Mihail Stoyanov / HTTPServer

My fork of the HTTPServer (working)

Dependents:   DGWWebServer LAN2

Core/lwIP/core/ipv4/ip_frag.c@0:7a64fbb4069d, 2012-08-06 (annotated)

Committer:
screamer
Date:
Mon Aug 06 09:23:14 2012 +0000
Revision:
0:7a64fbb4069d
[mbed] converted /DGWWebServer/HTTPServer

Who changed what in which revision?

UserRevisionLine numberNew contents of line
screamer 0:7a64fbb4069d 1 /**
screamer 0:7a64fbb4069d 2 * @file
screamer 0:7a64fbb4069d 3 * This is the IPv4 packet segmentation and reassembly implementation.
screamer 0:7a64fbb4069d 4 *
screamer 0:7a64fbb4069d 5 */
screamer 0:7a64fbb4069d 6
screamer 0:7a64fbb4069d 7 /*
screamer 0:7a64fbb4069d 8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
screamer 0:7a64fbb4069d 9 * All rights reserved.
screamer 0:7a64fbb4069d 10 *
screamer 0:7a64fbb4069d 11 * Redistribution and use in source and binary forms, with or without modification,
screamer 0:7a64fbb4069d 12 * are permitted provided that the following conditions are met:
screamer 0:7a64fbb4069d 13 *
screamer 0:7a64fbb4069d 14 * 1. Redistributions of source code must retain the above copyright notice,
screamer 0:7a64fbb4069d 15 * this list of conditions and the following disclaimer.
screamer 0:7a64fbb4069d 16 * 2. Redistributions in binary form must reproduce the above copyright notice,
screamer 0:7a64fbb4069d 17 * this list of conditions and the following disclaimer in the documentation
screamer 0:7a64fbb4069d 18 * and/or other materials provided with the distribution.
screamer 0:7a64fbb4069d 19 * 3. The name of the author may not be used to endorse or promote products
screamer 0:7a64fbb4069d 20 * derived from this software without specific prior written permission.
screamer 0:7a64fbb4069d 21 *
screamer 0:7a64fbb4069d 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
screamer 0:7a64fbb4069d 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
screamer 0:7a64fbb4069d 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
screamer 0:7a64fbb4069d 25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
screamer 0:7a64fbb4069d 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
screamer 0:7a64fbb4069d 27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
screamer 0:7a64fbb4069d 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
screamer 0:7a64fbb4069d 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
screamer 0:7a64fbb4069d 30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
screamer 0:7a64fbb4069d 31 * OF SUCH DAMAGE.
screamer 0:7a64fbb4069d 32 *
screamer 0:7a64fbb4069d 33 * This file is part of the lwIP TCP/IP stack.
screamer 0:7a64fbb4069d 34 *
screamer 0:7a64fbb4069d 35 * Author: Jani Monoses <jani@iv.ro>
screamer 0:7a64fbb4069d 36 * Simon Goldschmidt
screamer 0:7a64fbb4069d 37 * original reassembly code by Adam Dunkels <adam@sics.se>
screamer 0:7a64fbb4069d 38 *
screamer 0:7a64fbb4069d 39 */
screamer 0:7a64fbb4069d 40
screamer 0:7a64fbb4069d 41 #include "lwip/opt.h"
screamer 0:7a64fbb4069d 42 #include "lwip/ip_frag.h"
screamer 0:7a64fbb4069d 43 #include "lwip/ip.h"
screamer 0:7a64fbb4069d 44 #include "lwip/inet.h"
screamer 0:7a64fbb4069d 45 #include "lwip/inet_chksum.h"
screamer 0:7a64fbb4069d 46 #include "lwip/netif.h"
screamer 0:7a64fbb4069d 47 #include "lwip/snmp.h"
screamer 0:7a64fbb4069d 48 #include "lwip/stats.h"
screamer 0:7a64fbb4069d 49 #include "lwip/icmp.h"
screamer 0:7a64fbb4069d 50
screamer 0:7a64fbb4069d 51 #include <string.h>
screamer 0:7a64fbb4069d 52
screamer 0:7a64fbb4069d 53 #if IP_REASSEMBLY
screamer 0:7a64fbb4069d 54 /**
screamer 0:7a64fbb4069d 55 * The IP reassembly code currently has the following limitations:
screamer 0:7a64fbb4069d 56 * - IP header options are not supported
screamer 0:7a64fbb4069d 57 * - fragments must not overlap (e.g. due to different routes),
screamer 0:7a64fbb4069d 58 * currently, overlapping or duplicate fragments are thrown away
screamer 0:7a64fbb4069d 59 * if IP_REASS_CHECK_OVERLAP=1 (the default)!
screamer 0:7a64fbb4069d 60 *
screamer 0:7a64fbb4069d 61 * @todo: work with IP header options
screamer 0:7a64fbb4069d 62 */
screamer 0:7a64fbb4069d 63
screamer 0:7a64fbb4069d 64 /** Setting this to 0, you can turn off checking the fragments for overlapping
screamer 0:7a64fbb4069d 65 * regions. The code gets a little smaller. Only use this if you know that
screamer 0:7a64fbb4069d 66 * overlapping won't occur on your network! */
screamer 0:7a64fbb4069d 67 #ifndef IP_REASS_CHECK_OVERLAP
screamer 0:7a64fbb4069d 68 #define IP_REASS_CHECK_OVERLAP 1
screamer 0:7a64fbb4069d 69 #endif /* IP_REASS_CHECK_OVERLAP */
screamer 0:7a64fbb4069d 70
screamer 0:7a64fbb4069d 71 /** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
screamer 0:7a64fbb4069d 72 * full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
screamer 0:7a64fbb4069d 73 * Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
screamer 0:7a64fbb4069d 74 * is set to 1, so one datagram can be reassembled at a time, only. */
screamer 0:7a64fbb4069d 75 #ifndef IP_REASS_FREE_OLDEST
screamer 0:7a64fbb4069d 76 #define IP_REASS_FREE_OLDEST 1
screamer 0:7a64fbb4069d 77 #endif /* IP_REASS_FREE_OLDEST */
screamer 0:7a64fbb4069d 78
screamer 0:7a64fbb4069d 79 #define IP_REASS_FLAG_LASTFRAG 0x01
screamer 0:7a64fbb4069d 80
screamer 0:7a64fbb4069d 81 /** This is a helper struct which holds the starting
screamer 0:7a64fbb4069d 82 * offset and the ending offset of this fragment to
screamer 0:7a64fbb4069d 83 * easily chain the fragments.
screamer 0:7a64fbb4069d 84 * It has to be packed since it has to fit inside the IP header.
