1 /* vi: set sw=4 ts=4: */
3 * options.c -- DHCP server option packet tools
4 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
6 * Licensed under GPLv2, see file LICENSE in this tarball for details.
12 /* Supported options are easily added here.
13 * See RFC2132 for more options.
14 * OPTION_REQ: these options are requested by udhcpc (unless -o).
16 const struct dhcp_option dhcp_options[] = {
18 { OPTION_IP | OPTION_REQ, 0x01 }, /* DHCP_SUBNET */
19 { OPTION_S32 , 0x02 }, /* DHCP_TIME_OFFSET */
20 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03 }, /* DHCP_ROUTER */
21 // { OPTION_IP | OPTION_LIST , 0x04 }, /* DHCP_TIME_SERVER */
22 // { OPTION_IP | OPTION_LIST , 0x05 }, /* DHCP_NAME_SERVER */
23 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06 }, /* DHCP_DNS_SERVER */
24 // { OPTION_IP | OPTION_LIST , 0x07 }, /* DHCP_LOG_SERVER */
25 // { OPTION_IP | OPTION_LIST , 0x08 }, /* DHCP_COOKIE_SERVER */
26 { OPTION_IP | OPTION_LIST , 0x09 }, /* DHCP_LPR_SERVER */
27 { OPTION_STRING | OPTION_REQ, 0x0c }, /* DHCP_HOST_NAME */
28 { OPTION_U16 , 0x0d }, /* DHCP_BOOT_SIZE */
29 { OPTION_STRING | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME */
30 { OPTION_IP , 0x10 }, /* DHCP_SWAP_SERVER */
31 { OPTION_STRING , 0x11 }, /* DHCP_ROOT_PATH */
32 { OPTION_U8 , 0x17 }, /* DHCP_IP_TTL */
33 { OPTION_U16 , 0x1a }, /* DHCP_MTU */
34 { OPTION_IP | OPTION_REQ, 0x1c }, /* DHCP_BROADCAST */
35 { OPTION_STRING , 0x28 }, /* DHCP_NIS_DOMAIN */
36 { OPTION_IP | OPTION_LIST , 0x29 }, /* DHCP_NIS_SERVER */
37 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a }, /* DHCP_NTP_SERVER */
38 { OPTION_IP | OPTION_LIST , 0x2c }, /* DHCP_WINS_SERVER */
39 { OPTION_U32 , 0x33 }, /* DHCP_LEASE_TIME */
40 { OPTION_IP , 0x36 }, /* DHCP_SERVER_ID */
41 { OPTION_STRING , 0x38 }, /* DHCP_ERR_MESSAGE */
42 //TODO: must be combined with 'sname' and 'file' handling:
43 { OPTION_STRING , 0x42 }, /* DHCP_TFTP_SERVER_NAME */
44 { OPTION_STRING , 0x43 }, /* DHCP_BOOT_FILE */
45 //TODO: not a string, but a set of LASCII strings:
46 // { OPTION_STRING , 0x4D }, /* DHCP_USER_CLASS */
47 #if ENABLE_FEATURE_UDHCP_RFC3397
48 { OPTION_STR1035 | OPTION_LIST , 0x77 }, /* DHCP_DOMAIN_SEARCH */
50 { OPTION_STATIC_ROUTES , 0x79 }, /* DHCP_STATIC_ROUTES */
51 { OPTION_STRING , 0xfc }, /* DHCP_WPAD */
53 /* Options below have no match in dhcp_option_strings[],
54 * are not passed to dhcpc scripts, and cannot be specified
55 * with "option XXX YYY" syntax in dhcpd config file.
56 * These entries are only used internally by udhcp[cd]
57 * to correctly encode options into packets.
60 { OPTION_IP , 0x32 }, /* DHCP_REQUESTED_IP */
61 { OPTION_U8 , 0x35 }, /* DHCP_MESSAGE_TYPE */
62 { OPTION_U16 , 0x39 }, /* DHCP_MAX_SIZE */
63 { OPTION_STRING , 0x3c }, /* DHCP_VENDOR */
64 //FIXME: handling of this option is not exactly correct:
65 { OPTION_STRING , 0x3d }, /* DHCP_CLIENT_ID */
66 { 0, 0 } /* zeroed terminating entry */
69 /* Used for converting options from incoming packets to env variables
70 * for udhcpc stript, and for setting options for udhcpd via
71 * "opt OPTION_NAME OPTION_VALUE" directives in udhcpd.conf file.
