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Merge commit 'ea01a15a654b9e1c7b37d958f4d1911882ed7781'
[unleashed.git] / kernel / os / ip_cksum.c
blob1fa1c9425bc8ac21c06ef1a1f0cc6af223532be2
1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25 /* Copyright (c) 1990 Mentat Inc. */
26
27 #include <sys/types.h>
28 #include <sys/inttypes.h>
29 #include <sys/systm.h>
30 #include <sys/stream.h>
31 #include <sys/strsun.h>
32 #include <sys/debug.h>
33 #include <sys/ddi.h>
34 #include <sys/vtrace.h>
35 #include <inet/sctp_crc32.h>
36 #include <inet/ip.h>
37
38 #include <sys/multidata.h>
39 #include <sys/multidata_impl.h>
40
41 extern unsigned int ip_ocsum(ushort_t *address, int halfword_count,
42 unsigned int sum);
43
44 /*
45 * Checksum routine for Internet Protocol family headers.
46 * This routine is very heavily used in the network
47 * code and should be modified for each CPU to be as fast as possible.
48 */
49
50 #define mp_len(mp) ((mp)->b_wptr - (mp)->b_rptr)
51
52 /*
53 * Even/Odd checks. Usually it is performed on pointers but may be
54 * used on integers as well. uintptr_t is long enough to hold both
55 * integer and pointer.
56 */
57 #define is_odd(p) (((uintptr_t)(p) & 0x1) != 0)
58 #define is_even(p) (!is_odd(p))
59
60
61 #ifdef ZC_TEST
62 /*
63 * Disable the TCP s/w cksum.
64 * XXX - This is just a hack for testing purpose. Don't use it for
65 * anything else!
66 */
67 int noswcksum = 0;
68 #endif
69 /*
70 * Note: this does not ones-complement the result since it is used
71 * when computing partial checksums.
72 * For nonSTRUIO_IP mblks, assumes mp->b_rptr+offset is 16 bit aligned.
73 * For STRUIO_IP mblks, assumes mp->b_datap->db_struiobase is 16 bit aligned.
74 *
75 * Note: for STRUIO_IP special mblks some data may have been previously
76 * checksumed, this routine will handle additional data prefixed within
77 * an mblk or b_cont (chained) mblk(s). This routine will also handle
78 * suffixed b_cont mblk(s) and data suffixed within an mblk.
79 */
80 unsigned int
81 ip_cksum(mblk_t *mp, int offset, uint_t sum)
82 {
83 ushort_t *w;
84 ssize_t mlen;
85 int pmlen;
86 mblk_t *pmp;
87 dblk_t *dp = mp->b_datap;
88 ushort_t psum = 0;
89
90 #ifdef ZC_TEST
91 if (noswcksum)
92 return (0xffff);
93 #endif
94 ASSERT(dp);
95
96 if (mp->b_cont == NULL) {
97 /*
98 * May be fast-path, only one mblk.
99 */
100 w = (ushort_t *)(mp->b_rptr + offset);
101 if (dp->db_struioflag & STRUIO_IP) {
102 /*
103 * Checksum any data not already done by
104 * the caller and add in any partial checksum.
105 */
106 if ((offset > dp->db_cksumstart) ||
107 mp->b_wptr != (uchar_t *)(mp->b_rptr +
108 dp->db_cksumend)) {
109 /*
110 * Mblk data pointers aren't inclusive
111 * of uio data, so disregard checksum.
112 *
113 * not using all of data in dblk make sure
114 * not use to use the precalculated checksum
115 * in this case.
116 */
117 dp->db_struioflag &= ~STRUIO_IP;
118 goto norm;
119 }
120 ASSERT(mp->b_wptr == (mp->b_rptr + dp->db_cksumend));
121 psum = *(ushort_t *)dp->db_struioun.data;
122 if ((mlen = dp->db_cksumstart - offset) < 0)
123 mlen = 0;
124 if (is_odd(mlen))
125 goto slow;
126 if (mlen && dp->db_cksumstart != dp->db_cksumstuff &&
127 dp->db_cksumend != dp->db_cksumstuff) {
128 /*
129 * There is prefix data to do and some uio
130 * data has already been checksumed and there
131 * is more uio data to do, so do the prefix
132 * data first, then do the remainder of the
133 * uio data.
134 */
135 sum = ip_ocsum(w, mlen >> 1, sum);
136 w = (ushort_t *)(mp->b_rptr +
137 dp->db_cksumstuff);
138 if (is_odd(w)) {
139 pmp = mp;
140 goto slow1;
141 }
142 mlen = dp->db_cksumend - dp->db_cksumstuff;
143 } else if (dp->db_cksumend != dp->db_cksumstuff) {
144 /*
145 * There may be uio data to do, if there is
146 * prefix data to do then add in all of the
147 * uio data (if any) to do, else just do any
148 * uio data.