screamer 0:7a64fbb4069d 85 */
screamer 0:7a64fbb4069d 86
screamer 0:7a64fbb4069d 87 // XXX: For armcc
screamer 0:7a64fbb4069d 88 struct ip_reass_helper {
screamer 0:7a64fbb4069d 89 struct pbuf *next_pbuf;
screamer 0:7a64fbb4069d 90 u16_t start;
screamer 0:7a64fbb4069d 91 u16_t end;
screamer 0:7a64fbb4069d 92 };
screamer 0:7a64fbb4069d 93
screamer 0:7a64fbb4069d 94 /* // Will not work with armcc
screamer 0:7a64fbb4069d 95 #ifdef PACK_STRUCT_USE_INCLUDES
screamer 0:7a64fbb4069d 96 # include "arch/bpstruct.h"
screamer 0:7a64fbb4069d 97 #endif
screamer 0:7a64fbb4069d 98 PACK_STRUCT_BEGIN
screamer 0:7a64fbb4069d 99 struct ip_reass_helper {
screamer 0:7a64fbb4069d 100 PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
screamer 0:7a64fbb4069d 101 PACK_STRUCT_FIELD(u16_t start);
screamer 0:7a64fbb4069d 102 PACK_STRUCT_FIELD(u16_t end);
screamer 0:7a64fbb4069d 103 } PACK_STRUCT_STRUCT;
screamer 0:7a64fbb4069d 104 PACK_STRUCT_END
screamer 0:7a64fbb4069d 105 #ifdef PACK_STRUCT_USE_INCLUDES
screamer 0:7a64fbb4069d 106 # include "arch/epstruct.h"
screamer 0:7a64fbb4069d 107 #endif
screamer 0:7a64fbb4069d 108 */
screamer 0:7a64fbb4069d 109
screamer 0:7a64fbb4069d 110 #define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB) \
screamer 0:7a64fbb4069d 111 (ip_addr_cmp(&(iphdrA)->src, &(iphdrB)->src) && \
screamer 0:7a64fbb4069d 112 ip_addr_cmp(&(iphdrA)->dest, &(iphdrB)->dest) && \
screamer 0:7a64fbb4069d 113 IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0
screamer 0:7a64fbb4069d 114
screamer 0:7a64fbb4069d 115 /* global variables */
screamer 0:7a64fbb4069d 116 static struct ip_reassdata *reassdatagrams;
screamer 0:7a64fbb4069d 117 static u16_t ip_reass_pbufcount;
screamer 0:7a64fbb4069d 118
screamer 0:7a64fbb4069d 119 /* function prototypes */
screamer 0:7a64fbb4069d 120 static void ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
screamer 0:7a64fbb4069d 121 static int ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
screamer 0:7a64fbb4069d 122
screamer 0:7a64fbb4069d 123 /**
screamer 0:7a64fbb4069d 124 * Reassembly timer base function
screamer 0:7a64fbb4069d 125 * for both NO_SYS == 0 and 1 (!).
screamer 0:7a64fbb4069d 126 *
screamer 0:7a64fbb4069d 127 * Should be called every 1000 msec (defined by IP_TMR_INTERVAL).
screamer 0:7a64fbb4069d 128 */
screamer 0:7a64fbb4069d 129 void
screamer 0:7a64fbb4069d 130 ip_reass_tmr(void)
screamer 0:7a64fbb4069d 131 {
screamer 0:7a64fbb4069d 132 struct ip_reassdata *r, *prev = NULL;
screamer 0:7a64fbb4069d 133
screamer 0:7a64fbb4069d 134 r = reassdatagrams;
screamer 0:7a64fbb4069d 135 while (r != NULL) {
screamer 0:7a64fbb4069d 136 /* Decrement the timer. Once it reaches 0,
screamer 0:7a64fbb4069d 137 * clean up the incomplete fragment assembly */
screamer 0:7a64fbb4069d 138 if (r->timer > 0) {
screamer 0:7a64fbb4069d 139 r->timer--;
screamer 0:7a64fbb4069d 140 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)r->timer));
screamer 0:7a64fbb4069d 141 prev = r;
screamer 0:7a64fbb4069d 142 r = r->next;
screamer 0:7a64fbb4069d 143 } else {
screamer 0:7a64fbb4069d 144 /* reassembly timed out */
screamer 0:7a64fbb4069d 145 struct ip_reassdata *tmp;
screamer 0:7a64fbb4069d 146 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out\n"));
screamer 0:7a64fbb4069d 147 tmp = r;
screamer 0:7a64fbb4069d 148 /* get the next pointer before freeing */
screamer 0:7a64fbb4069d 149 r = r->next;
screamer 0:7a64fbb4069d 150 /* free the helper struct and all enqueued pbufs */
screamer 0:7a64fbb4069d 151 ip_reass_free_complete_datagram(tmp, prev);
screamer 0:7a64fbb4069d 152 }
screamer 0:7a64fbb4069d 153 }
screamer 0:7a64fbb4069d 154 }
screamer 0:7a64fbb4069d 155
screamer 0:7a64fbb4069d 156 /**
screamer 0:7a64fbb4069d 157 * Free a datagram (struct ip_reassdata) and all its pbufs.
screamer 0:7a64fbb4069d 158 * Updates the total count of enqueued pbufs (ip_reass_pbufcount),
screamer 0:7a64fbb4069d 159 * SNMP counters and sends an ICMP time exceeded packet.
screamer 0:7a64fbb4069d 160 *
screamer 0:7a64fbb4069d 161 * @param ipr datagram to free
screamer 0:7a64fbb4069d 162 * @param prev the previous datagram in the linked list
screamer 0:7a64fbb4069d 163 * @return the number of pbufs freed
screamer 0:7a64fbb4069d 164 */
screamer 0:7a64fbb4069d 165 static int
screamer 0:7a64fbb4069d 166 ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
screamer 0:7a64fbb4069d 167 {
screamer 0:7a64fbb4069d 168 int pbufs_freed = 0;
screamer 0:7a64fbb4069d 169 struct pbuf *p;
screamer 0:7a64fbb4069d 170 struct ip_reass_helper *iprh;
screamer 0:7a64fbb4069d 171
screamer 0:7a64fbb4069d 172 LWIP_ASSERT("prev != ipr", prev != ipr);
screamer 0:7a64fbb4069d 173 if (prev != NULL) {
screamer 0:7a64fbb4069d 174 LWIP_ASSERT("prev->next == ipr", prev->next == ipr);
screamer 0:7a64fbb4069d 175 }
screamer 0:7a64fbb4069d 176
screamer 0:7a64fbb4069d 177 snmp_inc_ipreasmfails();
screamer 0:7a64fbb4069d 178 #if LWIP_ICMP
screamer 0:7a64fbb4069d 179 iprh = (struct ip_reass_helper *)ipr->p->payload;
screamer 0:7a64fbb4069d 180 if (iprh->start == 0) {
screamer 0:7a64fbb4069d 181 /* The first fragment was received, send ICMP time exceeded. */
screamer 0:7a64fbb4069d 182 /* First, de-queue the first pbuf from r->p. */
screamer 0:7a64fbb4069d 183 p = ipr->p;
screamer 0:7a64fbb4069d 184 ipr->p = iprh->next_pbuf;
screamer 0:7a64fbb4069d 185 /* Then, copy the original header into it. */
screamer 0:7a64fbb4069d 186 SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN);
screamer 0:7a64fbb4069d 187 icmp_time_exceeded(p, ICMP_TE_FRAG);
screamer 0:7a64fbb4069d 188 pbufs_freed += pbuf_clen(p);
screamer 0:7a64fbb4069d 189 pbuf_free(p);
screamer 0:7a64fbb4069d 190 }
screamer 0:7a64fbb4069d 191 #endif /* LWIP_ICMP */
screamer 0:7a64fbb4069d 192
screamer 0:7a64fbb4069d 193 /* First, free all received pbufs. The individual pbufs need to be released
screamer 0:7a64fbb4069d 194 separately as they have not yet been chained */
screamer 0:7a64fbb4069d 195 p = ipr->p;
screamer 0:7a64fbb4069d 196 while (p != NULL) {
screamer 0:7a64fbb4069d 197 struct pbuf *pcur;
screamer 0:7a64fbb4069d 198 iprh = (struct ip_reass_helper *)p->payload;
screamer 0:7a64fbb4069d 199 pcur = p;
screamer 0:7a64fbb4069d 200 /* get the next pointer before freeing */
screamer 0:7a64fbb4069d 201 p = iprh->next_pbuf;
screamer 0:7a64fbb4069d 202 pbufs_freed += pbuf_clen(pcur);
screamer 0:7a64fbb4069d 203 pbuf_free(pcur);
screamer 0:7a64fbb4069d 204 }
screamer 0:7a64fbb4069d 205 /* Then, unchain the struct ip_reassdata from the list and free it. */
screamer 0:7a64fbb4069d 206 ip_reass_dequeue_datagram(ipr, prev);
screamer 0:7a64fbb4069d 207 LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= pbufs_freed);
screamer 0:7a64fbb4069d 208 ip_reass_pbufcount -= pbufs_freed;
screamer 0:7a64fbb4069d 209
screamer 0:7a64fbb4069d 210 return pbufs_freed;
screamer 0:7a64fbb4069d 211 }
screamer 0:7a64fbb4069d 212
screamer 0:7a64fbb4069d 213 #if IP_REASS_FREE_OLDEST
screamer 0:7a64fbb4069d 214 /**
screamer 0:7a64fbb4069d 215 * Free the oldest datagram to make room for enqueueing new fragments.
