blob: 76d6e373703e91bc33a4229ea716dc5889bea6bb [file] [log] [blame]
"Robert P. J. Day"63fc1a92006-07-02 19:47:05 +00001/* vi: set sw=4 ts=4: */
Mike Frysinger7031f622006-05-08 03:20:50 +00002/*
3 * options.c -- DHCP server option packet tools
4 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
Denis Vlasenkodb12d1d2008-12-07 00:52:58 +00005 *
6 * Licensed under GPLv2, see file LICENSE in this tarball for details.
Mike Frysinger7031f622006-05-08 03:20:50 +00007 */
8
Mike Frysinger7031f622006-05-08 03:20:50 +00009#include "common.h"
10#include "dhcpd.h"
11#include "options.h"
Mike Frysinger7031f622006-05-08 03:20:50 +000012
13
Denis Vlasenko35ff7462007-11-28 19:23:12 +000014/* Supported options are easily added here */
Denis Vlasenkoc90c3f32006-11-23 12:57:49 +000015const struct dhcp_option dhcp_options[] = {
Denis Vlasenko19183682007-12-10 07:03:38 +000016 /* flags code */
17 { OPTION_IP | OPTION_REQ, 0x01 }, /* DHCP_SUBNET */
18 { OPTION_S32 , 0x02 }, /* DHCP_TIME_OFFSET */
19 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03 }, /* DHCP_ROUTER */
20 { OPTION_IP | OPTION_LIST , 0x04 }, /* DHCP_TIME_SERVER */
21 { OPTION_IP | OPTION_LIST , 0x05 }, /* DHCP_NAME_SERVER */
22 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06 }, /* DHCP_DNS_SERVER */
23 { OPTION_IP | OPTION_LIST , 0x07 }, /* DHCP_LOG_SERVER */
24 { OPTION_IP | OPTION_LIST , 0x08 }, /* DHCP_COOKIE_SERVER */
25 { OPTION_IP | OPTION_LIST , 0x09 }, /* DHCP_LPR_SERVER */
26 { OPTION_STRING | OPTION_REQ, 0x0c }, /* DHCP_HOST_NAME */
27 { OPTION_U16 , 0x0d }, /* DHCP_BOOT_SIZE */
28 { OPTION_STRING | OPTION_LIST | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME */
29 { OPTION_IP , 0x10 }, /* DHCP_SWAP_SERVER */
30 { OPTION_STRING , 0x11 }, /* DHCP_ROOT_PATH */
31 { OPTION_U8 , 0x17 }, /* DHCP_IP_TTL */
32 { OPTION_U16 , 0x1a }, /* DHCP_MTU */
33 { OPTION_IP | OPTION_REQ, 0x1c }, /* DHCP_BROADCAST */
34 { OPTION_STRING , 0x28 }, /* nisdomain */
35 { OPTION_IP | OPTION_LIST , 0x29 }, /* nissrv */
36 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a }, /* DHCP_NTP_SERVER */
37 { OPTION_IP | OPTION_LIST , 0x2c }, /* DHCP_WINS_SERVER */
38 { OPTION_IP , 0x32 }, /* DHCP_REQUESTED_IP */
39 { OPTION_U32 , 0x33 }, /* DHCP_LEASE_TIME */
40 { OPTION_U8 , 0x35 }, /* dhcptype */
41 { OPTION_IP , 0x36 }, /* DHCP_SERVER_ID */
42 { OPTION_STRING , 0x38 }, /* DHCP_MESSAGE */
43 { OPTION_STRING , 0x3C }, /* DHCP_VENDOR */
44 { OPTION_STRING , 0x3D }, /* DHCP_CLIENT_ID */
45 { OPTION_STRING , 0x42 }, /* tftp */
46 { OPTION_STRING , 0x43 }, /* bootfile */
47 { OPTION_STRING , 0x4D }, /* userclass */
Denis Vlasenko35a064b2008-11-06 00:49:59 +000048#if ENABLE_FEATURE_UDHCP_RFC3397
Denis Vlasenko19183682007-12-10 07:03:38 +000049 { OPTION_STR1035 | OPTION_LIST , 0x77 }, /* search */
Denis Vlasenko50664732007-02-27 21:15:08 +000050#endif
Denis Vlasenkoc90c3f32006-11-23 12:57:49 +000051 /* MSIE's "Web Proxy Autodiscovery Protocol" support */
Denis Vlasenko19183682007-12-10 07:03:38 +000052 { OPTION_STRING , 0xfc }, /* wpad */
Denis Vlasenkob539c842007-11-29 08:17:45 +000053
54 /* Options below have no match in dhcp_option_strings[],
55 * are not passed to dhcpc scripts, and cannot be specified
