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
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
|
/* vi: set sw=4 ts=4: */
/*
* options.c -- DHCP server option packet tools
* Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
*
* Licensed under GPLv2, see file LICENSE in this tarball for details.
*/
#include "common.h"
#include "dhcpd.h"
#include "options.h"
/* Supported options are easily added here */
const struct dhcp_option dhcp_options[] = {
/* flags code */
{ OPTION_IP | OPTION_REQ, 0x01 }, /* DHCP_SUBNET */
{ OPTION_S32 , 0x02 }, /* DHCP_TIME_OFFSET */
{ OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03 }, /* DHCP_ROUTER */
{ OPTION_IP | OPTION_LIST , 0x04 }, /* DHCP_TIME_SERVER */
{ OPTION_IP | OPTION_LIST , 0x05 }, /* DHCP_NAME_SERVER */
{ OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06 }, /* DHCP_DNS_SERVER */
{ OPTION_IP | OPTION_LIST , 0x07 }, /* DHCP_LOG_SERVER */
{ OPTION_IP | OPTION_LIST , 0x08 }, /* DHCP_COOKIE_SERVER */
{ OPTION_IP | OPTION_LIST , 0x09 }, /* DHCP_LPR_SERVER */
{ OPTION_STRING | OPTION_REQ, 0x0c }, /* DHCP_HOST_NAME */
{ OPTION_U16 , 0x0d }, /* DHCP_BOOT_SIZE */
{ OPTION_STRING | OPTION_LIST | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME */
{ OPTION_IP , 0x10 }, /* DHCP_SWAP_SERVER */
{ OPTION_STRING , 0x11 }, /* DHCP_ROOT_PATH */
{ OPTION_U8 , 0x17 }, /* DHCP_IP_TTL */
{ OPTION_U16 , 0x1a }, /* DHCP_MTU */
{ OPTION_IP | OPTION_REQ, 0x1c }, /* DHCP_BROADCAST */
{ OPTION_STRING , 0x28 }, /* nisdomain */
{ OPTION_IP | OPTION_LIST , 0x29 }, /* nissrv */
{ OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a }, /* DHCP_NTP_SERVER */
{ OPTION_IP | OPTION_LIST , 0x2c }, /* DHCP_WINS_SERVER */
{ OPTION_IP , 0x32 }, /* DHCP_REQUESTED_IP */
{ OPTION_U32 , 0x33 }, /* DHCP_LEASE_TIME */
{ OPTION_U8 , 0x35 }, /* dhcptype */
{ OPTION_IP , 0x36 }, /* DHCP_SERVER_ID */
{ OPTION_STRING , 0x38 }, /* DHCP_MESSAGE */
{ OPTION_STRING , 0x3C }, /* DHCP_VENDOR */
{ OPTION_STRING , 0x3D }, /* DHCP_CLIENT_ID */
{ OPTION_STRING , 0x42 }, /* tftp */
{ OPTION_STRING , 0x43 }, /* bootfile */
{ OPTION_STRING , 0x4D }, /* userclass */
#if ENABLE_FEATURE_UDHCP_RFC3397
{ OPTION_STR1035 | OPTION_LIST , 0x77 }, /* search */
#endif
{ OPTION_STATIC_ROUTES , 0x79 }, /* DHCP_STATIC_ROUTES */
/* MSIE's "Web Proxy Autodiscovery Protocol" support */
{ OPTION_STRING , 0xfc }, /* wpad */
/* Options below have no match in dhcp_option_strings[],
* are not passed to dhcpc scripts, and cannot be specified
* with "option XXX YYY" syntax in dhcpd config file. */
{ OPTION_U16 , 0x39 }, /* DHCP_MAX_SIZE */
{ 0, 0 } /* zeroed terminating entry */
};
/* Used for converting options from incoming packets to env variables
* for udhcpc stript */
/* Must match dhcp_options[] order */
const char dhcp_option_strings[] ALIGN1 =
"subnet" "\0" /* DHCP_SUBNET */
"timezone" "\0" /* DHCP_TIME_OFFSET */
"router" "\0" /* DHCP_ROUTER */
"timesrv" "\0" /* DHCP_TIME_SERVER */
"namesrv" "\0" /* DHCP_NAME_SERVER */
"dns" "\0" /* DHCP_DNS_SERVER */
"logsrv" "\0" /* DHCP_LOG_SERVER */
"cookiesrv" "\0" /* DHCP_COOKIE_SERVER */
"lprsrv" "\0" /* DHCP_LPR_SERVER */
"hostname" "\0" /* DHCP_HOST_NAME */
"bootsize" "\0" /* DHCP_BOOT_SIZE */
"domain" "\0" /* DHCP_DOMAIN_NAME */
"swapsrv" "\0" /* DHCP_SWAP_SERVER */
"rootpath" "\0" /* DHCP_ROOT_PATH */
"ipttl" "\0" /* DHCP_IP_TTL */
"mtu" "\0" /* DHCP_MTU */
"broadcast" "\0" /* DHCP_BROADCAST */
"nisdomain" "\0" /* */
"nissrv" "\0" /* */
"ntpsrv" "\0" /* DHCP_NTP_SERVER */
"wins" "\0" /* DHCP_WINS_SERVER */
"requestip" "\0" /* DHCP_REQUESTED_IP */
"lease" "\0" /* DHCP_LEASE_TIME */
"dhcptype" "\0" /* */
"serverid" "\0" /* DHCP_SERVER_ID */
"message" "\0" /* DHCP_MESSAGE */
"vendorclass" "\0" /* DHCP_VENDOR */
"clientid" "\0" /* DHCP_CLIENT_ID */
"tftp" "\0"
"bootfile" "\0"
"userclass" "\0"