screamer 0:7a64fbb4069d 216 * The datagram 'fraghdr' belongs to is not freed!
screamer 0:7a64fbb4069d 217 *
screamer 0:7a64fbb4069d 218 * @param fraghdr IP header of the current fragment
screamer 0:7a64fbb4069d 219 * @param pbufs_needed number of pbufs needed to enqueue
screamer 0:7a64fbb4069d 220 * (used for freeing other datagrams if not enough space)
screamer 0:7a64fbb4069d 221 * @return the number of pbufs freed
screamer 0:7a64fbb4069d 222 */
screamer 0:7a64fbb4069d 223 static int
screamer 0:7a64fbb4069d 224 ip_reass_remove_oldest_datagram(struct ip_hdr *fraghdr, int pbufs_needed)
screamer 0:7a64fbb4069d 225 {
screamer 0:7a64fbb4069d 226 /* @todo Can't we simply remove the last datagram in the
screamer 0:7a64fbb4069d 227 * linked list behind reassdatagrams?
screamer 0:7a64fbb4069d 228 */
screamer 0:7a64fbb4069d 229 struct ip_reassdata *r, *oldest, *prev;
screamer 0:7a64fbb4069d 230 int pbufs_freed = 0, pbufs_freed_current;
screamer 0:7a64fbb4069d 231 int other_datagrams;
screamer 0:7a64fbb4069d 232
screamer 0:7a64fbb4069d 233 /* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
screamer 0:7a64fbb4069d 234 * but don't free the datagram that 'fraghdr' belongs to! */
screamer 0:7a64fbb4069d 235 do {
screamer 0:7a64fbb4069d 236 oldest = NULL;
screamer 0:7a64fbb4069d 237 prev = NULL;
screamer 0:7a64fbb4069d 238 other_datagrams = 0;
screamer 0:7a64fbb4069d 239 r = reassdatagrams;
screamer 0:7a64fbb4069d 240 while (r != NULL) {
screamer 0:7a64fbb4069d 241 if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) {
screamer 0:7a64fbb4069d 242 /* Not the same datagram as fraghdr */
screamer 0:7a64fbb4069d 243 other_datagrams++;
screamer 0:7a64fbb4069d 244 if (oldest == NULL) {
screamer 0:7a64fbb4069d 245 oldest = r;
screamer 0:7a64fbb4069d 246 } else if (r->timer <= oldest->timer) {
screamer 0:7a64fbb4069d 247 /* older than the previous oldest */
screamer 0:7a64fbb4069d 248 oldest = r;
screamer 0:7a64fbb4069d 249 }
screamer 0:7a64fbb4069d 250 }
screamer 0:7a64fbb4069d 251 if (r->next != NULL) {
screamer 0:7a64fbb4069d 252 prev = r;
screamer 0:7a64fbb4069d 253 }
screamer 0:7a64fbb4069d 254 r = r->next;
screamer 0:7a64fbb4069d 255 }
screamer 0:7a64fbb4069d 256 if (oldest != NULL) {
screamer 0:7a64fbb4069d 257 pbufs_freed_current = ip_reass_free_complete_datagram(oldest, prev);
screamer 0:7a64fbb4069d 258 pbufs_freed += pbufs_freed_current;
screamer 0:7a64fbb4069d 259 }
screamer 0:7a64fbb4069d 260 } while ((pbufs_freed < pbufs_needed) && (other_datagrams > 1));
screamer 0:7a64fbb4069d 261 return pbufs_freed;
screamer 0:7a64fbb4069d 262 }
screamer 0:7a64fbb4069d 263 #endif /* IP_REASS_FREE_OLDEST */
screamer 0:7a64fbb4069d 264
screamer 0:7a64fbb4069d 265 /**
screamer 0:7a64fbb4069d 266 * Enqueues a new fragment into the fragment queue
screamer 0:7a64fbb4069d 267 * @param fraghdr points to the new fragments IP hdr
screamer 0:7a64fbb4069d 268 * @param clen number of pbufs needed to enqueue (used for freeing other datagrams if not enough space)
screamer 0:7a64fbb4069d 269 * @return A pointer to the queue location into which the fragment was enqueued
screamer 0:7a64fbb4069d 270 */
screamer 0:7a64fbb4069d 271 static struct ip_reassdata*
screamer 0:7a64fbb4069d 272 ip_reass_enqueue_new_datagram(struct ip_hdr *fraghdr, int clen)
screamer 0:7a64fbb4069d 273 {
screamer 0:7a64fbb4069d 274 struct ip_reassdata* ipr;
screamer 0:7a64fbb4069d 275 /* No matching previous fragment found, allocate a new reassdata struct */
screamer 0:7a64fbb4069d 276 ipr = (struct ip_reassdata *)(memp_malloc(MEMP_REASSDATA)); // static_cast<struct ip_reassdata *>(x)
screamer 0:7a64fbb4069d 277 if (ipr == NULL) {
screamer 0:7a64fbb4069d 278 #if IP_REASS_FREE_OLDEST
screamer 0:7a64fbb4069d 279 if (ip_reass_remove_oldest_datagram(fraghdr, clen) >= clen) {
screamer 0:7a64fbb4069d 280 ipr = (struct ip_reassdata *)(memp_malloc(MEMP_REASSDATA)); // static_cast<struct ip_reassdata *>(x)
screamer 0:7a64fbb4069d 281 }
screamer 0:7a64fbb4069d 282 if (ipr == NULL)
screamer 0:7a64fbb4069d 283 #endif /* IP_REASS_FREE_OLDEST */
screamer 0:7a64fbb4069d 284 {
screamer 0:7a64fbb4069d 285 IPFRAG_STATS_INC(ip_frag.memerr);
screamer 0:7a64fbb4069d 286 LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct\n"));
screamer 0:7a64fbb4069d 287 return NULL;
screamer 0:7a64fbb4069d 288 }
screamer 0:7a64fbb4069d 289 }
screamer 0:7a64fbb4069d 290 memset(ipr, 0, sizeof(struct ip_reassdata));
screamer 0:7a64fbb4069d 291 ipr->timer = IP_REASS_MAXAGE;
screamer 0:7a64fbb4069d 292
screamer 0:7a64fbb4069d 293 /* enqueue the new structure to the front of the list */
screamer 0:7a64fbb4069d 294 ipr->next = reassdatagrams;
screamer 0:7a64fbb4069d 295 reassdatagrams = ipr;
screamer 0:7a64fbb4069d 296 /* copy the ip header for later tests and input */
screamer 0:7a64fbb4069d 297 /* @todo: no ip options supported? */
screamer 0:7a64fbb4069d 298 SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN);
screamer 0:7a64fbb4069d 299 return ipr;
screamer 0:7a64fbb4069d 300 }
screamer 0:7a64fbb4069d 301
screamer 0:7a64fbb4069d 302 /**
screamer 0:7a64fbb4069d 303 * Dequeues a datagram from the datagram queue. Doesn't deallocate the pbufs.
