2 * Routines to support checksumming of bytes.
4 * Copyright (C) 1996 Andrew Tridgell
5 * Copyright (C) 1996 Paul Mackerras
6 * Copyright (C) 2004-2007 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 version 3 as
10 * published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, visit the http://fsf.org website.
23 extern int checksum_seed;
24 extern int protocol_version;
26 int csum_length = SHORT_SUM_LENGTH; /* initial value */
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 md5_update(&m, (uchar *)buf, len);
60 SIVAL(seedbuf, 0, checksum_seed);
61 md5_update(&m, seedbuf, 4);
63 md5_result(&m, (uchar *)sum);
74 buf1 = new_array(char, len+4);
77 out_of_memory("get_checksum2");
80 memcpy(buf1, buf, len);
82 SIVAL(buf1,len,checksum_seed);
86 for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK)
87 mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK);
90 * Prior to version 27 an incorrect MD4 checksum was computed
91 * by failing to call mdfour_tail() for block sizes that
92 * are multiples of 64. This is fixed by calling mdfour_update()
93 * even when there are no more bytes.
95 if (len - i > 0 || protocol_version >= 27)
96 mdfour_update(&m, (uchar *)(buf1+i), len-i);
98 mdfour_result(&m, (uchar *)sum);
102 void file_checksum(char *fname, char *sum, OFF_T size)
104 struct map_struct *buf;
110 memset(sum, 0, MAX_DIGEST_LEN);
112 fd = do_open(fname, O_RDONLY, 0);
116 buf = map_file(fd, size, MAX_MAP_SIZE, CSUM_CHUNK);
118 if (protocol_version >= 30) {
121 for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
122 md5_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
126 remainder = (int32)(len - i);
128 md5_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
130 md5_result(&m, (uchar *)sum);
134 for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
135 mdfour_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
139 /* Prior to version 27 an incorrect MD4 checksum was computed
140 * by failing to call mdfour_tail() for block sizes that
141 * are multiples of 64. This is fixed by calling mdfour_update()
142 * even when there are no more bytes. */
143 remainder = (int32)(len - i);
144 if (remainder > 0 || protocol_version >= 27)
145 mdfour_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
147 mdfour_result(&m, (uchar *)sum);
154 static int32 sumresidue;
155 static md_context md;
157 void sum_init(int seed)
161 if (protocol_version >= 30)
172 * Feed data into an MD4 accumulator, md. The results may be
173 * retrieved using sum_end(). md is used for different purposes at
174 * different points during execution.
176 * @todo Perhaps get rid of md and just pass in the address each time.
177 * Very slightly clearer and slower.
179 void sum_update(const char *p, int32 len)
181 if (protocol_version >= 30) {
182 md5_update(&md, (uchar *)p, len);
186 if (len + sumresidue < CSUM_CHUNK) {
187 memcpy(md.buffer + sumresidue, p, len);
193 int32 i = CSUM_CHUNK - sumresidue;
194 memcpy(md.buffer + sumresidue, p, i);
195 mdfour_update(&md, (uchar *)md.buffer, CSUM_CHUNK);
200 while (len >= CSUM_CHUNK) {
201 mdfour_update(&md, (uchar *)p, CSUM_CHUNK);
208 memcpy(md.buffer, p, sumresidue);
211 int sum_end(char *sum)
213 if (protocol_version >= 30) {
214 md5_result(&md, (uchar *)sum);
215 return MD5_DIGEST_LEN;
218 if (sumresidue || protocol_version >= 27)
219 mdfour_update(&md, (uchar *)md.buffer, sumresidue);
221 mdfour_result(&md, (uchar *)sum);
223 return MD4_DIGEST_LEN;