ReactOS  0.4.14-dev-384-g5b37caa
inet_chksum.c
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1 
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/def.h"
43 
44 #include <stddef.h>
45 #include <string.h>
46 
47 /* These are some reference implementations of the checksum algorithm, with the
48  * aim of being simple, correct and fully portable. Checksumming is the
49  * first thing you would want to optimize for your platform. If you create
50  * your own version, link it in and in your cc.h put:
51  *
52  * #define LWIP_CHKSUM <your_checksum_routine>
53  *
54  * Or you can select from the implementations below by defining
55  * LWIP_CHKSUM_ALGORITHM to 1, 2 or 3.
56  */
57 
58 #ifndef LWIP_CHKSUM
59 # define LWIP_CHKSUM lwip_standard_chksum
60 # ifndef LWIP_CHKSUM_ALGORITHM
61 # define LWIP_CHKSUM_ALGORITHM 2
62 # endif
63 #endif
64 /* If none set: */
65 #ifndef LWIP_CHKSUM_ALGORITHM
66 # define LWIP_CHKSUM_ALGORITHM 0
67 #endif
68 
69 #if (LWIP_CHKSUM_ALGORITHM == 1) /* Version #1 */
70 
80 static u16_t
82 {
83  u32_t acc;
84  u16_t src;
85  u8_t *octetptr;
86 
87  acc = 0;
88  /* dataptr may be at odd or even addresses */
89  octetptr = (u8_t*)dataptr;
90  while (len > 1) {
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  /* accumulate remaining octet */
103  src = (*octetptr) << 8;
104  acc += src;
105  }
106  /* add deferred carry bits */
107  acc = (acc >> 16) + (acc & 0x0000ffffUL);
108  if ((acc & 0xffff0000UL) != 0) {
109  acc = (acc >> 16) + (acc & 0x0000ffffUL);
110  }
111  /* This maybe a little confusing: reorder sum using htons()
112  instead of ntohs() since it has a little less call overhead.
113  The caller must invert bits for Internet sum ! */
114  return htons((u16_t)acc);
115 }
116 #endif
117 
118 #if (LWIP_CHKSUM_ALGORITHM == 2) /* Alternative version #2 */
119 /*
120  * Curt McDowell
121  * Broadcom Corp.
122  * csm@broadcom.com
123  *
124  * IP checksum two bytes at a time with support for
125  * unaligned buffer.
126  * Works for len up to and including 0x20000.
127  * by Curt McDowell, Broadcom Corp. 12/08/2005
128  *
129  * @param dataptr points to start of data to be summed at any boundary
130  * @param len length of data to be summed
131  * @return host order (!) lwip checksum (non-inverted Internet sum)
132  */
133 
134 static u16_t
136 {
137  u8_t *pb = (u8_t *)dataptr;
138  u16_t *ps, t = 0;
139  u32_t sum = 0;
140  int odd = ((mem_ptr_t)pb & 1);
141 
142  /* Get aligned to u16_t */
143  if (odd && len > 0) {
144  ((u8_t *)&t)[1] = *pb++;
145  len--;
146  }
147 
148  /* Add the bulk of the data */
149  ps = (u16_t *)(void *)pb;
150  while (len > 1) {
151  sum += *ps++;
152  len -= 2;
153  }
154 
155  /* Consume left-over byte, if any */
156  if (len > 0) {
157  ((u8_t *)&t)[0] = *(u8_t *)ps;
158  }
159 
160  /* Add end bytes */
161  sum += t;
162 
163  /* Fold 32-bit sum to 16 bits
164  calling this twice is propably faster than if statements... */
165  sum = FOLD_U32T(sum);
166  sum = FOLD_U32T(sum);
167 
168  /* Swap if alignment was odd */
169  if (odd) {
171  }
172 
173  return (u16_t)sum;
174 }
175 #endif
176 
177 #if (LWIP_CHKSUM_ALGORITHM == 3) /* Alternative version #3 */
178 
190 static u16_t
191 lwip_standard_chksum(void *dataptr, int len)
192 {
193  u8_t *pb = (u8_t *)dataptr;
194  u16_t *ps, t = 0;
195  u32_t *pl;
196  u32_t sum = 0, tmp;
197  /* starts at odd byte address? */
198  int odd = ((mem_ptr_t)pb & 1);
199 
200  if (odd && len > 0) {
201  ((u8_t *)&t)[1] = *pb++;
202  len--;
203  }
204 
205  ps = (u16_t *)pb;
206 
207  if (((mem_ptr_t)ps & 3) && len > 1) {
208  sum += *ps++;
209  len -= 2;
210  }
211 
212  pl = (u32_t *)ps;
213 
214  while (len > 7) {
215  tmp = sum + *pl++; /* ping */
216  if (tmp < sum) {
217  tmp++; /* add back carry */
218  }
219 
220  sum = tmp + *pl++; /* pong */
221  if (sum < tmp) {
222  sum++; /* add back carry */
223  }
224 
225  len -= 8;
226  }
227 
228  /* make room in upper bits */
229  sum = FOLD_U32T(sum);
230 
231  ps = (u16_t *)pl;
232 
233  /* 16-bit aligned word remaining? */
234  while (len > 1) {
235  sum += *ps++;
236  len -= 2;
237  }
238 
239  /* dangling tail byte remaining? */
240  if (len > 0) { /* include odd byte */
241  ((u8_t *)&t)[0] = *(u8_t *)ps;
242  }
243 
244  sum += t; /* add end bytes */
245 
246  /* Fold 32-bit sum to 16 bits
247  calling this twice is propably faster than if statements... */
248  sum = FOLD_U32T(sum);
249  sum = FOLD_U32T(sum);
250 
251  if (odd) {
253  }
254 
255  return (u16_t)sum;
256 }
257 #endif
258 
259 /* inet_chksum_pseudo:
260  *
261  * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
262  * IP addresses are expected to be in network byte order.