screamer 0:7a64fbb4069d 304 * @param ipr points to the queue entry to dequeue
screamer 0:7a64fbb4069d 305 */
screamer 0:7a64fbb4069d 306 static void
screamer 0:7a64fbb4069d 307 ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
screamer 0:7a64fbb4069d 308 {
screamer 0:7a64fbb4069d 309
screamer 0:7a64fbb4069d 310 /* dequeue the reass struct */
screamer 0:7a64fbb4069d 311 if (reassdatagrams == ipr) {
screamer 0:7a64fbb4069d 312 /* it was the first in the list */
screamer 0:7a64fbb4069d 313 reassdatagrams = ipr->next;
screamer 0:7a64fbb4069d 314 } else {
screamer 0:7a64fbb4069d 315 /* it wasn't the first, so it must have a valid 'prev' */
screamer 0:7a64fbb4069d 316 LWIP_ASSERT("sanity check linked list", prev != NULL);
screamer 0:7a64fbb4069d 317 prev->next = ipr->next;
screamer 0:7a64fbb4069d 318 }
screamer 0:7a64fbb4069d 319
screamer 0:7a64fbb4069d 320 /* now we can free the ip_reass struct */
screamer 0:7a64fbb4069d 321 memp_free(MEMP_REASSDATA, ipr);
screamer 0:7a64fbb4069d 322 }
screamer 0:7a64fbb4069d 323
screamer 0:7a64fbb4069d 324 /**
screamer 0:7a64fbb4069d 325 * Chain a new pbuf into the pbuf list that composes the datagram. The pbuf list
screamer 0:7a64fbb4069d 326 * will grow over time as new pbufs are rx.
screamer 0:7a64fbb4069d 327 * Also checks that the datagram passes basic continuity checks (if the last
screamer 0:7a64fbb4069d 328 * fragment was received at least once).
screamer 0:7a64fbb4069d 329 * @param root_p points to the 'root' pbuf for the current datagram being assembled.
screamer 0:7a64fbb4069d 330 * @param new_p points to the pbuf for the current fragment
screamer 0:7a64fbb4069d 331 * @return 0 if invalid, >0 otherwise
screamer 0:7a64fbb4069d 332 */
screamer 0:7a64fbb4069d 333 static int
screamer 0:7a64fbb4069d 334 ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata *ipr, struct pbuf *new_p)
screamer 0:7a64fbb4069d 335 {
screamer 0:7a64fbb4069d 336 struct ip_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
screamer 0:7a64fbb4069d 337 struct pbuf *q;
screamer 0:7a64fbb4069d 338 u16_t offset,len;
screamer 0:7a64fbb4069d 339 struct ip_hdr *fraghdr;
screamer 0:7a64fbb4069d 340 int valid = 1;
screamer 0:7a64fbb4069d 341
screamer 0:7a64fbb4069d 342 /* Extract length and fragment offset from current fragment */
screamer 0:7a64fbb4069d 343 fraghdr = (struct ip_hdr*)new_p->payload;
screamer 0:7a64fbb4069d 344 len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
screamer 0:7a64fbb4069d 345 offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
screamer 0:7a64fbb4069d 346
screamer 0:7a64fbb4069d 347 /* overwrite the fragment's ip header from the pbuf with our helper struct,
screamer 0:7a64fbb4069d 348 * and setup the embedded helper structure. */
screamer 0:7a64fbb4069d 349 /* make sure the struct ip_reass_helper fits into the IP header */
screamer 0:7a64fbb4069d 350 LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN",
screamer 0:7a64fbb4069d 351 sizeof(struct ip_reass_helper) <= IP_HLEN);
screamer 0:7a64fbb4069d 352 iprh = (struct ip_reass_helper*)new_p->payload;
screamer 0:7a64fbb4069d 353 iprh->next_pbuf = NULL;
screamer 0:7a64fbb4069d 354 iprh->start = offset;
screamer 0:7a64fbb4069d 355 iprh->end = offset + len;
screamer 0:7a64fbb4069d 356
screamer 0:7a64fbb4069d 357 /* Iterate through until we either get to the end of the list (append),
screamer 0:7a64fbb4069d 358 * or we find on with a larger offset (insert). */
screamer 0:7a64fbb4069d 359 for (q = ipr->p; q != NULL;) {
screamer 0:7a64fbb4069d 360 iprh_tmp = (struct ip_reass_helper*)q->payload;
screamer 0:7a64fbb4069d 361 if (iprh->start < iprh_tmp->start) {
screamer 0:7a64fbb4069d 362 /* the new pbuf should be inserted before this */
screamer 0:7a64fbb4069d 363 iprh->next_pbuf = q;
screamer 0:7a64fbb4069d 364 if (iprh_prev != NULL) {
screamer 0:7a64fbb4069d 365 /* not the fragment with the lowest offset */
screamer 0:7a64fbb4069d 366 #if IP_REASS_CHECK_OVERLAP
screamer 0:7a64fbb4069d 367 if ((iprh->start < iprh_prev->end) || (iprh->end > iprh_tmp->start)) {
screamer 0:7a64fbb4069d 368 /* fragment overlaps with previous or following, throw away */
screamer 0:7a64fbb4069d 369 goto freepbuf;
screamer 0:7a64fbb4069d 370 }
screamer 0:7a64fbb4069d 371 #endif /* IP_REASS_CHECK_OVERLAP */
screamer 0:7a64fbb4069d 372 iprh_prev->next_pbuf = new_p;
screamer 0:7a64fbb4069d 373 } else {
screamer 0:7a64fbb4069d 374 /* fragment with the lowest offset */
screamer 0:7a64fbb4069d 375 ipr->p = new_p;
screamer 0:7a64fbb4069d 376 }
screamer 0:7a64fbb4069d 377 break;
screamer 0:7a64fbb4069d 378 } else if(iprh->start == iprh_tmp->start) {
screamer 0:7a64fbb4069d 379 /* received the same datagram twice: no need to keep the datagram */
screamer 0:7a64fbb4069d 380 goto freepbuf;
screamer 0:7a64fbb4069d 381 #if IP_REASS_CHECK_OVERLAP
screamer 0:7a64fbb4069d 382 } else if(iprh->start < iprh_tmp->end) {
screamer 0:7a64fbb4069d 383 /* overlap: no need to keep the new datagram */
screamer 0:7a64fbb4069d 384 goto freepbuf;
