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
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
/* ntp.c - Network Timxe Protocol module for sendip
* Author: Mike Ricketts <mike@earth.li>
* ChangeLog since 2.1 release:
*/
#include <stdlib.h>
#include <sys/types.h>
#include <math.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include "sendip_module.h"
#include "ntp.h"
/* Character that identifies our options
*/
const char opt_char='n';
u_int32_t make_fixed_point(double n, bool issigned, int totbits, int intbits) {
u_int32_t intpart;
u_int32_t fracpart;
u_int32_t result;
bool signbit;
double intpartd, fracpartd;
int fracbits;
if(issigned) totbits--;
fracbits=totbits-intbits;
if(issigned && n<0) {
signbit=TRUE;
} else {
signbit=FALSE;
} /* else, signbit is unused */
n=fabs(n);
/*
fracpartd=floor(ldexp(modf(n,&intpartd),ldexp(2.0,fracbits)));
*/
fracpartd=floor(ldexp(modf(n,&intpartd),32));
intpart=(u_int32_t)intpartd;
fracpart=(u_int32_t)fracpartd;
if(issigned&&signbit) {
result=1<<totbits;
} else {
result=0;
}
if(intbits!=0) {
intpart&=(1<<intbits)-1;
intpart<<=(totbits-intbits);
result|=intpart;
}
if(intbits!=totbits) {
if(fracbits!=32) {
fracpart&=((1<<fracbits)-1)<<intbits;
fracpart>>=intbits;
}
result|=fracpart;
}
return htonl(result);
}
bool make_ts(ntp_ts *dest, char *src) {
char *intpart, *fracpart;
intpart=src;
fracpart=strchr(intpart,'.');
if(*intpart) {
dest->intpart=(u_int32_t)strtoul(intpart,&fracpart,0);
} else {
dest->intpart=0;
}
fracpart++; // skip the .
if(fracpart && *fracpart) {
double d;
d = strtod(fracpart-1,(char **)NULL);
dest->fracpart=make_fixed_point(d,FALSE,32,0);
}
return TRUE;
}
sendip_data *initialize(void) {
sendip_data *ret = malloc(sizeof(sendip_data));
ntp_header *ntp = malloc(sizeof(ntp_header));
memset(ntp,0,sizeof(ntp_header));
ret->alloc_len = sizeof(ntp_header);
ret->data = (void *)ntp;
ret->modified=0;
return ret;
}
bool do_opt(char *opt, char *arg, sendip_data *pack) {
ntp_header *ntp = (ntp_header *)pack->data;
switch(opt[1]) {
case 'l': /* Leap Indicator (2 bits) */
ntp->leap=(u_int8_t)strtoul(arg,(char **)NULL,0)&3;
pack->modified|=NTP_MOD_LEAP;
break;
case 's': /* Status (6 bits, values 0-4 defined */
ntp->status=(u_int8_t)strtoul(arg,(char **)NULL,0)&0x3F;
pack->modified|=NTP_MOD_STATUS;
break;
case 't': /* Type (8 bits, values 0-4 defined */
ntp->type=(u_int8_t)strtoul(arg,(char **)NULL,0)&0xFF;
pack->modified|=NTP_MOD_TYPE;
break;
case 'p': /* precision (16 bits, range +32 to -32) */
ntp->precision=htons((int8_t)strtol(arg,(char **)NULL,0));
pack->modified|=NTP_MOD_PRECISION;
break;
case 'e': /* esitmated error (32 bits, fixed point between bits 15/16) */
ntp->error=make_fixed_point(strtod(arg,(char **)NULL),FALSE,32,16);
pack->modified|=NTP_MOD_ERROR;
break;
case 'd': /* estimated drift rate (32 bits, signed fixed point left of
high order bit) */
ntp->drift=make_fixed_point(strtod(arg,(char **)NULL),TRUE,32,0);
pack->modified|=NTP_MOD_DRIFT;
break;
case 'r': /* reference clock id (32 bits or a 4 byte string). Can be:
If type==1: "WWVB", "GOES", "WWV\0"
If type==2: IP address
Else: must be zero
*/
if('0'<=*arg&&*arg<='9') {
/* either a number or an IP */
if((ntp->reference.ipaddr=inet_addr(arg))==-1) {
/* Not a valid IP, or really want 255.255.255.255 */
if(strcmp(arg,"255.255.255.255")) {
ntp->reference.ipaddr=htonl(strtol(arg,(char **)NULL,0));
}
}
} else {
/* Hopefully a 4 byte or less string */
ntp->reference.ipaddr = 0;
if(strlen(arg)<=4) {
memcpy(ntp->reference.id,arg,strlen(arg));
} else {
usage_error("NTP reference clock ID must be IP addr, 32 bit integer, or 4 byte string\n");
return FALSE;
}
}
pack->modified|=NTP_MOD_REF;
break;
case 'f': /* reference timestamp (64 bits) */
if(make_ts(&(ntp->reference_ts),arg)) {
pack->modified|=NTP_MOD_REFERENCE;
} else {
usage_error("Couldn't parse NTP reference timestamp\n");
return FALSE;
}
break;
case 'o': /* originate timestamp (64 bits) */
if(make_ts(&(ntp->originate_ts),arg)) {
pack->modified|=NTP_MOD_ORIGINATE;
} else {
usage_error("Couldn't parse NTP originate timestamp\n");
return FALSE;
}
break;
case 'a': /* receive timestamp (64 bits) */
if(make_ts(&(ntp->receive_ts),arg)) {
pack->modified|=NTP_MOD_RECEIVE;
} else {
usage_error("Couldn't parse NTP receive timestamp\n");
return FALSE;
}
break;
case 'x': /* transmit timestamp (64 bits) */
if(make_ts(&(ntp->transmit_ts),arg)) {
pack->modified|=NTP_MOD_TRANSMIT;
} else {
usage_error("Couldn't parse NTP transmit timestamp\n");
return FALSE;
}
break;
}
return TRUE;
}
bool finalize(char *hdrs, sendip_data *headers[], sendip_data *data,
sendip_data *pack) {
if(hdrs[strlen(hdrs)-1] != 'u') {
usage_error("Warning: NTP should be contained in a UDP packet\n");
}
return TRUE;
}
int num_opts() {
return sizeof(ntp_opts)/sizeof(sendip_option);
}
sendip_option *get_opts() {
return ntp_opts;
}
char get_optchar() {
return opt_char;
}
|
