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- /*
- * Routines to support checksumming of bytes.
- *
- * Copyright (C) 1996 Andrew Tridgell
- * Copyright (C) 1996 Paul Mackerras
- * Copyright (C) 2004-2009 Wayne Davison
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, visit the http://fsf.org website.
- */
- #include "rsync.h"
- extern int checksum_seed;
- extern int protocol_version;
- /*
- a simple 32 bit checksum that can be upadted from either end
- (inspired by Mark Adler's Adler-32 checksum)
- */
- uint32 get_checksum1(char *buf1, int32 len)
- {
- int32 i;
- uint32 s1, s2;
- schar *buf = (schar *)buf1;
- s1 = s2 = 0;
- for (i = 0; i < (len-4); i+=4) {
- s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] +
- 10*CHAR_OFFSET;
- s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET);
- }
- for (; i < len; i++) {
- s1 += (buf[i]+CHAR_OFFSET); s2 += s1;
- }
- return (s1 & 0xffff) + (s2 << 16);
- }
- void get_checksum2(char *buf, int32 len, char *sum)
- {
- md_context m;
- if (protocol_version >= 30) {
- uchar seedbuf[4];
- md5_begin(&m);
- md5_update(&m, (uchar *)buf, len);
- if (checksum_seed) {
- SIVALu(seedbuf, 0, checksum_seed);
- md5_update(&m, seedbuf, 4);
- }
- md5_result(&m, (uchar *)sum);
- } else {
- int32 i;
- static char *buf1;
- static int32 len1;
- mdfour_begin(&m);
- if (len > len1) {
- if (buf1)
- free(buf1);
- buf1 = new_array(char, len+4);
- len1 = len;
- if (!buf1)
- out_of_memory("get_checksum2");
- }
- memcpy(buf1, buf, len);
- if (checksum_seed) {
- SIVAL(buf1,len,checksum_seed);
- len += 4;
- }
- for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK)
- mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK);
- /*
- * Prior to version 27 an incorrect MD4 checksum was computed
- * by failing to call mdfour_tail() for block sizes that
- * are multiples of 64. This is fixed by calling mdfour_update()
- * even when there are no more bytes.
- */
- if (len - i > 0 || protocol_version >= 27)
- mdfour_update(&m, (uchar *)(buf1+i), len-i);
- mdfour_result(&m, (uchar *)sum);
- }
- }
- void file_checksum(char *fname, char *sum, OFF_T size)
- {
- struct map_struct *buf;
- OFF_T i, len = size;
- md_context m;
- int32 remainder;
- int fd;
- memset(sum, 0, MAX_DIGEST_LEN);
- fd = do_open(fname, O_RDONLY, 0);
- if (fd == -1)
- return;
- buf = map_file(fd, size, MAX_MAP_SIZE, CSUM_CHUNK);
- if (protocol_version >= 30) {
- md5_begin(&m);
- for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
- md5_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
- CSUM_CHUNK);
- }
- remainder = (int32)(len - i);
- if (remainder > 0)
- md5_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
- md5_result(&m, (uchar *)sum);
- } else {
- mdfour_begin(&m);
- for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
- mdfour_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
- CSUM_CHUNK);
- }
- /* Prior to version 27 an incorrect MD4 checksum was computed
- * by failing to call mdfour_tail() for block sizes that
- * are multiples of 64. This is fixed by calling mdfour_update()
- * even when there are no more bytes. */
- remainder = (int32)(len - i);
- if (remainder > 0 || protocol_version >= 27)
- mdfour_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
- mdfour_result(&m, (uchar *)sum);
- }
- close(fd);
- unmap_file(buf);
- }
- static int32 sumresidue;
- static md_context md;
- void sum_init(int seed)
- {
- char s[4];
- if (protocol_version >= 30)
- md5_begin(&md);
- else {
- mdfour_begin(&md);
- sumresidue = 0;
- SIVAL(s, 0, seed);
- sum_update(s, 4);
- }
- }
- /**
- * Feed data into an MD4 accumulator, md. The results may be
- * retrieved using sum_end(). md is used for different purposes at
- * different points during execution.
- *
- * @todo Perhaps get rid of md and just pass in the address each time.
- * Very slightly clearer and slower.
- **/
- void sum_update(const char *p, int32 len)
- {
- if (protocol_version >= 30) {
- md5_update(&md, (uchar *)p, len);
- return;
- }
- if (len + sumresidue < CSUM_CHUNK) {
- memcpy(md.buffer + sumresidue, p, len);
- sumresidue += len;
- return;
- }
- if (sumresidue) {
- int32 i = CSUM_CHUNK - sumresidue;
- memcpy(md.buffer + sumresidue, p, i);
- mdfour_update(&md, (uchar *)md.buffer, CSUM_CHUNK);
- len -= i;
- p += i;
- }
- while (len >= CSUM_CHUNK) {
- mdfour_update(&md, (uchar *)p, CSUM_CHUNK);
- len -= CSUM_CHUNK;
- p += CSUM_CHUNK;
- }
- sumresidue = len;
- if (sumresidue)
- memcpy(md.buffer, p, sumresidue);
- }
- int sum_end(char *sum)
- {
- if (protocol_version >= 30) {
- md5_result(&md, (uchar *)sum);
- return MD5_DIGEST_LEN;
- }
- if (sumresidue || protocol_version >= 27)
- mdfour_update(&md, (uchar *)md.buffer, sumresidue);
- mdfour_result(&md, (uchar *)sum);
- return MD4_DIGEST_LEN;
- }
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