screamer 0:7a64fbb4069d 385 #endif /* IP_REASS_CHECK_OVERLAP */
screamer 0:7a64fbb4069d 386 } else {
screamer 0:7a64fbb4069d 387 /* Check if the fragments received so far have no wholes. */
screamer 0:7a64fbb4069d 388 if (iprh_prev != NULL) {
screamer 0:7a64fbb4069d 389 if (iprh_prev->end != iprh_tmp->start) {
screamer 0:7a64fbb4069d 390 /* There is a fragment missing between the current
screamer 0:7a64fbb4069d 391 * and the previous fragment */
screamer 0:7a64fbb4069d 392 valid = 0;
screamer 0:7a64fbb4069d 393 }
screamer 0:7a64fbb4069d 394 }
screamer 0:7a64fbb4069d 395 }
screamer 0:7a64fbb4069d 396 q = iprh_tmp->next_pbuf;
screamer 0:7a64fbb4069d 397 iprh_prev = iprh_tmp;
screamer 0:7a64fbb4069d 398 }
screamer 0:7a64fbb4069d 399
screamer 0:7a64fbb4069d 400 /* If q is NULL, then we made it to the end of the list. Determine what to do now */
screamer 0:7a64fbb4069d 401 if (q == NULL) {
screamer 0:7a64fbb4069d 402 if (iprh_prev != NULL) {
screamer 0:7a64fbb4069d 403 /* this is (for now), the fragment with the highest offset:
screamer 0:7a64fbb4069d 404 * chain it to the last fragment */
screamer 0:7a64fbb4069d 405 #if IP_REASS_CHECK_OVERLAP
screamer 0:7a64fbb4069d 406 LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
screamer 0:7a64fbb4069d 407 #endif /* IP_REASS_CHECK_OVERLAP */
screamer 0:7a64fbb4069d 408 iprh_prev->next_pbuf = new_p;
screamer 0:7a64fbb4069d 409 if (iprh_prev->end != iprh->start) {
screamer 0:7a64fbb4069d 410 valid = 0;
screamer 0:7a64fbb4069d 411 }
screamer 0:7a64fbb4069d 412 } else {
screamer 0:7a64fbb4069d 413 #if IP_REASS_CHECK_OVERLAP
screamer 0:7a64fbb4069d 414 LWIP_ASSERT("no previous fragment, this must be the first fragment!",
screamer 0:7a64fbb4069d 415 ipr->p == NULL);
screamer 0:7a64fbb4069d 416 #endif /* IP_REASS_CHECK_OVERLAP */
screamer 0:7a64fbb4069d 417 /* this is the first fragment we ever received for this ip datagram */
screamer 0:7a64fbb4069d 418 ipr->p = new_p;
screamer 0:7a64fbb4069d 419 }
screamer 0:7a64fbb4069d 420 }
screamer 0:7a64fbb4069d 421
screamer 0:7a64fbb4069d 422 /* At this point, the validation part begins: */
screamer 0:7a64fbb4069d 423 /* If we already received the last fragment */
screamer 0:7a64fbb4069d 424 if ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0) {
screamer 0:7a64fbb4069d 425 /* and had no wholes so far */
screamer 0:7a64fbb4069d 426 if (valid) {
screamer 0:7a64fbb4069d 427 /* then check if the rest of the fragments is here */
screamer 0:7a64fbb4069d 428 /* Check if the queue starts with the first datagram */
screamer 0:7a64fbb4069d 429 if (((struct ip_reass_helper*)ipr->p->payload)->start != 0) {
screamer 0:7a64fbb4069d 430 valid = 0;
screamer 0:7a64fbb4069d 431 } else {
screamer 0:7a64fbb4069d 432 /* and check that there are no wholes after this datagram */
screamer 0:7a64fbb4069d 433 iprh_prev = iprh;
screamer 0:7a64fbb4069d 434 q = iprh->next_pbuf;
screamer 0:7a64fbb4069d 435 while (q != NULL) {
screamer 0:7a64fbb4069d 436 iprh = (struct ip_reass_helper*)q->payload;
screamer 0:7a64fbb4069d 437 if (iprh_prev->end != iprh->start) {
screamer 0:7a64fbb4069d 438 valid = 0;
screamer 0:7a64fbb4069d 439 break;
screamer 0:7a64fbb4069d 440 }
screamer 0:7a64fbb4069d 441 iprh_prev = iprh;
screamer 0:7a64fbb4069d 442 q = iprh->next_pbuf;
screamer 0:7a64fbb4069d 443 }
screamer 0:7a64fbb4069d 444 /* if still valid, all fragments are received
screamer 0:7a64fbb4069d 445 * (because to the MF==0 already arrived */
screamer 0:7a64fbb4069d 446 if (valid) {
screamer 0:7a64fbb4069d 447 LWIP_ASSERT("sanity check", ipr->p != NULL);
screamer 0:7a64fbb4069d 448 LWIP_ASSERT("sanity check",
screamer 0:7a64fbb4069d 449 ((struct ip_reass_helper*)ipr->p->payload) != iprh);
screamer 0:7a64fbb4069d 450 LWIP_ASSERT("validate_datagram:next_pbuf!=NULL",
screamer 0:7a64fbb4069d 451 iprh->next_pbuf == NULL);
screamer 0:7a64fbb4069d 452 LWIP_ASSERT("validate_datagram:datagram end!=datagram len",
screamer 0:7a64fbb4069d 453 iprh->end == ipr->datagram_len);
screamer 0:7a64fbb4069d 454 }
screamer 0:7a64fbb4069d 455 }
screamer 0:7a64fbb4069d 456 }
screamer 0:7a64fbb4069d 457 /* If valid is 0 here, there are some fragments missing in the middle
screamer 0:7a64fbb4069d 458 * (since MF == 0 has already arrived). Such datagrams simply time out if
screamer 0:7a64fbb4069d 459 * no more fragments are received... */
screamer 0:7a64fbb4069d 460 return valid;
screamer 0:7a64fbb4069d 461 }
screamer 0:7a64fbb4069d 462 /* If we come here, not all fragments were received, yet! */
screamer 0:7a64fbb4069d 463 return 0; /* not yet valid! */
screamer 0:7a64fbb4069d 464 #if IP_REASS_CHECK_OVERLAP
screamer 0:7a64fbb4069d 465 freepbuf:
screamer 0:7a64fbb4069d 466 ip_reass_pbufcount -= pbuf_clen(new_p);
screamer 0:7a64fbb4069d 467 pbuf_free(new_p);
screamer 0:7a64fbb4069d 468 return 0;
screamer 0:7a64fbb4069d 469 #endif /* IP_REASS_CHECK_OVERLAP */
screamer 0:7a64fbb4069d 470 }
screamer 0:7a64fbb4069d 471
screamer 0:7a64fbb4069d 472 /**
screamer 0:7a64fbb4069d 473 * Reassembles incoming IP fragments into an IP datagram.
