2 * Routines to support checksumming of bytes.
4 * Copyright (C) 1996 Andrew Tridgell
5 * Copyright (C) 1996 Paul Mackerras
6 * Copyright (C) 2004-2014 Wayne Davison
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 3 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, visit the http://fsf.org website.
24 extern int checksum_seed;
25 extern int protocol_version;
26 extern int proper_seed_order;
29 a simple 32 bit checksum that can be upadted from either end
30 (inspired by Mark Adler's Adler-32 checksum)
32 uint32 get_checksum1(char *buf1, int32 len)
36 schar *buf = (schar *)buf1;
39 for (i = 0; i < (len-4); i+=4) {
40 s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] +
42 s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET);
44 for (; i < len; i++) {
45 s1 += (buf[i]+CHAR_OFFSET); s2 += s1;
47 return (s1 & 0xffff) + (s2 << 16);
51 void get_checksum2(char *buf, int32 len, char *sum)
55 if (protocol_version >= 30) {
58 if (proper_seed_order) {
60 SIVALu(seedbuf, 0, checksum_seed);
61 md5_update(&m, seedbuf, 4);
63 md5_update(&m, (uchar *)buf, len);
65 md5_update(&m, (uchar *)buf, len);
67 SIVALu(seedbuf, 0, checksum_seed);
68 md5_update(&m, seedbuf, 4);
71 md5_result(&m, (uchar *)sum);
82 buf1 = new_array(char, len+4);
85 out_of_memory("get_checksum2");
88 memcpy(buf1, buf, len);
90 SIVAL(buf1,len,checksum_seed);
94 for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK)
95 mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK);
98 * Prior to version 27 an incorrect MD4 checksum was computed
99 * by failing to call mdfour_tail() for block sizes that
100 * are multiples of 64. This is fixed by calling mdfour_update()
101 * even when there are no more bytes.
103 if (len - i > 0 || protocol_version >= 27)
104 mdfour_update(&m, (uchar *)(buf1+i), len-i);
106 mdfour_result(&m, (uchar *)sum);
110 void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
112 struct map_struct *buf;
113 OFF_T i, len = st_p->st_size;
118 memset(sum, 0, MAX_DIGEST_LEN);
120 fd = do_open(fname, O_RDONLY, 0);
124 buf = map_file(fd, len, MAX_MAP_SIZE, CSUM_CHUNK);
126 if (protocol_version >= 30) {
129 for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
130 md5_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
134 remainder = (int32)(len - i);
136 md5_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
138 md5_result(&m, (uchar *)sum);
142 for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
143 mdfour_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
147 /* Prior to version 27 an incorrect MD4 checksum was computed
148 * by failing to call mdfour_tail() for block sizes that
149 * are multiples of 64. This is fixed by calling mdfour_update()
150 * even when there are no more bytes. */
151 remainder = (int32)(len - i);
152 if (remainder > 0 || protocol_version >= 27)
153 mdfour_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
155 mdfour_result(&m, (uchar *)sum);
162 static int32 sumresidue;
163 static md_context md;
165 void sum_init(int seed)
169 if (protocol_version >= 30)
180 * Feed data into an MD4 accumulator, md. The results may be
181 * retrieved using sum_end(). md is used for different purposes at
182 * different points during execution.
184 * @todo Perhaps get rid of md and just pass in the address each time.
185 * Very slightly clearer and slower.
187 void sum_update(const char *p, int32 len)
189 if (protocol_version >= 30) {
190 md5_update(&md, (uchar *)p, len);
194 if (len + sumresidue < CSUM_CHUNK) {
195 memcpy(md.buffer + sumresidue, p, len);
201 int32 i = CSUM_CHUNK - sumresidue;
202 memcpy(md.buffer + sumresidue, p, i);
203 mdfour_update(&md, (uchar *)md.buffer, CSUM_CHUNK);
208 while (len >= CSUM_CHUNK) {
209 mdfour_update(&md, (uchar *)p, CSUM_CHUNK);
216 memcpy(md.buffer, p, sumresidue);
219 int sum_end(char *sum)
221 if (protocol_version >= 30) {
222 md5_result(&md, (uchar *)sum);
223 return MD5_DIGEST_LEN;
226 if (sumresidue || protocol_version >= 27)
227 mdfour_update(&md, (uchar *)md.buffer, sumresidue);
229 mdfour_result(&md, (uchar *)sum);
231 return MD4_DIGEST_LEN;