56 * with "option XXX YYY" syntax in dhcpd config file. */
57
Denis Vlasenko19183682007-12-10 07:03:38 +000058 { OPTION_U16 , 0x39 }, /* DHCP_MAX_SIZE */
Denis Vlasenkob539c842007-11-29 08:17:45 +000059 { } /* zeroed terminating entry */
Mike Frysinger7031f622006-05-08 03:20:50 +000060};
61
Denis Vlasenkob539c842007-11-29 08:17:45 +000062/* Used for converting options from incoming packets to env variables
63 * for udhcpc stript */
64/* Must match dhcp_options[] order */
65const char dhcp_option_strings[] ALIGN1 =
66 "subnet" "\0" /* DHCP_SUBNET */
67 "timezone" "\0" /* DHCP_TIME_OFFSET */
68 "router" "\0" /* DHCP_ROUTER */
Denis Vlasenko19183682007-12-10 07:03:38 +000069 "timesrv" "\0" /* DHCP_TIME_SERVER */
70 "namesrv" "\0" /* DHCP_NAME_SERVER */
Denis Vlasenkob539c842007-11-29 08:17:45 +000071 "dns" "\0" /* DHCP_DNS_SERVER */
Denis Vlasenko19183682007-12-10 07:03:38 +000072 "logsrv" "\0" /* DHCP_LOG_SERVER */
73 "cookiesrv" "\0" /* DHCP_COOKIE_SERVER */
74 "lprsrv" "\0" /* DHCP_LPR_SERVER */
Denis Vlasenkob539c842007-11-29 08:17:45 +000075 "hostname" "\0" /* DHCP_HOST_NAME */
76 "bootsize" "\0" /* DHCP_BOOT_SIZE */
77 "domain" "\0" /* DHCP_DOMAIN_NAME */
Denis Vlasenko19183682007-12-10 07:03:38 +000078 "swapsrv" "\0" /* DHCP_SWAP_SERVER */
Denis Vlasenkob539c842007-11-29 08:17:45 +000079 "rootpath" "\0" /* DHCP_ROOT_PATH */
80 "ipttl" "\0" /* DHCP_IP_TTL */
81 "mtu" "\0" /* DHCP_MTU */
82 "broadcast" "\0" /* DHCP_BROADCAST */
Denis Vlasenko19183682007-12-10 07:03:38 +000083 "nisdomain" "\0" /* */
84 "nissrv" "\0" /* */
85 "ntpsrv" "\0" /* DHCP_NTP_SERVER */
86 "wins" "\0" /* DHCP_WINS_SERVER */
87 "requestip" "\0" /* DHCP_REQUESTED_IP */
88 "lease" "\0" /* DHCP_LEASE_TIME */
89 "dhcptype" "\0" /* */
90 "serverid" "\0" /* DHCP_SERVER_ID */
Denis Vlasenkob539c842007-11-29 08:17:45 +000091 "message" "\0" /* DHCP_MESSAGE */
92 "vendorclass" "\0" /* DHCP_VENDOR */
93 "clientid" "\0" /* DHCP_CLIENT_ID */
94 "tftp" "\0"
95 "bootfile" "\0"
96 "userclass" "\0"
Denis Vlasenko35a064b2008-11-06 00:49:59 +000097#if ENABLE_FEATURE_UDHCP_RFC3397
Denis Vlasenkob539c842007-11-29 08:17:45 +000098 "search" "\0"
99#endif
100 /* MSIE's "Web Proxy Autodiscovery Protocol" support */
101 "wpad" "\0"
102 ;
103
Denis Vlasenko35ff7462007-11-28 19:23:12 +0000104
Mike Frysinger7031f622006-05-08 03:20:50 +0000105/* Lengths of the different option types */
Denis Vlasenkob539c842007-11-29 08:17:45 +0000106const uint8_t dhcp_option_lengths[] ALIGN1 = {
Denis Vlasenkoc90c3f32006-11-23 12:57:49 +0000107 [OPTION_IP] = 4,
108 [OPTION_IP_PAIR] = 8,
109 [OPTION_BOOLEAN] = 1,
110 [OPTION_STRING] = 1,
Denis Vlasenko35a064b2008-11-06 00:49:59 +0000111#if ENABLE_FEATURE_UDHCP_RFC3397
Denis Vlasenko50664732007-02-27 21:15:08 +0000112 [OPTION_STR1035] = 1,
113#endif
Denis Vlasenkoc90c3f32006-11-23 12:57:49 +0000114 [OPTION_U8] = 1,
115 [OPTION_U16] = 2,
116 [OPTION_S16] = 2,
117 [OPTION_U32] = 4,
Denys Vlasenko7895b912009-07-03 16:59:59 +0200118 [OPTION_S32] = 4,
Mike Frysinger7031f622006-05-08 03:20:50 +0000119};
120
121
Denys Vlasenko6947d2c2009-06-17 13:24:03 +0200122#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
123static void log_option(const char *pfx, const uint8_t *opt)