screamer 0:7a64fbb4069d 474 *
screamer 0:7a64fbb4069d 475 * @param p points to a pbuf chain of the fragment
screamer 0:7a64fbb4069d 476 * @return NULL if reassembly is incomplete, ? otherwise
screamer 0:7a64fbb4069d 477 */
screamer 0:7a64fbb4069d 478 struct pbuf *
screamer 0:7a64fbb4069d 479 ip_reass(struct pbuf *p)
screamer 0:7a64fbb4069d 480 {
screamer 0:7a64fbb4069d 481 struct pbuf *r;
screamer 0:7a64fbb4069d 482 struct ip_hdr *fraghdr;
screamer 0:7a64fbb4069d 483 struct ip_reassdata *ipr;
screamer 0:7a64fbb4069d 484 struct ip_reass_helper *iprh;
screamer 0:7a64fbb4069d 485 u16_t offset, len;
screamer 0:7a64fbb4069d 486 u8_t clen;
screamer 0:7a64fbb4069d 487 struct ip_reassdata *ipr_prev = NULL;
screamer 0:7a64fbb4069d 488
screamer 0:7a64fbb4069d 489 IPFRAG_STATS_INC(ip_frag.recv);
screamer 0:7a64fbb4069d 490 snmp_inc_ipreasmreqds();
screamer 0:7a64fbb4069d 491
screamer 0:7a64fbb4069d 492 fraghdr = (struct ip_hdr*)p->payload;
screamer 0:7a64fbb4069d 493
screamer 0:7a64fbb4069d 494 if ((IPH_HL(fraghdr) * 4) != IP_HLEN) {
screamer 0:7a64fbb4069d 495 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n"));
screamer 0:7a64fbb4069d 496 IPFRAG_STATS_INC(ip_frag.err);
screamer 0:7a64fbb4069d 497 goto nullreturn;
screamer 0:7a64fbb4069d 498 }
screamer 0:7a64fbb4069d 499
screamer 0:7a64fbb4069d 500 offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8;
screamer 0:7a64fbb4069d 501 len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4;
screamer 0:7a64fbb4069d 502
screamer 0:7a64fbb4069d 503 /* Check if we are allowed to enqueue more datagrams. */
screamer 0:7a64fbb4069d 504 clen = pbuf_clen(p);
screamer 0:7a64fbb4069d 505 if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
screamer 0:7a64fbb4069d 506 #if IP_REASS_FREE_OLDEST
screamer 0:7a64fbb4069d 507 if (!ip_reass_remove_oldest_datagram(fraghdr, clen) ||
screamer 0:7a64fbb4069d 508 ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
screamer 0:7a64fbb4069d 509 #endif /* IP_REASS_FREE_OLDEST */
screamer 0:7a64fbb4069d 510 {
screamer 0:7a64fbb4069d 511 /* No datagram could be freed and still too many pbufs enqueued */
screamer 0:7a64fbb4069d 512 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
screamer 0:7a64fbb4069d 513 ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
screamer 0:7a64fbb4069d 514 IPFRAG_STATS_INC(ip_frag.memerr);
screamer 0:7a64fbb4069d 515 /* @todo: send ICMP time exceeded here? */
screamer 0:7a64fbb4069d 516 /* drop this pbuf */
screamer 0:7a64fbb4069d 517 goto nullreturn;
screamer 0:7a64fbb4069d 518 }
screamer 0:7a64fbb4069d 519 }
screamer 0:7a64fbb4069d 520
screamer 0:7a64fbb4069d 521 /* Look for the datagram the fragment belongs to in the current datagram queue,
screamer 0:7a64fbb4069d 522 * remembering the previous in the queue for later dequeueing. */
screamer 0:7a64fbb4069d 523 for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
screamer 0:7a64fbb4069d 524 /* Check if the incoming fragment matches the one currently present
screamer 0:7a64fbb4069d 525 in the reassembly buffer. If so, we proceed with copying the
screamer 0:7a64fbb4069d 526 fragment into the buffer. */
screamer 0:7a64fbb4069d 527 if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
screamer 0:7a64fbb4069d 528 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n",
screamer 0:7a64fbb4069d 529 ntohs(IPH_ID(fraghdr))));
screamer 0:7a64fbb4069d 530 IPFRAG_STATS_INC(ip_frag.cachehit);
screamer 0:7a64fbb4069d 531 break;
screamer 0:7a64fbb4069d 532 }
screamer 0:7a64fbb4069d 533 ipr_prev = ipr;
screamer 0:7a64fbb4069d 534 }
screamer 0:7a64fbb4069d 535
screamer 0:7a64fbb4069d 536 if (ipr == NULL) {
screamer 0:7a64fbb4069d 537 /* Enqueue a new datagram into the datagram queue */
screamer 0:7a64fbb4069d 538 ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
screamer 0:7a64fbb4069d 539 /* Bail if unable to enqueue */
screamer 0:7a64fbb4069d 540 if(ipr == NULL) {
screamer 0:7a64fbb4069d 541 goto nullreturn;
screamer 0:7a64fbb4069d 542 }
screamer 0:7a64fbb4069d 543 } else {
screamer 0:7a64fbb4069d 544 if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) &&
screamer 0:7a64fbb4069d 545 ((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
screamer 0:7a64fbb4069d 546 /* ipr->iphdr is not the header from the first fragment, but fraghdr is
screamer 0:7a64fbb4069d 547 * -> copy fraghdr into ipr->iphdr since we want to have the header
screamer 0:7a64fbb4069d 548 * of the first fragment (for ICMP time exceeded and later, for copying
screamer 0:7a64fbb4069d 549 * all options, if supported)*/
screamer 0:7a64fbb4069d 550 SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
screamer 0:7a64fbb4069d 551 }
screamer 0:7a64fbb4069d 552 }
screamer 0:7a64fbb4069d 553 /* Track the current number of pbufs current 'in-flight', in order to limit
screamer 0:7a64fbb4069d 554 the number of fragments that may be enqueued at any one time */
screamer 0:7a64fbb4069d 555 ip_reass_pbufcount += clen;
screamer 0:7a64fbb4069d 556
screamer 0:7a64fbb4069d 557 /* At this point, we have either created a new entry or pointing
screamer 0:7a64fbb4069d 558 * to an existing one */
screamer 0:7a64fbb4069d 559
screamer 0:7a64fbb4069d 560 /* check for 'no more fragments', and update queue entry*/
screamer 0:7a64fbb4069d 561 if ((ntohs(IPH_OFFSET(fraghdr)) & IP_MF) == 0) {
screamer 0:7a64fbb4069d 562 ipr->flags |= IP_REASS_FLAG_LASTFRAG;
screamer 0:7a64fbb4069d 563 ipr->datagram_len = offset + len;
screamer 0:7a64fbb4069d 564 LWIP_DEBUGF(IP_REASS_DEBUG,
screamer 0:7a64fbb4069d 565 ("ip_reass: last fragment seen, total len %"S16_F"\n",
screamer 0:7a64fbb4069d 566 ipr->datagram_len));
screamer 0:7a64fbb4069d 567 }
screamer 0:7a64fbb4069d 568 /* find the right place to insert this pbuf */
screamer 0:7a64fbb4069d 569 /* @todo: trim pbufs if fragments are overlapping */
screamer 0:7a64fbb4069d 570 if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) {
screamer 0:7a64fbb4069d 571 /* the totally last fragment (flag more fragments = 0) was received at least
screamer 0:7a64fbb4069d 572 * once AND all fragments are received */
screamer 0:7a64fbb4069d 573 ipr->datagram_len += IP_HLEN;
screamer 0:7a64fbb4069d 574
screamer 0:7a64fbb4069d 575 /* save the second pbuf before copying the header over the pointer */
screamer 0:7a64fbb4069d 576 r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf;
screamer 0:7a64fbb4069d 577
screamer 0:7a64fbb4069d 578 /* copy the original ip header back to the first pbuf */
screamer 0:7a64fbb4069d 579 fraghdr = (struct ip_hdr*)(ipr->p->payload);
screamer 0:7a64fbb4069d 580 SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
screamer 0:7a64fbb4069d 581 IPH_LEN_SET(fraghdr, htons(ipr->datagram_len));
screamer 0:7a64fbb4069d 582 IPH_OFFSET_SET(fraghdr, 0);
screamer 0:7a64fbb4069d 583 IPH_CHKSUM_SET(fraghdr, 0);
screamer 0:7a64fbb4069d 584 /* @todo: do we need to set calculate the correct checksum? */
screamer 0:7a64fbb4069d 585 IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));
screamer 0:7a64fbb4069d 586
screamer 0:7a64fbb4069d 587 p = ipr->p;
screamer 0:7a64fbb4069d 588
screamer 0:7a64fbb4069d 589 /* chain together the pbufs contained within the reass_data list. */
screamer 0:7a64fbb4069d 590 while(r != NULL) {
screamer 0:7a64fbb4069d 591 iprh = (struct ip_reass_helper*)r->payload;
screamer 0:7a64fbb4069d 592
screamer 0:7a64fbb4069d 593 /* hide the ip header for every succeding fragment */
screamer 0:7a64fbb4069d 594 pbuf_header(r, -IP_HLEN);
screamer 0:7a64fbb4069d 595 pbuf_cat(p, r);
screamer 0:7a64fbb4069d 596 r = iprh->next_pbuf;
screamer 0:7a64fbb4069d 597 }
screamer 0:7a64fbb4069d 598 /* release the sources allocate for the fragment queue entry */
screamer 0:7a64fbb4069d 599 ip_reass_dequeue_datagram(ipr, ipr_prev);
screamer 0:7a64fbb4069d 600
screamer 0:7a64fbb4069d 601 /* and adjust the number of pbufs currently queued for reassembly. */
screamer 0:7a64fbb4069d 602 ip_reass_pbufcount -= pbuf_clen(p);
screamer 0:7a64fbb4069d 603
screamer 0:7a64fbb4069d 604 /* Return the pbuf chain */
screamer 0:7a64fbb4069d 605 return p;
screamer 0:7a64fbb4069d 606 }
screamer 0:7a64fbb4069d 607 /* the datagram is not (yet?) reassembled completely */
screamer 0:7a64fbb4069d 608 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
screamer 0:7a64fbb4069d 609 return NULL;
screamer 0:7a64fbb4069d 610
screamer 0:7a64fbb4069d 611 nullreturn:
screamer 0:7a64fbb4069d 612 LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n"));
screamer 0:7a64fbb4069d 613 IPFRAG_STATS_INC(ip_frag.drop);
screamer 0:7a64fbb4069d 614 pbuf_free(p);
screamer 0:7a64fbb4069d 615 return NULL;
screamer 0:7a64fbb4069d 616 }
screamer 0:7a64fbb4069d 617 #endif /* IP_REASSEMBLY */
screamer 0:7a64fbb4069d 618
screamer 0:7a64fbb4069d 619 #if IP_FRAG
screamer 0:7a64fbb4069d 620 #if IP_FRAG_USES_STATIC_BUF
screamer 0:7a64fbb4069d 621 static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU + MEM_ALIGNMENT - 1)];
screamer 0:7a64fbb4069d 622 #endif /* IP_FRAG_USES_STATIC_BUF */
screamer 0:7a64fbb4069d 623
screamer 0:7a64fbb4069d 624 /**
screamer 0:7a64fbb4069d 625 * Fragment an IP datagram if too large for the netif.
