FreeRTOS/Common/ethernet/lwIP_130/src/core/ipv4/inet_chksum.c

   1 /**
   2  * @file
   3  * Incluse internet checksum functions.
   4  *
   5  */
   6
   7 /*
   8  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without modification,
  12  * are permitted provided that the following conditions are met:
  13  *
  14  * 1. Redistributions of source code must retain the above copyright notice,
  15  *    this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright notice,
  17  *    this list of conditions and the following disclaimer in the documentation
  18  *    and/or other materials provided with the distribution.
  19  * 3. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  23  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  25  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  26  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  27  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  30  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  31  * OF SUCH DAMAGE.
  32  *
  33  * This file is part of the lwIP TCP/IP stack.
  34  *
  35  * Author: Adam Dunkels <adam@sics.se>
  36  *
  37  */
  38
  39 #include "lwip/opt.h"
  40
  41 #include "lwip/inet_chksum.h"
  42 #include "lwip/inet.h"
  43
  44 #include <string.h>
  45
  46 /* These are some reference implementations of the checksum algorithm, with the
  47  * aim of being simple, correct and fully portable. Checksumming is the
  48  * first thing you would want to optimize for your platform. If you create
  49  * your own version, link it in and in your cc.h put:
  50  *
  51  * #define LWIP_CHKSUM <your_checksum_routine>
  52  *
  53  * Or you can select from the implementations below by defining
  54  * LWIP_CHKSUM_ALGORITHM to 1, 2 or 3.
  55  */
  56
  57 #ifndef LWIP_CHKSUM
  58 # define LWIP_CHKSUM lwip_standard_chksum
  59 # ifndef LWIP_CHKSUM_ALGORITHM
  60 #  define LWIP_CHKSUM_ALGORITHM 1
  61 # endif
  62 #endif
  63 /* If none set: */
  64 #ifndef LWIP_CHKSUM_ALGORITHM
  65 # define LWIP_CHKSUM_ALGORITHM 0
  66 #endif
  67
  68 #if (LWIP_CHKSUM_ALGORITHM == 1) /* Version #1 */
  69 /**
  70  * lwip checksum
  71  *
  72  * @param dataptr points to start of data to be summed at any boundary
  73  * @param len length of data to be summed
  74  * @return host order (!) lwip checksum (non-inverted Internet sum)
  75  *
  76  * @note accumulator size limits summable length to 64k
  77  * @note host endianess is irrelevant (p3 RFC1071)
  78  */
  79 static u16_t
  80 lwip_standard_chksum(void *dataptr, u16_t len)
  81 {
  82   u32_t acc;
  83   u16_t src;
  84   u8_t *octetptr;
  85
  86   acc = 0;
  87   /* dataptr may be at odd or even addresses */
  88   octetptr = (u8_t*)dataptr;
  89   while (len > 1)
  90   {
  91     /* declare first octet as most significant
  92        thus assume network order, ignoring host order */
  93     src = (*octetptr) << 8;
  94     octetptr++;
  95     /* declare second octet as least significant */
  96     src |= (*octetptr);
  97     octetptr++;
  98     acc += src;
  99     len -= 2;
 100   }
 101   if (len > 0)
 102   {
 103     /* accumulate remaining octet */
 104     src = (*octetptr) << 8;
 105     acc += src;
 106   }
 107   /* add deferred carry bits */
 108   acc = (acc >> 16) + (acc & 0x0000ffffUL);
 109   if ((acc & 0xffff0000) != 0) {
 110     acc = (acc >> 16) + (acc & 0x0000ffffUL);
 111   }
 112   /* This maybe a little confusing: reorder sum using htons()
 113      instead of ntohs() since it has a little less call overhead.
 114      The caller must invert bits for Internet sum ! */
 115   return htons((u16_t)acc);
 116 }
 117 #endif
 118
 119 #if (LWIP_CHKSUM_ALGORITHM == 2) /* Alternative version #2 */
 120 /*
 121  * Curt McDowell
 122  * Broadcom Corp.
 123  * csm@broadcom.com
 124  *
 125  * IP checksum two bytes at a time with support for
 126  * unaligned buffer.
 127  * Works for len up to and including 0x20000.
