| 1 | /* |
| 2 | * Routines to support checksumming of bytes. |
| 3 | * |
| 4 | * Copyright (C) 1996 Andrew Tridgell |
| 5 | * Copyright (C) 1996 Paul Mackerras |
| 6 | * Copyright (C) 2004, 2005 Wayne Davison |
| 7 | * |
| 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 2 of the License, or |
| 11 | * (at your option) any later version. |
| 12 | * |
| 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. |
| 17 | * |
| 18 | * You should have received a copy of the GNU General Public License along |
| 19 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 20 | * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. |
| 21 | */ |
| 22 | |
| 23 | #include "rsync.h" |
| 24 | |
| 25 | int csum_length=2; /* initial value */ |
| 26 | |
| 27 | #define CSUM_CHUNK 64 |
| 28 | |
| 29 | extern int checksum_seed; |
| 30 | extern int protocol_version; |
| 31 | |
| 32 | /* |
| 33 | a simple 32 bit checksum that can be upadted from either end |
| 34 | (inspired by Mark Adler's Adler-32 checksum) |
| 35 | */ |
| 36 | uint32 get_checksum1(char *buf1, int32 len) |
| 37 | { |
| 38 | int32 i; |
| 39 | uint32 s1, s2; |
| 40 | schar *buf = (schar *)buf1; |
| 41 | |
| 42 | s1 = s2 = 0; |
| 43 | for (i = 0; i < (len-4); i+=4) { |
| 44 | s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] + |
| 45 | 10*CHAR_OFFSET; |
| 46 | s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET); |
| 47 | } |
| 48 | for (; i < len; i++) { |
| 49 | s1 += (buf[i]+CHAR_OFFSET); s2 += s1; |
| 50 | } |
| 51 | return (s1 & 0xffff) + (s2 << 16); |
| 52 | } |
| 53 | |
| 54 | |
| 55 | void get_checksum2(char *buf, int32 len, char *sum) |
| 56 | { |
| 57 | int32 i; |
| 58 | static char *buf1; |
| 59 | static int32 len1; |
| 60 | struct mdfour m; |
| 61 | |
| 62 | if (len > len1) { |
| 63 | if (buf1) |
| 64 | free(buf1); |
| 65 | buf1 = new_array(char, len+4); |
| 66 | len1 = len; |
| 67 | if (!buf1) |
| 68 | out_of_memory("get_checksum2"); |
| 69 | } |
| 70 | |
| 71 | mdfour_begin(&m); |
| 72 | |
| 73 | memcpy(buf1,buf,len); |
| 74 | if (checksum_seed) { |
| 75 | SIVAL(buf1,len,checksum_seed); |
| 76 | len += 4; |
| 77 | } |
| 78 | |
| 79 | for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) { |
| 80 | mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK); |
| 81 | } |
| 82 | /* |
| 83 | * Prior to version 27 an incorrect MD4 checksum was computed |
| 84 | * by failing to call mdfour_tail() for block sizes that |
| 85 | * are multiples of 64. This is fixed by calling mdfour_update() |
| 86 | * even when there are no more bytes. |
| 87 | */ |
| 88 | if (len - i > 0 || protocol_version >= 27) { |
| 89 | mdfour_update(&m, (uchar *)(buf1+i), (len-i)); |
| 90 | } |
| 91 | |
| 92 | mdfour_result(&m, (uchar *)sum); |
| 93 | } |
| 94 | |
| 95 | |
| 96 | void file_checksum(char *fname,char *sum,OFF_T size) |
| 97 | { |
| 98 | OFF_T i; |
| 99 | struct map_struct *buf; |
| 100 | int fd; |
| 101 | OFF_T len = size; |
| 102 | struct mdfour m; |
| 103 | |
| 104 | memset(sum,0,MD4_SUM_LENGTH); |
| 105 | |
| 106 | fd = do_open(fname, O_RDONLY, 0); |
| 107 | if (fd == -1) |
| 108 | return; |
| 109 | |
| 110 | buf = map_file(fd, size, MAX_MAP_SIZE, CSUM_CHUNK); |
| 111 | |
| 112 | mdfour_begin(&m); |
| 113 | |
| 114 | for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) { |
| 115 | mdfour_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK), |
| 116 | CSUM_CHUNK); |
| 117 | } |
| 118 | |
| 119 | /* Prior to version 27 an incorrect MD4 checksum was computed |
| 120 | * by failing to call mdfour_tail() for block sizes that |
| 121 | * are multiples of 64. This is fixed by calling mdfour_update() |
| 122 | * even when there are no more bytes. */ |
| 123 | if (len - i > 0 || protocol_version >= 27) |
| 124 | mdfour_update(&m, (uchar *)map_ptr(buf, i, len-i), len-i); |
| 125 | |
| 126 | mdfour_result(&m, (uchar *)sum); |
| 127 | |
| 128 | close(fd); |
| 129 | unmap_file(buf); |
| 130 | } |
| 131 | |
| 132 | |
| 133 | static int32 sumresidue; |
| 134 | static char sumrbuf[CSUM_CHUNK]; |
| 135 | static struct mdfour md; |
| 136 | |
| 137 | void sum_init(int seed) |
| 138 | { |
| 139 | char s[4]; |
| 140 | mdfour_begin(&md); |
| 141 | sumresidue = 0; |
| 142 | SIVAL(s, 0, seed); |
| 143 | sum_update(s, 4); |
| 144 | } |
| 145 | |
| 146 | /** |
| 147 | * Feed data into an MD4 accumulator, md. The results may be |
| 148 | * retrieved using sum_end(). md is used for different purposes at |
| 149 | * different points during execution. |
| 150 | * |
| 151 | * @todo Perhaps get rid of md and just pass in the address each time. |
| 152 | * Very slightly clearer and slower. |
| 153 | **/ |
| 154 | void sum_update(char *p, int32 len) |
| 155 | { |
| 156 | if (len + sumresidue < CSUM_CHUNK) { |
| 157 | memcpy(sumrbuf + sumresidue, p, len); |
| 158 | sumresidue += len; |
| 159 | return; |
| 160 | } |
| 161 | |
| 162 | if (sumresidue) { |
| 163 | int32 i = CSUM_CHUNK - sumresidue; |
| 164 | memcpy(sumrbuf + sumresidue, p, i); |
| 165 | mdfour_update(&md, (uchar *)sumrbuf, CSUM_CHUNK); |
| 166 | len -= i; |
| 167 | p += i; |
| 168 | } |
| 169 | |
| 170 | while (len >= CSUM_CHUNK) { |
| 171 | mdfour_update(&md, (uchar *)p, CSUM_CHUNK); |
| 172 | len -= CSUM_CHUNK; |
| 173 | p += CSUM_CHUNK; |
| 174 | } |
| 175 | |
| 176 | sumresidue = len; |
| 177 | if (sumresidue) |
| 178 | memcpy(sumrbuf, p, sumresidue); |
| 179 | } |
| 180 | |
| 181 | void sum_end(char *sum) |
| 182 | { |
| 183 | if (sumresidue || protocol_version >= 27) |
| 184 | mdfour_update(&md, (uchar *)sumrbuf, sumresidue); |
| 185 | |
| 186 | mdfour_result(&md, (uchar *)sum); |
| 187 | } |