263  *
264  * @param p chain of pbufs over that a checksum should be calculated (ip data part)
265  * @param src source ip address (used for checksum of pseudo header)
266  * @param dst destination ip address (used for checksum of pseudo header)
267  * @param proto ip protocol (used for checksum of pseudo header)
268  * @param proto_len length of the ip data part (used for checksum of pseudo header)
269  * @return checksum (as u16_t) to be saved directly in the protocol header
270  */
271 u16_t
274  u8_t proto, u16_t proto_len)
275 {
276  u32_t acc;
277  u32_t addr;
278  struct pbuf *q;
279  u8_t swapped;
280 
281  acc = 0;
282  swapped = 0;
283  /* iterate through all pbuf in chain */
284  for(q = p; q != NULL; q = q->next) {
285  LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
286  (void *)q, (void *)q->next));
287  acc += LWIP_CHKSUM(q->payload, q->len);
288  /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
289  /* just executing this next line is probably faster that the if statement needed
290  to check whether we really need to execute it, and does no harm */
291  acc = FOLD_U32T(acc);
292  if (q->len % 2 != 0) {
293  swapped = 1 - swapped;
294  acc = SWAP_BYTES_IN_WORD(acc);
295  }
296  /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
297  }
298 
299  if (swapped) {
300  acc = SWAP_BYTES_IN_WORD(acc);
301  }
303  acc += (addr & 0xffffUL);
304  acc += ((addr >> 16) & 0xffffUL);
306  acc += (addr & 0xffffUL);
307  acc += ((addr >> 16) & 0xffffUL);
308  acc += (u32_t)htons((u16_t)proto);
309  acc += (u32_t)htons(proto_len);
310 
311  /* Fold 32-bit sum to 16 bits
312  calling this twice is propably faster than if statements... */
313  acc = FOLD_U32T(acc);
314  acc = FOLD_U32T(acc);
315  LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
316  return (u16_t)~(acc & 0xffffUL);
317 }
318 
319 /* inet_chksum_pseudo:
320  *
321  * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
322  * IP addresses are expected to be in network byte order.
323  *
324  * @param p chain of pbufs over that a checksum should be calculated (ip data part)
325  * @param src source ip address (used for checksum of pseudo header)
326  * @param dst destination ip address (used for checksum of pseudo header)
327  * @param proto ip protocol (used for checksum of pseudo header)
328  * @param proto_len length of the ip data part (used for checksum of pseudo header)
329  * @return checksum (as u16_t) to be saved directly in the protocol header
330  */
331 u16_t
334  u8_t proto, u16_t proto_len, u16_t chksum_len)
335 {
336  u32_t acc;
337  u32_t addr;
338  struct pbuf *q;
339  u8_t swapped;
340  u16_t chklen;
341 
342  acc = 0;
343  swapped = 0;
344  /* iterate through all pbuf in chain */
345  for(q = p; (q != NULL) && (chksum_len > 0); q = q->next) {
346  LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
347  (void *)q, (void *)q->next));
348  chklen = q->len;
349  if (chklen > chksum_len) {
350  chklen = chksum_len;
351  }
352  acc += LWIP_CHKSUM(q->payload, chklen);
353  chksum_len -= chklen;
354  LWIP_ASSERT("delete me", chksum_len < 0x7fff);
355  /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
356  /* fold the upper bit down */
357  acc = FOLD_U32T(acc);
358  if (q->len % 2 != 0) {
359  swapped = 1 - swapped;
360  acc = SWAP_BYTES_IN_WORD(acc);
361  }
362  /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
363  }
364 
365  if (swapped) {
366  acc = SWAP_BYTES_IN_WORD(acc);
367  }
369  acc += (addr & 0xffffUL);
370  acc += ((addr >> 16) & 0xffffUL);
372  acc += (addr & 0xffffUL);
373  acc += ((addr >> 16) & 0xffffUL);
374  acc += (u32_t)htons((u16_t)proto);
375  acc += (u32_t)htons(proto_len);
376 
377  /* Fold 32-bit sum to 16 bits
378  calling this twice is propably faster than if statements... */
379  acc = FOLD_U32T(acc);
380  acc = FOLD_U32T(acc);
381  LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
382  return (u16_t)~(acc & 0xffffUL);
383 }
384 
385 /* inet_chksum:
386  *
387  * Calculates the Internet checksum over a portion of memory. Used primarily for IP
388  * and ICMP.