149 */
150 if (mlen)
151 mlen += dp->db_cksumend
152 - dp->db_cksumstuff;
153 else {
154 w = (ushort_t *)(mp->b_rptr +
155 dp->db_cksumstuff);
156 if (is_odd(w))
157 goto slow;
158 mlen = dp->db_cksumend
159 - dp->db_cksumstuff;
160 }
161 } else if (mlen == 0)
162 return (psum);
163
164 if (is_odd(mlen))
165 goto slow;
166 sum += psum;
167 } else {
168 /*
169 * Checksum all data not already done by the caller.
170 */
171 norm:
172 mlen = mp->b_wptr - (uchar_t *)w;
173 if (is_odd(mlen))
174 goto slow;
175 }
176 ASSERT(is_even(w));
177 ASSERT(is_even(mlen));
178 return (ip_ocsum(w, mlen >> 1, sum));
179 }
180 if (dp->db_struioflag & STRUIO_IP)
181 psum = *(ushort_t *)dp->db_struioun.data;
182 slow:
183 pmp = 0;
184 slow1:
185 mlen = 0;
186 pmlen = 0;
187 for (; ; ) {
188 /*
189 * Each trip around loop adds in word(s) from one mbuf segment
190 * (except for when pmp == mp, then its two partial trips).
191 */
192 w = (ushort_t *)(mp->b_rptr + offset);
193 if (pmp) {
194 /*
195 * This is the second trip around for this mblk.
196 */
197 pmp = 0;
198 mlen = 0;
199 goto douio;
200 } else if (dp->db_struioflag & STRUIO_IP) {
201 /*
202 * Checksum any data not already done by the
203 * caller and add in any partial checksum.
204 */
205 if ((offset > dp->db_cksumstart) ||
206 mp->b_wptr != (uchar_t *)(mp->b_rptr +
207 dp->db_cksumend)) {
208 /*
209 * Mblk data pointers aren't inclusive
210 * of uio data, so disregard checksum.
211 *
212 * not using all of data in dblk make sure
213 * not use to use the precalculated checksum
214 * in this case.
215 */
216 dp->db_struioflag &= ~STRUIO_IP;
217 goto snorm;
218 }
219 ASSERT(mp->b_wptr == (mp->b_rptr + dp->db_cksumend));
220 if ((mlen = dp->db_cksumstart - offset) < 0)
221 mlen = 0;
222 if (mlen && dp->db_cksumstart != dp->db_cksumstuff) {
223 /*
224 * There is prefix data too do and some
225 * uio data has already been checksumed,
226 * so do the prefix data only this trip.
227 */
228 pmp = mp;
229 } else {
230 /*
231 * Add in any partial cksum (if any) and
232 * do the remainder of the uio data.
233 */
234 int odd;
235 douio:
236 odd = is_odd(dp->db_cksumstuff -
237 dp->db_cksumstart);
238 if (pmlen == -1) {
239 /*
240 * Previous mlen was odd, so swap
241 * the partial checksum bytes.
242 */
243 sum += ((psum << 8) & 0xffff)
244 | (psum >> 8);
245 if (odd)
246 pmlen = 0;
247 } else {
248 sum += psum;
249 if (odd)
250 pmlen = -1;
251 }
252 if (dp->db_cksumend != dp->db_cksumstuff) {
253 /*
254 * If prefix data to do and then all
255 * the uio data nees to be checksumed,
256 * else just do any uio data.
257 */
258 if (mlen)
259 mlen += dp->db_cksumend
260 - dp->db_cksumstuff;
261 else {
262 w = (ushort_t *)(mp->b_rptr +
263 dp->db_cksumstuff);
264 mlen = dp->db_cksumend -
265 dp->db_cksumstuff;
266 }
267 }
268 }
269 } else {
270 /*
271 * Checksum all of the mblk data.
272 */
273 snorm:
274 mlen = mp->b_wptr - (uchar_t *)w;
275 }
276
277 mp = mp->b_cont;
278 if (mlen > 0 && pmlen == -1) {
279 /*
280 * There is a byte left from the last
281 * segment; add it into the checksum.
282 * Don't have to worry about a carry-
283 * out here because we make sure that
284 * high part of (32 bit) sum is small
285 * below.