73 /* Must match dhcp_options[] order */
74 const char dhcp_option_strings[] ALIGN1 =
75 "subnet" "\0" /* DHCP_SUBNET */
76 "timezone" "\0" /* DHCP_TIME_OFFSET */
77 "router" "\0" /* DHCP_ROUTER */
78 // "timesrv" "\0" /* DHCP_TIME_SERVER */
79 // "namesrv" "\0" /* DHCP_NAME_SERVER */
80 "dns" "\0" /* DHCP_DNS_SERVER */
81 // "logsrv" "\0" /* DHCP_LOG_SERVER */
82 // "cookiesrv" "\0" /* DHCP_COOKIE_SERVER */
83 "lprsrv" "\0" /* DHCP_LPR_SERVER */
84 "hostname" "\0" /* DHCP_HOST_NAME */
85 "bootsize" "\0" /* DHCP_BOOT_SIZE */
86 "domain" "\0" /* DHCP_DOMAIN_NAME */
87 "swapsrv" "\0" /* DHCP_SWAP_SERVER */
88 "rootpath" "\0" /* DHCP_ROOT_PATH */
89 "ipttl" "\0" /* DHCP_IP_TTL */
90 "mtu" "\0" /* DHCP_MTU */
91 "broadcast" "\0" /* DHCP_BROADCAST */
92 "nisdomain" "\0" /* DHCP_NIS_DOMAIN */
93 "nissrv" "\0" /* DHCP_NIS_SERVER */
94 "ntpsrv" "\0" /* DHCP_NTP_SERVER */
95 "wins" "\0" /* DHCP_WINS_SERVER */
96 "lease" "\0" /* DHCP_LEASE_TIME */
97 "serverid" "\0" /* DHCP_SERVER_ID */
98 "message" "\0" /* DHCP_ERR_MESSAGE */
99 "tftp" "\0" /* DHCP_TFTP_SERVER_NAME */
100 "bootfile" "\0" /* DHCP_BOOT_FILE */
101 // "userclass" "\0" /* DHCP_USER_CLASS */
102 #if ENABLE_FEATURE_UDHCP_RFC3397
103 "search" "\0" /* DHCP_DOMAIN_SEARCH */
105 // "staticroutes" is only used to set udhcpc environment, it doesn't work
106 // in udhcpd.conf since OPTION_STATIC_ROUTES is not handled yet
107 // by "string->option" conversion code:
108 "staticroutes" "\0"/* DHCP_STATIC_ROUTES */
109 "wpad" "\0" /* DHCP_WPAD */
112 /* Lengths of the different option types */
113 const uint8_t dhcp_option_lengths[] ALIGN1 = {
115 [OPTION_IP_PAIR] = 8,
116 [OPTION_BOOLEAN] = 1,
118 #if ENABLE_FEATURE_UDHCP_RFC3397
119 [OPTION_STR1035] = 1,
126 /* Just like OPTION_STRING, we use minimum length here */
127 [OPTION_STATIC_ROUTES] = 5,
131 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
132 static void log_option(const char *pfx, const uint8_t *opt)
134 if (dhcp_verbose >= 2) {
135 char buf[256 * 2 + 2];
136 *bin2hex(buf, (void*) (opt + OPT_DATA), opt[OPT_LEN]) = '\0';
137 bb_info_msg("%s: 0x%02x %s", pfx, opt[OPT_CODE], buf);
141 # define log_option(pfx, opt) ((void)0)
144 /* get an option with bounds checking (warning, result is not aligned). */
145 uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code)
152 FILE_FIELD101 = FILE_FIELD * 0x101,
153 SNAME_FIELD101 = SNAME_FIELD * 0x101,
156 /* option bytes: [code][len][data1][data2]..[dataLEN] */
157 optionptr = packet->options;
158 rem = sizeof(packet->options);
161 bb_error_msg("bad packet, malformed option field");
164 if (optionptr[OPT_CODE] == DHCP_PADDING) {
169 if (optionptr[OPT_CODE] == DHCP_END) {
170 if ((overload & FILE_FIELD101) == FILE_FIELD) {
171 /* can use packet->file, and didn't look at it yet */
172 overload |= FILE_FIELD101; /* "we looked at it" */
173 optionptr = packet->file;
174 rem = sizeof(packet->file);
177 if ((overload & SNAME_FIELD101) == SNAME_FIELD) {
178 /* can use packet->sname, and didn't look at it yet */
179 overload |= SNAME_FIELD101; /* "we looked at it" */
180 optionptr = packet->sname;
181 rem = sizeof(packet->sname);
186 len = 2 + optionptr[OPT_LEN];
189 continue; /* complain and return NULL */
191 if (optionptr[OPT_CODE] == code) {
192 log_option("Option found", optionptr);
193 return optionptr + OPT_DATA;
196 if (optionptr[OPT_CODE] == DHCP_OPTION_OVERLOAD) {
197 overload |= optionptr[OPT_DATA];
203 /* log3 because udhcpc uses it a lot - very noisy */
204 log3("Option 0x%02x not found", code);
208 /* return the position of the 'end' option (no bounds checking) */
209 int FAST_FUNC udhcp_end_option(uint8_t *optionptr)
213 while (optionptr[i] != DHCP_END) {
214 if (optionptr[i] != DHCP_PADDING)
215 i += optionptr[i + OPT_LEN] + 1;
221 /* add an option string to the options */
222 /* option bytes: [code][len][data1][data2]..[dataLEN] */
223 void FAST_FUNC udhcp_add_option_string(uint8_t *optionptr, uint8_t *string)
225 int end = udhcp_end_option(optionptr);
227 /* end position + string length + option code/length + end option */
228 if (end + string[OPT_LEN] + 2 + 1 >= DHCP_OPTIONS_BUFSIZE) {
229 bb_error_msg("option 0x%02x did not fit into the packet",
233 log_option("Adding option", string);
234 memcpy(optionptr + end, string, string[OPT_LEN] + 2);
235 optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
238 /* add a one to four byte option to a packet */
239 void FAST_FUNC udhcp_add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
241 const struct dhcp_option *dh;
243 for (dh = dhcp_options; dh->code; dh++) {
244 if (dh->code == code) {
245 uint8_t option[6], len;
247 option[OPT_CODE] = code;
248 len = dhcp_option_lengths[dh->flags & OPTION_TYPE_MASK];
249 option[OPT_LEN] = len;
251 data <<= 8 * (4 - len);
252 /* Assignment is unaligned! */
253 move_to_unaligned32(&option[OPT_DATA], data);
254 udhcp_add_option_string(optionptr, option);
259 bb_error_msg("can't add option 0x%02x", code);