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.
14 /* Supported options are easily added here.
15 * See RFC2132 for more options.
16 * OPTION_REQ: these options are requested by udhcpc (unless -o).
18 const struct dhcp_option dhcp_options[] = {
20 { OPTION_IP | OPTION_REQ, 0x01 }, /* DHCP_SUBNET */
21 { OPTION_S32 , 0x02 }, /* DHCP_TIME_OFFSET */
22 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03 }, /* DHCP_ROUTER */
23 // { OPTION_IP | OPTION_LIST , 0x04 }, /* DHCP_TIME_SERVER */
24 // { OPTION_IP | OPTION_LIST , 0x05 }, /* DHCP_NAME_SERVER */
25 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06 }, /* DHCP_DNS_SERVER */
26 // { OPTION_IP | OPTION_LIST , 0x07 }, /* DHCP_LOG_SERVER */
27 // { OPTION_IP | OPTION_LIST , 0x08 }, /* DHCP_COOKIE_SERVER */
28 { OPTION_IP | OPTION_LIST , 0x09 }, /* DHCP_LPR_SERVER */
29 { OPTION_STRING | OPTION_REQ, 0x0c }, /* DHCP_HOST_NAME */
30 { OPTION_U16 , 0x0d }, /* DHCP_BOOT_SIZE */
31 { OPTION_STRING | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME */
32 { OPTION_IP , 0x10 }, /* DHCP_SWAP_SERVER */
33 { OPTION_STRING , 0x11 }, /* DHCP_ROOT_PATH */
34 { OPTION_U8 , 0x17 }, /* DHCP_IP_TTL */
35 { OPTION_U16 , 0x1a }, /* DHCP_MTU */
36 { OPTION_IP | OPTION_REQ, 0x1c }, /* DHCP_BROADCAST */
37 { OPTION_STRING , 0x28 }, /* DHCP_NIS_DOMAIN */
38 { OPTION_IP | OPTION_LIST , 0x29 }, /* DHCP_NIS_SERVER */
39 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a }, /* DHCP_NTP_SERVER */
40 { OPTION_IP | OPTION_LIST , 0x2c }, /* DHCP_WINS_SERVER */
41 { OPTION_U32 , 0x33 }, /* DHCP_LEASE_TIME */
42 { OPTION_IP , 0x36 }, /* DHCP_SERVER_ID */
43 { OPTION_STRING , 0x38 }, /* DHCP_ERR_MESSAGE */
44 //TODO: must be combined with 'sname' and 'file' handling:
45 { OPTION_STRING , 0x42 }, /* DHCP_TFTP_SERVER_NAME */
46 { OPTION_STRING , 0x43 }, /* DHCP_BOOT_FILE */
47 //TODO: not a string, but a set of LASCII strings:
48 // { OPTION_STRING , 0x4D }, /* DHCP_USER_CLASS */
49 #if ENABLE_FEATURE_UDHCP_RFC3397
50 { OPTION_STR1035 | OPTION_LIST , 0x77 }, /* DHCP_DOMAIN_SEARCH */
52 { OPTION_STATIC_ROUTES , 0x79 }, /* DHCP_STATIC_ROUTES */
53 { OPTION_STRING , 0xfc }, /* DHCP_WPAD */
55 /* Options below have no match in dhcp_option_strings[],
56 * are not passed to dhcpc scripts, and cannot be specified
57 * with "option XXX YYY" syntax in dhcpd config file.
58 * These entries are only used internally by udhcp[cd]
59 * to correctly encode options into packets.
62 { OPTION_IP , 0x32 }, /* DHCP_REQUESTED_IP */
63 { OPTION_U8 , 0x35 }, /* DHCP_MESSAGE_TYPE */
64 { OPTION_U16 , 0x39 }, /* DHCP_MAX_SIZE */
65 { OPTION_STRING , 0x3c }, /* DHCP_VENDOR */
66 //FIXME: handling of this option is not exactly correct:
67 { OPTION_STRING , 0x3d }, /* DHCP_CLIENT_ID */
68 { 0, 0 } /* zeroed terminating entry */
71 /* Used for converting options from incoming packets to env variables
72 * for udhcpc stript, and for setting options for udhcpd via
73 * "opt OPTION_NAME OPTION_VALUE" directives in udhcpd.conf file.