286 */
287 #ifdef _LITTLE_ENDIAN
288 sum += *(uchar_t *)w << 8;
289 #else
290 sum += *(uchar_t *)w;
291 #endif
292 w = (ushort_t *)((char *)w + 1);
293 mlen--;
294 pmlen = 0;
295 }
296 if (mlen > 0) {
297 if (is_even(w)) {
298 sum = ip_ocsum(w, mlen>>1, sum);
299 w += mlen>>1;
300 /*
301 * If we had an odd number of bytes,
302 * then the last byte goes in the high
303 * part of the sum, and we take the
304 * first byte to the low part of the sum
305 * the next time around the loop.
306 */
307 if (is_odd(mlen)) {
308 #ifdef _LITTLE_ENDIAN
309 sum += *(uchar_t *)w;
310 #else
311 sum += *(uchar_t *)w << 8;
312 #endif
313 pmlen = -1;
314 }
315 } else {
316 ushort_t swsum;
317 #ifdef _LITTLE_ENDIAN
318 sum += *(uchar_t *)w;
319 #else
320 sum += *(uchar_t *)w << 8;
321 #endif
322 mlen--;
323 w = (ushort_t *)(1 + (uintptr_t)w);
324
325 /* Do a separate checksum and copy operation */
326 swsum = ip_ocsum(w, mlen>>1, 0);
327 sum += ((swsum << 8) & 0xffff) | (swsum >> 8);
328 w += mlen>>1;
329 /*
330 * If we had an even number of bytes,
331 * then the last byte goes in the low
332 * part of the sum. Otherwise we had an
333 * odd number of bytes and we take the first
334 * byte to the low part of the sum the
335 * next time around the loop.
336 */
337 if (is_odd(mlen)) {
338 #ifdef _LITTLE_ENDIAN
339 sum += *(uchar_t *)w << 8;
340 #else
341 sum += *(uchar_t *)w;
342 #endif
343 }
344 else
345 pmlen = -1;
346 }
347 }
348 /*
349 * Locate the next block with some data.
350 * If there is a word split across a boundary we
351 * will wrap to the top with mlen == -1 and
352 * then add it in shifted appropriately.
353 */
354 offset = 0;
355 if (! pmp) {
356 for (; ; ) {
357 if (mp == 0) {
358 goto done;
359 }
360 if (mp_len(mp))
361 break;
362 mp = mp->b_cont;
363 }
364 dp = mp->b_datap;
365 if (dp->db_struioflag & STRUIO_IP)
366 psum = *(ushort_t *)dp->db_struioun.data;
367 } else
368 mp = pmp;
369 }
370 done:
371 /*
372 * Add together high and low parts of sum
373 * and carry to get cksum.
374 * Have to be careful to not drop the last
375 * carry here.
376 */
377 sum = (sum & 0xFFFF) + (sum >> 16);
378 sum = (sum & 0xFFFF) + (sum >> 16);
379 TRACE_3(TR_FAC_IP, TR_IP_CKSUM_END,
380 "ip_cksum_end:(%S) type %d (%X)", "ip_cksum", 1, sum);
381 return (sum);
382 }
383
384 uint32_t
385 sctp_cksum(mblk_t *mp, int offset)
386 {
387 uint32_t crc32;
388 uchar_t *p = NULL;
389
390 crc32 = 0xFFFFFFFF;
391 p = mp->b_rptr + offset;
392 crc32 = sctp_crc32(crc32, p, mp->b_wptr - p);
393 for (mp = mp->b_cont; mp != NULL; mp = mp->b_cont) {
394 crc32 = sctp_crc32(crc32, mp->b_rptr, MBLKL(mp));
395 }
396
397 /* Complement the result */
398 crc32 = ~crc32;
399
400 return (crc32);
401 }
402
403 /*
404 * Routine to compute Internet checksum (16-bit 1's complement) of a given
405 * Multidata packet descriptor. As in the non-Multidata routine, this doesn't
406 * 1's complement the result, such that it may be used to compute partial
407 * checksums. Since it works on buffer spans rather than mblks, this routine
408 * does not handle existing partial checksum value as in the STRUIO_IP special
409 * mblk case (supporting this is rather trivial, but is perhaps of no use at
410 * the moment unless synchronous streams and delayed checksum calculation are
411 * revived.)
412 *
413 * Note also here that the given Multidata packet descriptor must refer to
414 * a header buffer, i.e. it must have a header fragment. In addition, the
415 * offset must lie within the boundary of the header fragment. For the
416 * outbound tcp (MDT) case, this will not be an issue because the stack
417 * ensures that such conditions are met, and that there is no need whatsoever
418 * to compute partial checksums on an arbitrary offset that is not part of
419 * the header fragment. We may need to revisit this routine to handle all
420 * cases of the inbound (MDR) case, especially when we need to perform partial
421 * checksum calculation due to padded bytes (non-zeroes) in the frame.