124{
125 if (dhcp_verbose >= 2) {
126 char buf[256 * 2 + 2];
127 *bin2hex(buf, (void*) (opt + OPT_DATA), opt[OPT_LEN]) = '\0';
128 bb_info_msg("%s: 0x%02x %s", pfx, opt[OPT_CODE], buf);
129 }
130}
131#else
132# define log_option(pfx, opt) ((void)0)
133#endif
134
135
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000136/* get an option with bounds checking (warning, result is not aligned). */
Denys Vlasenko31af3d52009-06-17 11:57:09 +0200137uint8_t* FAST_FUNC get_option(struct dhcp_packet *packet, int code)
Mike Frysinger7031f622006-05-08 03:20:50 +0000138{
Mike Frysinger7031f622006-05-08 03:20:50 +0000139 uint8_t *optionptr;
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000140 int len;
141 int rem;
142 int overload = 0;
143 enum {
144 FILE_FIELD101 = FILE_FIELD * 0x101,
145 SNAME_FIELD101 = SNAME_FIELD * 0x101,
146 };
Mike Frysinger7031f622006-05-08 03:20:50 +0000147
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000148 /* option bytes: [code][len][data1][data2]..[dataLEN] */
Mike Frysinger7031f622006-05-08 03:20:50 +0000149 optionptr = packet->options;
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000150 rem = sizeof(packet->options);
Denis Vlasenko6884f662007-11-23 00:08:54 +0000151 while (1) {
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000152 if (rem <= 0) {
153 bb_error_msg("bogus packet, malformed option field");
Mike Frysinger7031f622006-05-08 03:20:50 +0000154 return NULL;
155 }
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000156 if (optionptr[OPT_CODE] == DHCP_PADDING) {
157 rem--;
158 optionptr++;
159 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +0000160 }
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000161 if (optionptr[OPT_CODE] == DHCP_END) {
162 if ((overload & FILE_FIELD101) == FILE_FIELD) {
163 /* can use packet->file, and didn't look at it yet */
164 overload |= FILE_FIELD101; /* "we looked at it" */
Mike Frysinger7031f622006-05-08 03:20:50 +0000165 optionptr = packet->file;
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000166 rem = sizeof(packet->file);
167 continue;
168 }
169 if ((overload & SNAME_FIELD101) == SNAME_FIELD) {
170 /* can use packet->sname, and didn't look at it yet */
171 overload |= SNAME_FIELD101; /* "we looked at it" */
Mike Frysinger7031f622006-05-08 03:20:50 +0000172 optionptr = packet->sname;
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000173 rem = sizeof(packet->sname);
174 continue;
175 }
Denys Vlasenko31af3d52009-06-17 11:57:09 +0200176 break;
Mike Frysinger7031f622006-05-08 03:20:50 +0000177 }
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000178 len = 2 + optionptr[OPT_LEN];
179 rem -= len;
180 if (rem < 0)
181 continue; /* complain and return NULL */
182
Denys Vlasenko31af3d52009-06-17 11:57:09 +0200183 if (optionptr[OPT_CODE] == code) {
Denys Vlasenko6947d2c2009-06-17 13:24:03 +0200184 log_option("Option found", optionptr);
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000185 return optionptr + OPT_DATA;
Denys Vlasenko31af3d52009-06-17 11:57:09 +0200186 }
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000187
188 if (optionptr[OPT_CODE] == DHCP_OPTION_OVERLOAD) {