#if ENABLE_FEATURE_UDHCP_RFC3397
"search" "\0"
#endif
"staticroutes" "\0" /* DHCP_STATIC_ROUTES */
/* MSIE's "Web Proxy Autodiscovery Protocol" support */
"wpad" "\0"
;
/* Lengths of the different option types */
const uint8_t dhcp_option_lengths[] ALIGN1 = {
[OPTION_IP] = 4,
[OPTION_IP_PAIR] = 8,
[OPTION_BOOLEAN] = 1,
[OPTION_STRING] = 1,
#if ENABLE_FEATURE_UDHCP_RFC3397
[OPTION_STR1035] = 1,
#endif
[OPTION_U8] = 1,
[OPTION_U16] = 2,
[OPTION_S16] = 2,
[OPTION_U32] = 4,
[OPTION_S32] = 4,
/* Just like OPTION_STRING, we use minimum length here */
[OPTION_STATIC_ROUTES] = 5,
};
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
static void log_option(const char *pfx, const uint8_t *opt)
{
if (dhcp_verbose >= 2) {
char buf[256 * 2 + 2];
*bin2hex(buf, (void*) (opt + OPT_DATA), opt[OPT_LEN]) = '\0';
bb_info_msg("%s: 0x%02x %s", pfx, opt[OPT_CODE], buf);
}
}
#else
# define log_option(pfx, opt) ((void)0)
#endif
/* get an option with bounds checking (warning, result is not aligned). */
uint8_t* FAST_FUNC get_option(struct dhcp_packet *packet, int code)
{
uint8_t *optionptr;
int len;
int rem;
int overload = 0;
enum {
FILE_FIELD101 = FILE_FIELD * 0x101,
SNAME_FIELD101 = SNAME_FIELD * 0x101,
};
/* option bytes: [code][len][data1][data2]..[dataLEN] */
optionptr = packet->options;
rem = sizeof(packet->options);
while (1) {
if (rem <= 0) {
bb_error_msg("bogus packet, malformed option field");
return NULL;
}
if (optionptr[OPT_CODE] == DHCP_PADDING) {
rem--;
optionptr++;
continue;
}
if (optionptr[OPT_CODE] == DHCP_END) {
if ((overload & FILE_FIELD101) == FILE_FIELD) {
/* can use packet->file, and didn't look at it yet */
overload |= FILE_FIELD101; /* "we looked at it" */
optionptr = packet->file;
rem = sizeof(packet->file);
continue;
}
if ((overload & SNAME_FIELD101) == SNAME_FIELD) {
/* can use packet->sname, and didn't look at it yet */
overload |= SNAME_FIELD101; /* "we looked at it" */
optionptr = packet->sname;
rem = sizeof(packet->sname);
continue;
}
break;
}
len = 2 + optionptr[OPT_LEN];
rem -= len;
if (rem < 0)
continue; /* complain and return NULL */
if (optionptr[OPT_CODE] == code) {
log_option("Option found", optionptr);
return optionptr + OPT_DATA;
}
if (optionptr[OPT_CODE] == DHCP_OPTION_OVERLOAD) {
overload |= optionptr[OPT_DATA];
/* fall through */
}
optionptr += len;
}
/* log3 because udhcpc uses it a lot - very noisy */
log3("Option 0x%02x not found", code);
return NULL;
}
/* return the position of the 'end' option (no bounds checking) */
int FAST_FUNC end_option(uint8_t *optionptr)
{
int i = 0;
while (optionptr[i] != DHCP_END) {
if (optionptr[i] != DHCP_PADDING)
i += optionptr[i + OPT_LEN] + 1;
i++;
}
return i;
}
/* add an option string to the options */
/* option bytes: [code][len][data1][data2]..[dataLEN] */
int FAST_FUNC add_option_string(uint8_t *optionptr, uint8_t *string)
{
int end = end_option(optionptr);
/* end position + string length + option code/length + end option */
if (end + string[OPT_LEN] + 2 + 1 >= DHCP_OPTIONS_BUFSIZE) {
bb_error_msg("option 0x%02x did not fit into the packet",
string[OPT_CODE]);
return 0;
}
log_option("Adding option", string);
memcpy(optionptr + end, string, string[OPT_LEN] + 2);
optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
return string[OPT_LEN] + 2;
}
/* add a one to four byte option to a packet */
int FAST_FUNC add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
{
const struct dhcp_option *dh;
for (dh = dhcp_options; dh->code; dh++) {
if (dh->code == code) {
uint8_t option[6], len;
option[OPT_CODE] = code;
len = dhcp_option_lengths[dh->flags & TYPE_MASK];
option[OPT_LEN] = len;
if (BB_BIG_ENDIAN)
data <<= 8 * (4 - len);
/* Assignment is unaligned! */
move_to_unaligned32(&option[OPT_DATA], data);
return add_option_string(optionptr, option);
}
}
bb_error_msg("cannot add option 0x%02x", code);
return 0;
}
|
