1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
|
/**************************************************************************
MISC Support Routines
**************************************************************************/
#include "etherboot.h"
#include "console.h"
/**************************************************************************
IPCHKSUM - Checksum IP Header
**************************************************************************/
uint16_t ipchksum(const void *data, unsigned long length)
{
unsigned long sum;
unsigned long i;
const uint8_t *ptr;
/* In the most straight forward way possible,
* compute an ip style checksum.
*/
sum = 0;
ptr = data;
for(i = 0; i < length; i++) {
unsigned long value;
value = ptr[i];
if (i & 1) {
value <<= 8;
}
/* Add the new value */
sum += value;
/* Wrap around the carry */
if (sum > 0xFFFF) {
sum = (sum + (sum >> 16)) & 0xFFFF;
}
}
return (~cpu_to_le16(sum)) & 0xFFFF;
}
uint16_t add_ipchksums(unsigned long offset, uint16_t sum, uint16_t new)
{
unsigned long checksum;
sum = ~sum & 0xFFFF;
new = ~new & 0xFFFF;
if (offset & 1) {
/* byte swap the sum if it came from an odd offset
* since the computation is endian independant this
* works.
*/
new = bswap_16(new);
}
checksum = sum + new;
if (checksum > 0xFFFF) {
checksum -= 0xFFFF;
}
return (~checksum) & 0xFFFF;
}
/**************************************************************************
RANDOM - compute a random number between 0 and 2147483647L or 2147483562?
**************************************************************************/
int32_t random(void)
{
static int32_t seed = 0;
int32_t q;
if (!seed) /* Initialize linear congruential generator */
seed = currticks() + *(int32_t *)&arptable[ARP_CLIENT].node
+ ((int16_t *)arptable[ARP_CLIENT].node)[2];
/* simplified version of the LCG given in Bruce Schneier's
"Applied Cryptography" */
q = seed/53668;
if ((seed = 40014*(seed-53668*q) - 12211*q) < 0) seed += 2147483563L;
return seed;
}
/**************************************************************************
POLL INTERRUPTIONS
**************************************************************************/
void poll_interruptions(void)
{
int ch;
if ( ! as_main_program ) return;
/* If an interruption has occured restart etherboot */
if (iskey() && (ch = getchar(), (ch == K_ESC) || (ch == K_EOF) || (ch == K_INTR))) {
int state = (ch != K_INTR)? -1 : -3;
longjmp(restart_etherboot, state);
}
}
/**************************************************************************
SLEEP
**************************************************************************/
void sleep(int secs)
{
unsigned long tmo;
for (tmo = currticks()+secs*TICKS_PER_SEC; currticks() < tmo; ) {
poll_interruptions();
}
}
/**************************************************************************
INTERRUPTIBLE SLEEP
**************************************************************************/
void interruptible_sleep(int secs)
{
printf("<sleep>\n");
return sleep(secs);
}
/**************************************************************************
TWIDDLE
**************************************************************************/
void twiddle(void)
{
#ifdef BAR_PROGRESS
static int count=0;
static const char tiddles[]="-\\|/";
static unsigned long lastticks = 0;
unsigned long ticks;
#endif
if ( ! as_main_program ) return;
#ifdef BAR_PROGRESS
/* Limit the maximum rate at which characters are printed */
ticks = currticks();
if ((lastticks + (TICKS_PER_SEC/18)) > ticks)
return;
lastticks = ticks;
putchar(tiddles[(count++)&3]);
putchar('\b');
#else
putchar('.');
#endif /* BAR_PROGRESS */
}
/**************************************************************************
STRCASECMP (not entirely correct, but this will do for our purposes)
**************************************************************************/
int strcasecmp(const char *a, const char *b)
{
while (*a && *b && (*a & ~0x20) == (*b & ~0x20)) {a++; b++; }
return((*a & ~0x20) - (*b & ~0x20));
}
/**************************************************************************
INET_ATON - Convert an ascii x.x.x.x to binary form
**************************************************************************/
int inet_aton ( const char *cp, struct in_addr *inp ) {
const char *p = cp;
const char *digits_start;
unsigned long ip = 0;
unsigned long val;
int j;
for(j = 0; j <= 3; j++) {
digits_start = p;
val = strtoul(p, ( char ** ) &p, 10);
if ((p == digits_start) || (val > 255)) return 0;
if ( ( j < 3 ) && ( *(p++) != '.' ) ) return 0;
ip = (ip << 8) | val;
}
if ( *p == '\0' ) {
inp->s_addr = htonl(ip);
return 1;
}
return 0;
}
unsigned long strtoul(const char *p, char **endp, int base)
{
unsigned long ret = 0;
if (base != 10) return 0;
while((*p >= '0') && (*p <= '9')) {
ret = ret*10 + (*p - '0');
p++;
}
if (endp)
*endp = ( char * ) p;
return(ret);
}
/*
* Local variables:
* c-basic-offset: 8
* End:
*/
|