 128  * by Curt McDowell, Broadcom Corp. 12/08/2005
 129  *
 130  * @param dataptr points to start of data to be summed at any boundary
 131  * @param len length of data to be summed
 132  * @return host order (!) lwip checksum (non-inverted Internet sum)
 133  */
 134
 135 static u16_t
 136 lwip_standard_chksum(void *dataptr, int len)
 137 {
 138   u8_t *pb = dataptr;
 139   u16_t *ps, t = 0;
 140   u32_t sum = 0;
 141   int odd = ((u32_t)pb & 1);
 142
 143   /* Get aligned to u16_t */
 144   if (odd && len > 0) {
 145     ((u8_t *)&t)[1] = *pb++;
 146     len--;
 147   }
 148
 149   /* Add the bulk of the data */
 150   ps = (u16_t *)pb;
 151   while (len > 1) {
 152     sum += *ps++;
 153     len -= 2;
 154   }
 155
 156   /* Consume left-over byte, if any */
 157   if (len > 0)
 158     ((u8_t *)&t)[0] = *(u8_t *)ps;;
 159
 160   /* Add end bytes */
 161   sum += t;
 162
 163   /*  Fold 32-bit sum to 16 bits */
 164   while ((sum >> 16) != 0)
 165     sum = (sum & 0xffff) + (sum >> 16);
 166
 167   /* Swap if alignment was odd */
 168   if (odd)
 169     sum = ((sum & 0xff) << 8) | ((sum & 0xff00) >> 8);
 170
 171   return sum;
 172 }
 173 #endif
 174
 175 #if (LWIP_CHKSUM_ALGORITHM == 3) /* Alternative version #3 */
 176 /**
 177  * An optimized checksum routine. Basically, it uses loop-unrolling on
 178  * the checksum loop, treating the head and tail bytes specially, whereas
 179  * the inner loop acts on 8 bytes at a time.
 180  *
 181  * @arg start of buffer to be checksummed. May be an odd byte address.
 182  * @len number of bytes in the buffer to be checksummed.
 183  * @return host order (!) lwip checksum (non-inverted Internet sum)
 184  *
 185  * by Curt McDowell, Broadcom Corp. December 8th, 2005
 186  */
 187
 188 static u16_t
 189 lwip_standard_chksum(void *dataptr, int len)
 190 {
 191   u8_t *pb = dataptr;
 192   u16_t *ps, t = 0;
 193   u32_t *pl;
 194   u32_t sum = 0, tmp;
 195   /* starts at odd byte address? */
 196   int odd = ((u32_t)pb & 1);
 197
 198   if (odd && len > 0) {
 199     ((u8_t *)&t)[1] = *pb++;
 200     len--;
 201   }
 202
 203   ps = (u16_t *)pb;
 204
 205   if (((u32_t)ps & 3) && len > 1) {
 206     sum += *ps++;
 207     len -= 2;
 208   }
 209
 210   pl = (u32_t *)ps;
 211
 212   while (len > 7)  {
 213     tmp = sum + *pl++;          /* ping */
 214     if (tmp < sum)
 215       tmp++;                    /* add back carry */
 216
 217     sum = tmp + *pl++;          /* pong */
 218     if (sum < tmp)
 219       sum++;                    /* add back carry */
 220
 221     len -= 8;
 222   }
 223
 224   /* make room in upper bits */
 225   sum = (sum >> 16) + (sum & 0xffff);
 226
 227   ps = (u16_t *)pl;
 228
 229   /* 16-bit aligned word remaining? */
 230   while (len > 1) {
 231     sum += *ps++;
 232     len -= 2;
 233   }
 234
 235   /* dangling tail byte remaining? */
 236   if (len > 0)                  /* include odd byte */
 237     ((u8_t *)&t)[0] = *(u8_t *)ps;
 238
 239   sum += t;                     /* add end bytes */
 240
 241   while ((sum >> 16) != 0)      /* combine halves */
 242     sum = (sum >> 16) + (sum & 0xffff);
 243
 244   if (odd)
 245     sum = ((sum & 0xff) << 8) | ((sum & 0xff00) >> 8);
 246
 247   return sum;
 248 }
 249 #endif
 250
 251 /* inet_chksum_pseudo:
 252  *
 253  * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
 254  * IP addresses are expected to be in network byte order.
 255  *
 256  * @param p chain of pbufs over that a checksum should be calculated (ip data part)
 257  * @param src source ip address (used for checksum of pseudo header)
 258  * @param dst destination ip address (used for checksum of pseudo header)
 259  * @param proto ip protocol (used for checksum of pseudo header)
 260  * @param proto_len length of the ip data part (used for checksum of pseudo header)
 261  * @return checksum (as u16_t) to be saved directly in the protocol header
 262  */
 263 u16_t
 264 inet_chksum_pseudo(struct pbuf *p,
 265        struct ip_addr *src, struct ip_addr *dest,
 266        u8_t proto, u16_t proto_len)
 267 {
 268   u32_t acc;
 269   struct pbuf *q;
 270   u8_t swapped;
 271
 272   acc = 0;
 273   swapped = 0;
 274   /* iterate through all pbuf in chain */
 275   for(q = p; q != NULL; q = q->next) {
 276     LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
 277       (void *)q, (void *)q->next));
 278     acc += LWIP_CHKSUM(q->payload, q->len);
 279     /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
 280     while ((acc >> 16) != 0) {
 281       acc = (acc & 0xffffUL) + (acc >> 16);
 282     }
 283     if (q->len % 2 != 0) {
 284       swapped = 1 - swapped;
 285       acc = ((acc & 0xff) << 8) | ((acc & 0xff00UL) >> 8);
 286     }
 287     /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
 288   }
 289
 290   if (swapped) {
 291     acc = ((acc & 0xff) << 8) | ((acc & 0xff00UL) >> 8);
 292   }
 293   acc += (src->addr & 0xffffUL);
 294   acc += ((src->addr >> 16) & 0xffffUL);
 295   acc += (dest->addr & 0xffffUL);
 296   acc += ((dest->addr >> 16) & 0xffffUL);
 297   acc += (u32_t)htons((u16_t)proto);
 298   acc += (u32_t)htons(proto_len);
 299
 300   while ((acc >> 16) != 0) {
 301     acc = (acc & 0xffffUL) + (acc >> 16);
 302   }
 303   LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
 304   return (u16_t)~(acc & 0xffffUL);
 305 }
 306
 307 /* inet_chksum_pseudo:
 308  *
 309  * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
 310  * IP addresses are expected to be in network byte order.
