif /* IP_FRAG_USES_STATIC_BUF */
root@mbed.org 0:5e1631496985 679
root@mbed.org 0:5e1631496985 680 /* Save original offset */
root@mbed.org 0:5e1631496985 681 tmp = ntohs(IPH_OFFSET(iphdr));
root@mbed.org 0:5e1631496985 682 ofo = tmp & IP_OFFMASK;
root@mbed.org 0:5e1631496985 683 omf = tmp & IP_MF;
root@mbed.org 0:5e1631496985 684
root@mbed.org 0:5e1631496985 685 left = p->tot_len - IP_HLEN;
root@mbed.org 0:5e1631496985 686
root@mbed.org 0:5e1631496985 687 nfb = (mtu - IP_HLEN) / 8;
root@mbed.org 0:5e1631496985 688
root@mbed.org 0:5e1631496985 689 while (left) {
root@mbed.org 0:5e1631496985 690 last = (left <= mtu - IP_HLEN);
root@mbed.org 0:5e1631496985 691
root@mbed.org 0:5e1631496985 692 /* Set new offset and MF flag */
root@mbed.org 0:5e1631496985 693 tmp = omf | (IP_OFFMASK & (ofo));
root@mbed.org 0:5e1631496985 694 if (!last)
root@mbed.org 0:5e1631496985 695 tmp = tmp | IP_MF;
root@mbed.org 0:5e1631496985 696
root@mbed.org 0:5e1631496985 697 /* Fill this fragment */
root@mbed.org 0:5e1631496985 698 cop = last ? left : nfb * 8;
root@mbed.org 0:5e1631496985 699
root@mbed.org 0:5e1631496985 700 #if IP_FRAG_USES_STATIC_BUF
root@mbed.org 0:5e1631496985 701 poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
root@mbed.org 0:5e1631496985 702 #else /* IP_FRAG_USES_STATIC_BUF */
root@mbed.org 0:5e1631496985 703 /* When not using a static buffer, create a chain of pbufs.
root@mbed.org 0:5e1631496985 704 * The first will be a PBUF_RAM holding the link and IP header.
root@mbed.org 0:5e1631496985 705 * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
root@mbed.org 0:5e1631496985 706 * but limited to the size of an mtu.
root@mbed.org 0:5e1631496985 707 */
root@mbed.org 0:5e1631496985 708 rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
root@mbed.org 0:5e1631496985 709 if (rambuf == NULL) {
root@mbed.org 0:5e1631496985 710 return ERR_MEM;
root@mbed.org 0:5e1631496985 711 }
root@mbed.org 0:5e1631496985 712 LWIP_ASSERT("this needs a pbuf in one piece!",
root@mbed.org 0:5e1631496985 713 (p->len >= (IP_HLEN)));
root@mbed.org 0:5e1631496985 714 SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
root@mbed.org 0:5e1631496985 715 iphdr = (struct ip_hdr *)rambuf->payload;
root@mbed.org 0:5e1631496985 716
root@mbed.org 0:5e1631496985 717 /* Can just adjust p directly for needed offset. */
root@mbed.org 0:5e1631496985 718 p->payload = (u8_t *)p->payload + poff;
root@mbed.org 0:5e1631496985 719 p->len -= poff;
root@mbed.org 0:5e1631496985 720
root@mbed.org 0:5e1631496985 721 left_to_copy = cop;
root@mbed.org 0:5e1631496985 722 while (left_to_copy) {
root@mbed.org 0:5e1631496985 723 newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
root@mbed.org 0:5e1631496985 724 /* Is this pbuf already empty? */
root@mbed.org 0:5e1631496985 725 if (!newpbuflen) {
root@mbed.org 0:5e1631496985 726 p = p->next;
root@mbed.org 0:5e1631496985 727 continue;
root@mbed.org 0:5e1631496985 728 }
root@mbed.org 0:5e1631496985 729 newpbuf = pbuf_alloc(PBUF_RAW, 0, PBUF_REF);
root@mbed.org 0:5e1631496985 730 if (newpbuf == NULL) {
root@mbed.org 0:5e1631496985 731 pbuf_free(rambuf);
root@mbed.org 0:5e1631496985 732 return ERR_MEM;
root@mbed.org 0:5e1631496985 733 }
root@mbed.org 0:5e1631496985 734 /* Mirror this pbuf, although we might not need all of it. */
root@mbed.org 0:5e1631496985 735 newpbuf->payload = p->payload;
root@mbed.org 0:5e1631496985 736 newpbuf->len = newpbuf->tot_len = newpbuflen;
root@mbed.org 0:5e1631496985 737 /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
root@mbed.org 0:5e1631496985 738 * so that it is removed when pbuf_dechain is later called on rambuf.