422 */
423 uint_t
424 ip_md_cksum(pdesc_t *pd, int offset, uint_t sum)
425 {
426 pdescinfo_t *pdi = &pd->pd_pdi;
427 uchar_t *reg_start, *reg_end;
428 ssize_t mlen, i;
429 ushort_t *w;
430 boolean_t byteleft = B_FALSE;
431
432 ASSERT((pdi->flags & PDESC_HAS_REF) != 0);
433 ASSERT(pdi->hdr_rptr != NULL && pdi->hdr_wptr != NULL);
434 ASSERT(offset <= PDESC_HDRL(pdi));
435
436 for (i = 0; i < pdi->pld_cnt + 1; i++) {
437 if (i == 0) {
438 reg_start = pdi->hdr_rptr;
439 reg_end = pdi->hdr_wptr;
440 } else {
441 reg_start = pdi->pld_ary[i - 1].pld_rptr;
442 reg_end = pdi->pld_ary[i - 1].pld_wptr;
443 offset = 0;
444 }
445
446 w = (ushort_t *)(reg_start + offset);
447 mlen = reg_end - (uchar_t *)w;
448
449 if (mlen > 0 && byteleft) {
450 /*
451 * There is a byte left from the last
452 * segment; add it into the checksum.
453 * Don't have to worry about a carry-
454 * out here because we make sure that
455 * high part of (32 bit) sum is small
456 * below.
457 */
458 #ifdef _LITTLE_ENDIAN
459 sum += *(uchar_t *)w << 8;
460 #else
461 sum += *(uchar_t *)w;
462 #endif
463 w = (ushort_t *)((char *)w + 1);
464 mlen--;
465 byteleft = B_FALSE;
466 }
467
468 if (mlen == 0)
469 continue;
470
471 if (is_even(w)) {
472 sum = ip_ocsum(w, mlen >> 1, sum);
473 w += mlen >> 1;
474 /*
475 * If we had an odd number of bytes,
476 * then the last byte goes in the high
477 * part of the sum, and we take the
478 * first byte to the low part of the sum
479 * the next time around the loop.
480 */
481 if (is_odd(mlen)) {
482 #ifdef _LITTLE_ENDIAN
483 sum += *(uchar_t *)w;
484 #else
485 sum += *(uchar_t *)w << 8;
486 #endif
487 byteleft = B_TRUE;
488 }
489 } else {
490 ushort_t swsum;
491 #ifdef _LITTLE_ENDIAN
492 sum += *(uchar_t *)w;
493 #else
494 sum += *(uchar_t *)w << 8;
495 #endif
496 mlen--;
497 w = (ushort_t *)(1 + (uintptr_t)w);
498
499 /* Do a separate checksum and copy operation */
500 swsum = ip_ocsum(w, mlen >> 1, 0);
501 sum += ((swsum << 8) & 0xffff) | (swsum >> 8);
502 w += mlen >> 1;
503 /*
504 * If we had an even number of bytes,
505 * then the last byte goes in the low
506 * part of the sum. Otherwise we had an
507 * odd number of bytes and we take the first
508 * byte to the low part of the sum the
509 * next time around the loop.
510 */
511 if (is_odd(mlen)) {
512 #ifdef _LITTLE_ENDIAN
513 sum += *(uchar_t *)w << 8;
514 #else
515 sum += *(uchar_t *)w;
516 #endif
517 } else {
518 byteleft = B_TRUE;
519 }
520 }
521 }
522
523 /*
524 * Add together high and low parts of sum and carry to get cksum.
525 * Have to be careful to not drop the last carry here.
526 */
527 sum = (sum & 0xffff) + (sum >> 16);
528 sum = (sum & 0xffff) + (sum >> 16);
529
530 return (sum);
531 }
532
533 /* Return the IP checksum for the IP header at "iph". */
534 uint16_t
535 ip_csum_hdr(ipha_t *ipha)
536 {
537 uint16_t *uph;
538 uint32_t sum;
539 int opt_len;
540
541 opt_len = (ipha->ipha_version_and_hdr_length & 0xF) -
542 IP_SIMPLE_HDR_LENGTH_IN_WORDS;
543 uph = (uint16_t *)ipha;
544 sum = uph[0] + uph[1] + uph[2] + uph[3] + uph[4] +
545 uph[5] + uph[6] + uph[7] + uph[8] + uph[9];
546 if (opt_len > 0) {
547 do {
548 sum += uph[10];
549 sum += uph[11];
550 uph += 2;
551 } while (--opt_len);
552 }
553 sum = (sum & 0xFFFF) + (sum >> 16);
554 sum = ~(sum + (sum >> 16)) & 0xFFFF;
555 if (sum == 0xffff)
556 sum = 0;
557 return ((uint16_t)sum);
558 }
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