75 /* Must match dhcp_options[] order */
76 const char dhcp_option_strings[] ALIGN1 =
77 "subnet" "\0" /* DHCP_SUBNET */
78 "timezone" "\0" /* DHCP_TIME_OFFSET */
79 "router" "\0" /* DHCP_ROUTER */
80 // "timesrv" "\0" /* DHCP_TIME_SERVER */
81 // "namesrv" "\0" /* DHCP_NAME_SERVER */
82 "dns" "\0" /* DHCP_DNS_SERVER */
83 // "logsrv" "\0" /* DHCP_LOG_SERVER */
84 // "cookiesrv" "\0" /* DHCP_COOKIE_SERVER */
85 "lprsrv" "\0" /* DHCP_LPR_SERVER */
86 "hostname" "\0" /* DHCP_HOST_NAME */
87 "bootsize" "\0" /* DHCP_BOOT_SIZE */
88 "domain" "\0" /* DHCP_DOMAIN_NAME */
89 "swapsrv" "\0" /* DHCP_SWAP_SERVER */
90 "rootpath" "\0" /* DHCP_ROOT_PATH */
91 "ipttl" "\0" /* DHCP_IP_TTL */
92 "mtu" "\0" /* DHCP_MTU */
93 "broadcast" "\0" /* DHCP_BROADCAST */
94 "nisdomain" "\0" /* DHCP_NIS_DOMAIN */
95 "nissrv" "\0" /* DHCP_NIS_SERVER */
96 "ntpsrv" "\0" /* DHCP_NTP_SERVER */
97 "wins" "\0" /* DHCP_WINS_SERVER */
98 "lease" "\0" /* DHCP_LEASE_TIME */
99 "serverid" "\0" /* DHCP_SERVER_ID */
100 "message" "\0" /* DHCP_ERR_MESSAGE */
101 "tftp" "\0" /* DHCP_TFTP_SERVER_NAME */
102 "bootfile" "\0" /* DHCP_BOOT_FILE */
103 // "userclass" "\0" /* DHCP_USER_CLASS */
104 #if ENABLE_FEATURE_UDHCP_RFC3397
105 "search" "\0" /* DHCP_DOMAIN_SEARCH */
107 // "staticroutes" is only used to set udhcpc environment, it doesn't work
108 // in udhcpd.conf since OPTION_STATIC_ROUTES is not handled yet
109 // by "string->option" conversion code:
110 "staticroutes" "\0"/* DHCP_STATIC_ROUTES */
111 "wpad" "\0" /* DHCP_WPAD */
115 /* Lengths of the different option types */
116 const uint8_t dhcp_option_lengths[] ALIGN1 = {
118 [OPTION_IP_PAIR] = 8,
119 [OPTION_BOOLEAN] = 1,
121 #if ENABLE_FEATURE_UDHCP_RFC3397
122 [OPTION_STR1035] = 1,
129 /* Just like OPTION_STRING, we use minimum length here */
130 [OPTION_STATIC_ROUTES] = 5,
134 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
135 static void log_option(const char *pfx, const uint8_t *opt)
137 if (dhcp_verbose >= 2) {
138 char buf[256 * 2 + 2];
139 *bin2hex(buf, (void*) (opt + OPT_DATA), opt[OPT_LEN]) = '\0';
140 bb_info_msg("%s: 0x%02x %s", pfx, opt[OPT_CODE], buf);
144 # define log_option(pfx, opt) ((void)0)
148 /* get an option with bounds checking (warning, result is not aligned). */
149 uint8_t* FAST_FUNC get_option(struct dhcp_packet *packet, int code)
156 FILE_FIELD101 = FILE_FIELD * 0x101,
157 SNAME_FIELD101 = SNAME_FIELD * 0x101,
160 /* option bytes: [code][len][data1][data2]..[dataLEN] */
161 optionptr = packet->options;
162 rem = sizeof(packet->options);
165 bb_error_msg("bogus packet, malformed option field");
168 if (optionptr[OPT_CODE] == DHCP_PADDING) {
173 if (optionptr[OPT_CODE] == DHCP_END) {
174 if ((overload & FILE_FIELD101) == FILE_FIELD) {
175 /* can use packet->file, and didn't look at it yet */
176 overload |= FILE_FIELD101; /* "we looked at it" */
177 optionptr = packet->file;
178 rem = sizeof(packet->file);
181 if ((overload & SNAME_FIELD101) == SNAME_FIELD) {
182 /* can use packet->sname, and didn't look at it yet */
183 overload |= SNAME_FIELD101; /* "we looked at it" */
184 optionptr = packet->sname;
185 rem = sizeof(packet->sname);
190 len = 2 + optionptr[OPT_LEN];
193 continue; /* complain and return NULL */
195 if (optionptr[OPT_CODE] == code) {
196 log_option("Option found", optionptr);
197 return optionptr + OPT_DATA;
200 if (optionptr[OPT_CODE] == DHCP_OPTION_OVERLOAD) {
201 overload |= optionptr[OPT_DATA];
207 /* log3 because udhcpc uses it a lot - very noisy */
208 log3("Option 0x%02x not found", code);
213 /* return the position of the 'end' option (no bounds checking) */
214 int FAST_FUNC end_option(uint8_t *optionptr)
218 while (optionptr[i] != DHCP_END) {
219 if (optionptr[i] != DHCP_PADDING)
220 i += optionptr[i + OPT_LEN] + 1;
227 /* add an option string to the options */
228 /* option bytes: [code][len][data1][data2]..[dataLEN] */
229 void FAST_FUNC add_option_string(uint8_t *optionptr, uint8_t *string)
231 int end = end_option(optionptr);
233 /* end position + string length + option code/length + end option */
234 if (end + string[OPT_LEN] + 2 + 1 >= DHCP_OPTIONS_BUFSIZE) {
235 bb_error_msg("option 0x%02x did not fit into the packet",
239 log_option("Adding option", string);
240 memcpy(optionptr + end, string, string[OPT_LEN] + 2);
241 optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
245 /* add a one to four byte option to a packet */
246 void FAST_FUNC add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
248 const struct dhcp_option *dh;
250 for (dh = dhcp_options; dh->code; dh++) {
251 if (dh->code == code) {
252 uint8_t option[6], len;
254 option[OPT_CODE] = code;
255 len = dhcp_option_lengths[dh->flags & TYPE_MASK];
256 option[OPT_LEN] = len;
258 data <<= 8 * (4 - len);
259 /* Assignment is unaligned! */
260 move_to_unaligned32(&option[OPT_DATA], data);
261 add_option_string(optionptr, option);
266 bb_error_msg("can't add option 0x%02x", code);