189 overload |= optionptr[OPT_DATA];
190 /* fall through */
191 }
192 optionptr += len;
Mike Frysinger7031f622006-05-08 03:20:50 +0000193 }
Denys Vlasenko31af3d52009-06-17 11:57:09 +0200194
195 /* log3 because udhcpc uses it a lot - very noisy */
196 log3("Option 0x%02x not found", code);
Mike Frysinger7031f622006-05-08 03:20:50 +0000197 return NULL;
198}
199
200
201/* return the position of the 'end' option (no bounds checking) */
Denis Vlasenkof1980f62008-09-26 09:34:59 +0000202int FAST_FUNC end_option(uint8_t *optionptr)
Mike Frysinger7031f622006-05-08 03:20:50 +0000203{
204 int i = 0;
205
206 while (optionptr[i] != DHCP_END) {
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000207 if (optionptr[i] != DHCP_PADDING)
208 i += optionptr[i + OPT_LEN] + 1;
209 i++;
Mike Frysinger7031f622006-05-08 03:20:50 +0000210 }
211 return i;
212}
213
214
Denis Vlasenkobd79c3d2009-04-01 12:36:09 +0000215/* add an option string to the options */
216/* option bytes: [code][len][data1][data2]..[dataLEN] */
Denis Vlasenkof1980f62008-09-26 09:34:59 +0000217int FAST_FUNC add_option_string(uint8_t *optionptr, uint8_t *string)
Mike Frysinger7031f622006-05-08 03:20:50 +0000218{
219 int end = end_option(optionptr);
220
221 /* end position + string length + option code/length + end option */
Denis Vlasenko72e76042007-11-25 03:15:24 +0000222 if (end + string[OPT_LEN] + 2 + 1 >= DHCP_OPTIONS_BUFSIZE) {
Denis Vlasenkoe1a0d482006-10-20 13:28:22 +0000223 bb_error_msg("option 0x%02x did not fit into the packet",
Denis Vlasenko3538b9a2006-09-06 18:36:50 +0000224 string[OPT_CODE]);
Mike Frysinger7031f622006-05-08 03:20:50 +0000225 return 0;
226 }
Denys Vlasenko6947d2c2009-06-17 13:24:03 +0200227 log_option("Adding option", string);
Mike Frysinger7031f622006-05-08 03:20:50 +0000228 memcpy(optionptr + end, string, string[OPT_LEN] + 2);
229 optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
230 return string[OPT_LEN] + 2;
231}
232
233
234/* add a one to four byte option to a packet */
Denis Vlasenkof1980f62008-09-26 09:34:59 +0000235int FAST_FUNC add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
Mike Frysinger7031f622006-05-08 03:20:50 +0000236{
Denis Vlasenkoc90c3f32006-11-23 12:57:49 +0000237 const struct dhcp_option *dh;
Mike Frysinger7031f622006-05-08 03:20:50 +0000238
Denis Vlasenkoc90c3f32006-11-23 12:57:49 +0000239 for (dh = dhcp_options; dh->code; dh++) {
Mike Frysinger7031f622006-05-08 03:20:50 +0000240 if (dh->code == code) {
241 uint8_t option[6], len;
242
243 option[OPT_CODE] = code;
Denis Vlasenkob539c842007-11-29 08:17:45 +0000244 len = dhcp_option_lengths[dh->flags & TYPE_MASK];
Mike Frysinger7031f622006-05-08 03:20:50 +0000245 option[OPT_LEN] = len;
Denis Vlasenkob539c842007-11-29 08:17:45 +0000246 if (BB_BIG_ENDIAN)
247 data <<= 8 * (4 - len);
Denis Vlasenkoefb545b2008-12-08 22:56:18 +0000248 /* Assignment is unaligned! */
249 move_to_unaligned32(&option[OPT_DATA], data);
Mike Frysinger7031f622006-05-08 03:20:50 +0000250 return add_option_string(optionptr, option);
251 }
252 }
253
Denis Vlasenkoea620772006-10-14 02:23:43 +0000254 bb_error_msg("cannot add option 0x%02x", code);
Mike Frysinger7031f622006-05-08 03:20:50 +0000255 return 0;
256}