screamer 0:7a64fbb4069d 626 *
screamer 0:7a64fbb4069d 627 * Chop the datagram in MTU sized chunks and send them in order
screamer 0:7a64fbb4069d 628 * by using a fixed size static memory buffer (PBUF_REF) or
screamer 0:7a64fbb4069d 629 * point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF).
screamer 0:7a64fbb4069d 630 *
screamer 0:7a64fbb4069d 631 * @param p ip packet to send
screamer 0:7a64fbb4069d 632 * @param netif the netif on which to send
screamer 0:7a64fbb4069d 633 * @param dest destination ip address to which to send
screamer 0:7a64fbb4069d 634 *
screamer 0:7a64fbb4069d 635 * @return ERR_OK if sent successfully, err_t otherwise
screamer 0:7a64fbb4069d 636 */
screamer 0:7a64fbb4069d 637 err_t
screamer 0:7a64fbb4069d 638 ip_frag(struct pbuf *p, struct netif *netif, struct ip_addr *dest)
screamer 0:7a64fbb4069d 639 {
screamer 0:7a64fbb4069d 640 struct pbuf *rambuf;
screamer 0:7a64fbb4069d 641 #if IP_FRAG_USES_STATIC_BUF
screamer 0:7a64fbb4069d 642 struct pbuf *header;
screamer 0:7a64fbb4069d 643 #else
screamer 0:7a64fbb4069d 644 struct pbuf *newpbuf;
screamer 0:7a64fbb4069d 645 struct ip_hdr *original_iphdr;
screamer 0:7a64fbb4069d 646 #endif
screamer 0:7a64fbb4069d 647 struct ip_hdr *iphdr;
screamer 0:7a64fbb4069d 648 u16_t nfb;
screamer 0:7a64fbb4069d 649 u16_t left, cop;
screamer 0:7a64fbb4069d 650 u16_t mtu = netif->mtu;
screamer 0:7a64fbb4069d 651 u16_t ofo, omf;
screamer 0:7a64fbb4069d 652 u16_t last;
screamer 0:7a64fbb4069d 653 u16_t poff = IP_HLEN;
screamer 0:7a64fbb4069d 654 u16_t tmp;
screamer 0:7a64fbb4069d 655 #if !IP_FRAG_USES_STATIC_BUF
screamer 0:7a64fbb4069d 656 u16_t newpbuflen = 0;
screamer 0:7a64fbb4069d 657 u16_t left_to_copy;
screamer 0:7a64fbb4069d 658 #endif
screamer 0:7a64fbb4069d 659
screamer 0:7a64fbb4069d 660 /* Get a RAM based MTU sized pbuf */
screamer 0:7a64fbb4069d 661 #if IP_FRAG_USES_STATIC_BUF
screamer 0:7a64fbb4069d 662 /* When using a static buffer, we use a PBUF_REF, which we will
screamer 0:7a64fbb4069d 663 * use to reference the packet (without link header).
screamer 0:7a64fbb4069d 664 * Layer and length is irrelevant.
screamer 0:7a64fbb4069d 665 */
screamer 0:7a64fbb4069d 666 rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF);
screamer 0:7a64fbb4069d 667 if (rambuf == NULL) {
screamer 0:7a64fbb4069d 668 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n"));
screamer 0:7a64fbb4069d 669 return ERR_MEM;
screamer 0:7a64fbb4069d 670 }
screamer 0:7a64fbb4069d 671 rambuf->tot_len = rambuf->len = mtu;
screamer 0:7a64fbb4069d 672 rambuf->payload = LWIP_MEM_ALIGN((void *)buf);
screamer 0:7a64fbb4069d 673
screamer 0:7a64fbb4069d 674 /* Copy the IP header in it */
screamer 0:7a64fbb4069d 675 iphdr = (struct ip_hdr *)(rambuf->payload); // static_cast<struct ip_hdr *>(x)
screamer 0:7a64fbb4069d 676 SMEMCPY(iphdr, p->payload, IP_HLEN);
screamer 0:7a64fbb4069d 677 #else /* IP_FRAG_USES_STATIC_BUF */
screamer 0:7a64fbb4069d 678 original_iphdr = (struct ip_hdr *)p->payload;
screamer 0:7a64fbb4069d 679 iphdr = original_iphdr;
screamer 0:7a64fbb4069d 680 #endif /* IP_FRAG_USES_STATIC_BUF */
screamer 0:7a64fbb4069d 681
screamer 0:7a64fbb4069d 682 /* Save original offset */
screamer 0:7a64fbb4069d 683 tmp = ntohs(IPH_OFFSET(iphdr));
screamer 0:7a64fbb4069d 684 ofo = tmp & IP_OFFMASK;
screamer 0:7a64fbb4069d 685 omf = tmp & IP_MF;
screamer 0:7a64fbb4069d 686
screamer 0:7a64fbb4069d 687 left = p->tot_len - IP_HLEN;
screamer 0:7a64fbb4069d 688
screamer 0:7a64fbb4069d 689 nfb = (mtu - IP_HLEN) / 8;
screamer 0:7a64fbb4069d 690
screamer 0:7a64fbb4069d 691 while (left) {
screamer 0:7a64fbb4069d 692 last = (left <= mtu - IP_HLEN);
screamer 0:7a64fbb4069d 693
screamer 0:7a64fbb4069d 694 /* Set new offset and MF flag */
screamer 0:7a64fbb4069d 695 tmp = omf | (IP_OFFMASK & (ofo));
screamer 0:7a64fbb4069d 696 if (!last)
screamer 0:7a64fbb4069d 697 tmp = tmp | IP_MF;
screamer 0:7a64fbb4069d 698
screamer 0:7a64fbb4069d 699 /* Fill this fragment */
screamer 0:7a64fbb4069d 700 cop = last ? left : nfb * 8;
screamer 0:7a64fbb4069d 701
screamer 0:7a64fbb4069d 702 #if IP_FRAG_USES_STATIC_BUF
screamer 0:7a64fbb4069d 703 poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff);
screamer 0:7a64fbb4069d 704 #else /* IP_FRAG_USES_STATIC_BUF */
screamer 0:7a64fbb4069d 705 /* When not using a static buffer, create a chain of pbufs.