389  *
390  * @param dataptr start of the buffer to calculate the checksum (no alignment needed)
391  * @param len length of the buffer to calculate the checksum
392  * @return checksum (as u16_t) to be saved directly in the protocol header
393  */
394 
395 u16_t
397 {
398  return ~LWIP_CHKSUM(dataptr, len);
399 }
400 
408 u16_t
410 {
411  u32_t acc;
412  struct pbuf *q;
413  u8_t swapped;
414 
415  acc = 0;
416  swapped = 0;
417  for(q = p; q != NULL; q = q->next) {
418  acc += LWIP_CHKSUM(q->payload, q->len);
419  acc = FOLD_U32T(acc);
420  if (q->len % 2 != 0) {
421  swapped = 1 - swapped;
422  acc = SWAP_BYTES_IN_WORD(acc);
423  }
424  }
425 
426  if (swapped) {
427  acc = SWAP_BYTES_IN_WORD(acc);
428  }
429  return (u16_t)~(acc & 0xffffUL);
430 }
431 
432 /* These are some implementations for LWIP_CHKSUM_COPY, which copies data
433  * like MEMCPY but generates a checksum at the same time. Since this is a
434  * performance-sensitive function, you might want to create your own version
435  * in assembly targeted at your hardware by defining it in lwipopts.h:
436  * #define LWIP_CHKSUM_COPY(dst, src, len) your_chksum_copy(dst, src, len)
437  */
438 
439 #if (LWIP_CHKSUM_COPY_ALGORITHM == 1) /* Version #1 */
440 
444 u16_t
445 lwip_chksum_copy(void *dst, const void *src, u16_t len)
446 {
447  MEMCPY(dst, src, len);
448  return LWIP_CHKSUM(dst, len);
449 }
450 #endif /* (LWIP_CHKSUM_COPY_ALGORITHM == 1) */
#define X32_F
Definition: cc.h:41
GLdouble GLdouble t
Definition: gl.h:2047
u16_t inet_chksum_pseudo(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, u8_t proto, u16_t proto_len)
Definition: inet_chksum.c:272
Definition: unary.h:11
typedefPACK_STRUCT_END struct ip_addr ip_addr_t
Definition: ip_addr.h:64
static u16_t lwip_standard_chksum(void *dataptr, int len)
Definition: inet_chksum.c:135
#define LWIP_ASSERT(message, assertion)
Definition: debug.h:66
#define INET_DEBUG
Definition: opt.h:1954
smooth NULL
Definition: ftsmooth.c:416
u16_t inet_chksum_pbuf(struct pbuf *p)
Definition: inet_chksum.c:409
#define LWIP_DEBUGF(debug, message)
Definition: debug.h:95
u16_t inet_chksum(void *dataptr, u16_t len)
Definition: inet_chksum.c:396
static int sum(int x_, int y_)
Definition: ptr2_test.cpp:35
Definition: pbuf.h:79
unsigned long u32_t
Definition: cc.h:25
#define MEMCPY(DST, SRC, BYTES)
Definition: macros.h:231
#define SWAP_BYTES_IN_WORD(w)
Definition: inet_chksum.h:47
#define FOLD_U32T(u)
Definition: inet_chksum.h:53
GLdouble GLdouble GLdouble GLdouble q
Definition: gl.h:2063
GLenum const GLvoid * addr
Definition: glext.h:9621
GLenum GLsizei len
Definition: glext.h:6722
GLenum src
Definition: glext.h:6340
ULONG_PTR mem_ptr_t
Definition: cc.h:33
GLenum GLenum dst
Definition: glext.h:6340
unsigned char u8_t
Definition: cc.h:23
#define LWIP_CHKSUM
Definition: inet_chksum.c:59
u16_t inet_chksum_pseudo_partial(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, u8_t proto, u16_t proto_len, u16_t chksum_len)
Definition: inet_chksum.c:332
int const JOCTET * dataptr
Definition: jpeglib.h:1027
static char * dest
Definition: rtl.c:135
unsigned short u16_t
Definition: cc.h:24
GLfloat GLfloat p
Definition: glext.h:8902
#define htons(x)
Definition: module.h:213
#define UL
Definition: tui.h:83
#define ip4_addr_get_u32(src_ipaddr)
Definition: ip_addr.h:181