 311  *
 312  * @param p chain of pbufs over that a checksum should be calculated (ip data part)
 313  * @param src source ip address (used for checksum of pseudo header)
 314  * @param dst destination ip address (used for checksum of pseudo header)
 315  * @param proto ip protocol (used for checksum of pseudo header)
 316  * @param proto_len length of the ip data part (used for checksum of pseudo header)
 317  * @return checksum (as u16_t) to be saved directly in the protocol header
 318  */
 319 u16_t
 320 inet_chksum_pseudo_partial(struct pbuf *p,
 321        struct ip_addr *src, struct ip_addr *dest,
 322        u8_t proto, u16_t proto_len, u16_t chksum_len)
 323 {
 324   u32_t acc;
 325   struct pbuf *q;
 326   u8_t swapped;
 327   u16_t chklen;
 328
 329   acc = 0;
 330   swapped = 0;
 331   /* iterate through all pbuf in chain */
 332   for(q = p; (q != NULL) && (chksum_len > 0); q = q->next) {
 333     LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
 334       (void *)q, (void *)q->next));
 335     chklen = q->len;
 336     if (chklen > chksum_len) {
 337       chklen = chksum_len;
 338     }
 339     acc += LWIP_CHKSUM(q->payload, chklen);
 340     chksum_len -= chklen;
 341     LWIP_ASSERT("delete me", chksum_len < 0x7fff);
 342     /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
 343     while ((acc >> 16) != 0) {
 344       acc = (acc & 0xffffUL) + (acc >> 16);
 345     }
 346     if (q->len % 2 != 0) {
 347       swapped = 1 - swapped;
 348       acc = ((acc & 0xff) << 8) | ((acc & 0xff00UL) >> 8);
 349     }
 350     /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
 351   }
 352
 353   if (swapped) {
 354     acc = ((acc & 0xff) << 8) | ((acc & 0xff00UL) >> 8);
 355   }
 356   acc += (src->addr & 0xffffUL);
 357   acc += ((src->addr >> 16) & 0xffffUL);
 358   acc += (dest->addr & 0xffffUL);
 359   acc += ((dest->addr >> 16) & 0xffffUL);
 360   acc += (u32_t)htons((u16_t)proto);
 361   acc += (u32_t)htons(proto_len);
 362
 363   while ((acc >> 16) != 0) {
 364     acc = (acc & 0xffffUL) + (acc >> 16);
 365   }
 366   LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
 367   return (u16_t)~(acc & 0xffffUL);
 368 }
 369
 370 /* inet_chksum:
 371  *
 372  * Calculates the Internet checksum over a portion of memory. Used primarily for IP
 373  * and ICMP.
 374  *
 375  * @param dataptr start of the buffer to calculate the checksum (no alignment needed)
 376  * @param len length of the buffer to calculate the checksum
 377  * @return checksum (as u16_t) to be saved directly in the protocol header
 378  */
 379
 380 u16_t
 381 inet_chksum(void *dataptr, u16_t len)
 382 {
 383   u32_t acc;
 384
 385   acc = LWIP_CHKSUM(dataptr, len);
 386   while ((acc >> 16) != 0) {
 387     acc = (acc & 0xffff) + (acc >> 16);
 388   }
 389   return (u16_t)~(acc & 0xffff);
 390 }
 391
 392 /**
 393  * Calculate a checksum over a chain of pbufs (without pseudo-header, much like
 394  * inet_chksum only pbufs are used).
 395  *
 396  * @param p pbuf chain over that the checksum should be calculated
 397  * @return checksum (as u16_t) to be saved directly in the protocol header
 398  */
 399 u16_t
 400 inet_chksum_pbuf(struct pbuf *p)
 401 {
 402   u32_t acc;
 403   struct pbuf *q;
 404   u8_t swapped;
 405
 406   acc = 0;
 407   swapped = 0;
 408   for(q = p; q != NULL; q = q->next) {
 409     acc += LWIP_CHKSUM(q->payload, q->len);
 410     while ((acc >> 16) != 0) {
 411       acc = (acc & 0xffffUL) + (acc >> 16);
 412     }
 413     if (q->len % 2 != 0) {
 414       swapped = 1 - swapped;
 415       acc = (acc & 0x00ffUL << 8) | (acc & 0xff00UL >> 8);
 416     }
 417   }
 418
 419   if (swapped) {
 420     acc = ((acc & 0x00ffUL) << 8) | ((acc & 0xff00UL) >> 8);
 421   }
 422   return (u16_t)~(acc & 0xffffUL);
 423 }