root@mbed.org 0:5e1631496985 739 */
root@mbed.org 0:5e1631496985 740 pbuf_cat(rambuf, newpbuf);
root@mbed.org 0:5e1631496985 741 left_to_copy -= newpbuflen;
root@mbed.org 0:5e1631496985 742 if (left_to_copy)
root@mbed.org 0:5e1631496985 743 p = p->next;
root@mbed.org 0:5e1631496985 744 }
root@mbed.org 0:5e1631496985 745 poff = newpbuflen;
root@mbed.org 0:5e1631496985 746 #endif /* IP_FRAG_USES_STATIC_BUF */
root@mbed.org 0:5e1631496985 747
root@mbed.org 0:5e1631496985 748 /* Correct header */
root@mbed.org 0:5e1631496985 749 IPH_OFFSET_SET(iphdr, htons(tmp));
root@mbed.org 0:5e1631496985 750 IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
root@mbed.org 0:5e1631496985 751 IPH_CHKSUM_SET(iphdr, 0);
root@mbed.org 0:5e1631496985 752 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
root@mbed.org 0:5e1631496985 753
root@mbed.org 0:5e1631496985 754 #if IP_FRAG_USES_STATIC_BUF
root@mbed.org 0:5e1631496985 755 if (last)
root@mbed.org 0:5e1631496985 756 pbuf_realloc(rambuf, left + IP_HLEN);
root@mbed.org 0:5e1631496985 757
root@mbed.org 0:5e1631496985 758 /* This part is ugly: we alloc a RAM based pbuf for
root@mbed.org 0:5e1631496985 759 * the link level header for each chunk and then
root@mbed.org 0:5e1631496985 760 * free it.A PBUF_ROM style pbuf for which pbuf_header
root@mbed.org 0:5e1631496985 761 * worked would make things simpler.
root@mbed.org 0:5e1631496985 762 */
root@mbed.org 0:5e1631496985 763 header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
root@mbed.org 0:5e1631496985 764 if (header != NULL) {
root@mbed.org 0:5e1631496985 765 pbuf_chain(header, rambuf);
root@mbed.org 0:5e1631496985 766 netif->output(netif, header, dest);
root@mbed.org 0:5e1631496985 767 IPFRAG_STATS_INC(ip_frag.xmit);
root@mbed.org 0:5e1631496985 768 snmp_inc_ipfragcreates();
root@mbed.org 0:5e1631496985 769 pbuf_free(header);
root@mbed.org 0:5e1631496985 770 } else {
root@mbed.org 0:5e1631496985 771 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
root@mbed.org 0:5e1631496985 772 pbuf_free(rambuf);
root@mbed.org 0:5e1631496985 773 return ERR_MEM;
root@mbed.org 0:5e1631496985 774 }
root@mbed.org 0:5e1631496985 775 #else /* IP_FRAG_USES_STATIC_BUF */
root@mbed.org 0:5e1631496985 776 /* No need for separate header pbuf - we allowed room for it in rambuf
root@mbed.org 0:5e1631496985 777 * when allocated.
root@mbed.org 0:5e1631496985 778 */
root@mbed.org 0:5e1631496985 779 netif->output(netif, rambuf, dest);
root@mbed.org 0:5e1631496985 780 IPFRAG_STATS_INC(ip_frag.xmit);
root@mbed.org 0:5e1631496985 781
root@mbed.org 0:5e1631496985 782 /* Unfortunately we can't reuse rambuf - the hardware may still be
root@mbed.org 0:5e1631496985 783 * using the buffer. Instead we free it (and the ensuing chain) and
root@mbed.org 0:5e1631496985 784 * recreate it next time round the loop. If we're lucky the hardware
root@mbed.org 0:5e1631496985 785 * will have already sent the packet, the free will really free, and
root@mbed.org 0:5e1631496985 786 * there will be zero memory penalty.
root@mbed.org 0:5e1631496985 787 */
root@mbed.org 0:5e1631496985 788
root@mbed.org 0:5e1631496985 789 pbuf_free(rambuf);
root@mbed.org 0:5e1631496985 790 #endif /* IP_FRAG_USES_STATIC_BUF */
root@mbed.org 0:5e1631496985 791 left -= cop;
root@mbed.org 0:5e1631496985 792 ofo += nfb;
root@mbed.org 0:5e1631496985 793 }
root@mbed.org 0:5e1631496985 794 #if IP_FRAG_USES_STATIC_BUF
root@mbed.org 0:5e1631496985 795 pbuf_free(rambuf);
root@mbed.org 0:5e1631496985 796 #endif /* IP_FRAG_USES_STATIC_BUF */
root@mbed.org 0:5e1631496985 797 snmp_inc_ipfragoks();
root@mbed.org 0:5e1631496985 798 return ERR_OK;
root@mbed.org 0:5e1631496985 799 }
root@mbed.org 0:5e1631496985 800 #endif /* IP_FRAG */