screamer 0:7a64fbb4069d 706 * The first will be a PBUF_RAM holding the link and IP header.
screamer 0:7a64fbb4069d 707 * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
screamer 0:7a64fbb4069d 708 * but limited to the size of an mtu.
screamer 0:7a64fbb4069d 709 */
screamer 0:7a64fbb4069d 710 rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
screamer 0:7a64fbb4069d 711 if (rambuf == NULL) {
screamer 0:7a64fbb4069d 712 return ERR_MEM;
screamer 0:7a64fbb4069d 713 }
screamer 0:7a64fbb4069d 714 LWIP_ASSERT("this needs a pbuf in one piece!",
screamer 0:7a64fbb4069d 715 (p->len >= (IP_HLEN)));
screamer 0:7a64fbb4069d 716 SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
screamer 0:7a64fbb4069d 717 iphdr = (struct ip_hdr *)rambuf->payload;
screamer 0:7a64fbb4069d 718
screamer 0:7a64fbb4069d 719 /* Can just adjust p directly for needed offset. */
screamer 0:7a64fbb4069d 720 p->payload = (u8_t *)p->payload + poff;
screamer 0:7a64fbb4069d 721 p->len -= poff;
screamer 0:7a64fbb4069d 722
screamer 0:7a64fbb4069d 723 left_to_copy = cop;
screamer 0:7a64fbb4069d 724 while (left_to_copy) {
screamer 0:7a64fbb4069d 725 newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
screamer 0:7a64fbb4069d 726 /* Is this pbuf already empty? */
screamer 0:7a64fbb4069d 727 if (!newpbuflen) {
screamer 0:7a64fbb4069d 728 p = p->next;
screamer 0:7a64fbb4069d 729 continue;
screamer 0:7a64fbb4069d 730 }
screamer 0:7a64fbb4069d 731 newpbuf = pbuf_alloc(PBUF_RAW, 0, PBUF_REF);
screamer 0:7a64fbb4069d 732 if (newpbuf == NULL) {
screamer 0:7a64fbb4069d 733 pbuf_free(rambuf);
screamer 0:7a64fbb4069d 734 return ERR_MEM;
screamer 0:7a64fbb4069d 735 }
screamer 0:7a64fbb4069d 736 /* Mirror this pbuf, although we might not need all of it. */
screamer 0:7a64fbb4069d 737 newpbuf->payload = p->payload;
screamer 0:7a64fbb4069d 738 newpbuf->len = newpbuf->tot_len = newpbuflen;
screamer 0:7a64fbb4069d 739 /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
screamer 0:7a64fbb4069d 740 * so that it is removed when pbuf_dechain is later called on rambuf.
screamer 0:7a64fbb4069d 741 */
screamer 0:7a64fbb4069d 742 pbuf_cat(rambuf, newpbuf);
screamer 0:7a64fbb4069d 743 left_to_copy -= newpbuflen;
screamer 0:7a64fbb4069d 744 if (left_to_copy)
screamer 0:7a64fbb4069d 745 p = p->next;
screamer 0:7a64fbb4069d 746 }
screamer 0:7a64fbb4069d 747 poff = newpbuflen;
screamer 0:7a64fbb4069d 748 #endif /* IP_FRAG_USES_STATIC_BUF */
screamer 0:7a64fbb4069d 749
screamer 0:7a64fbb4069d 750 /* Correct header */
screamer 0:7a64fbb4069d 751 IPH_OFFSET_SET(iphdr, htons(tmp));
screamer 0:7a64fbb4069d 752 IPH_LEN_SET(iphdr, htons(cop + IP_HLEN));
screamer 0:7a64fbb4069d 753 IPH_CHKSUM_SET(iphdr, 0);
screamer 0:7a64fbb4069d 754 IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
screamer 0:7a64fbb4069d 755
screamer 0:7a64fbb4069d 756 #if IP_FRAG_USES_STATIC_BUF
screamer 0:7a64fbb4069d 757 if (last)
screamer 0:7a64fbb4069d 758 pbuf_realloc(rambuf, left + IP_HLEN);
screamer 0:7a64fbb4069d 759
screamer 0:7a64fbb4069d 760 /* This part is ugly: we alloc a RAM based pbuf for
screamer 0:7a64fbb4069d 761 * the link level header for each chunk and then
screamer 0:7a64fbb4069d 762 * free it.A PBUF_ROM style pbuf for which pbuf_header
screamer 0:7a64fbb4069d 763 * worked would make things simpler.
screamer 0:7a64fbb4069d 764 */
screamer 0:7a64fbb4069d 765 header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
screamer 0:7a64fbb4069d 766 if (header != NULL) {
screamer 0:7a64fbb4069d 767 pbuf_chain(header, rambuf);
screamer 0:7a64fbb4069d 768 netif->output(netif, header, dest);
screamer 0:7a64fbb4069d 769 IPFRAG_STATS_INC(ip_frag.xmit);
screamer 0:7a64fbb4069d 770 snmp_inc_ipfragcreates();
screamer 0:7a64fbb4069d 771 pbuf_free(header);
screamer 0:7a64fbb4069d 772 } else {
screamer 0:7a64fbb4069d 773 LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n"));
screamer 0:7a64fbb4069d 774 pbuf_free(rambuf);
screamer 0:7a64fbb4069d 775 return ERR_MEM;
screamer 0:7a64fbb4069d 776 }
screamer 0:7a64fbb4069d 777 #else /* IP_FRAG_USES_STATIC_BUF */
screamer 0:7a64fbb4069d 778 /* No need for separate header pbuf - we allowed room for it in rambuf
screamer 0:7a64fbb4069d 779 * when allocated.
screamer 0:7a64fbb4069d 780 */
screamer 0:7a64fbb4069d 781 netif->output(netif, rambuf, dest);
screamer 0:7a64fbb4069d 782 IPFRAG_STATS_INC(ip_frag.xmit);
screamer 0:7a64fbb4069d 783
screamer 0:7a64fbb4069d 784 /* Unfortunately we can't reuse rambuf - the hardware may still be
screamer 0:7a64fbb4069d 785 * using the buffer. Instead we free it (and the ensuing chain) and
screamer 0:7a64fbb4069d 786 * recreate it next time round the loop. If we're lucky the hardware
screamer 0:7a64fbb4069d 787 * will have already sent the packet, the free will really free, and
screamer 0:7a64fbb4069d 788 * there will be zero memory penalty.
screamer 0:7a64fbb4069d 789 */
screamer 0:7a64fbb4069d 790
screamer 0:7a64fbb4069d 791 pbuf_free(rambuf);
screamer 0:7a64fbb4069d 792 #endif /* IP_FRAG_USES_STATIC_BUF */
screamer 0:7a64fbb4069d 793 left -= cop;
screamer 0:7a64fbb4069d 794 ofo += nfb;
screamer 0:7a64fbb4069d 795 }
screamer 0:7a64fbb4069d 796 #if IP_FRAG_USES_STATIC_BUF
screamer 0:7a64fbb4069d 797 pbuf_free(rambuf);
screamer 0:7a64fbb4069d 798 #endif /* IP_FRAG_USES_STATIC_BUF */
screamer 0:7a64fbb4069d 799 snmp_inc_ipfragoks();
screamer 0:7a64fbb4069d 800 return ERR_OK;
screamer 0:7a64fbb4069d 801 }
screamer 0:7a64fbb4069d 802 #endif /* IP_FRAG */