1 /* vi: set sw=4 ts=4: */
3 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
5 * Licensed under GPLv2, see file LICENSE in this source tree.
9 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
10 unsigned dhcp_verbose;
13 const uint8_t MAC_BCAST_ADDR[6] ALIGN2 = {
14 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
17 /* Supported options are easily added here.
18 * See RFC2132 for more options.
19 * OPTION_REQ: these options are requested by udhcpc (unless -o).
21 const struct dhcp_optflag dhcp_optflags[] = {
23 { OPTION_IP | OPTION_REQ, 0x01 }, /* DHCP_SUBNET */
24 { OPTION_S32 , 0x02 }, /* DHCP_TIME_OFFSET */
25 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03 }, /* DHCP_ROUTER */
26 // { OPTION_IP | OPTION_LIST , 0x04 }, /* DHCP_TIME_SERVER */
27 // { OPTION_IP | OPTION_LIST , 0x05 }, /* DHCP_NAME_SERVER */
28 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06 }, /* DHCP_DNS_SERVER */
29 // { OPTION_IP | OPTION_LIST , 0x07 }, /* DHCP_LOG_SERVER */
30 // { OPTION_IP | OPTION_LIST , 0x08 }, /* DHCP_COOKIE_SERVER */
31 { OPTION_IP | OPTION_LIST , 0x09 }, /* DHCP_LPR_SERVER */
32 { OPTION_STRING_HOST | OPTION_REQ, 0x0c }, /* DHCP_HOST_NAME */
33 { OPTION_U16 , 0x0d }, /* DHCP_BOOT_SIZE */
34 { OPTION_STRING_HOST | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME */
35 { OPTION_IP , 0x10 }, /* DHCP_SWAP_SERVER */
36 { OPTION_STRING , 0x11 }, /* DHCP_ROOT_PATH */
37 { OPTION_U8 , 0x17 }, /* DHCP_IP_TTL */
38 { OPTION_U16 , 0x1a }, /* DHCP_MTU */
39 //TODO: why do we request DHCP_BROADCAST? Can't we assume that
40 //in the unlikely case it is different from typical N.N.255.255,
41 //server would let us know anyway?
42 { OPTION_IP | OPTION_REQ, 0x1c }, /* DHCP_BROADCAST */
43 { OPTION_IP_PAIR | OPTION_LIST , 0x21 }, /* DHCP_ROUTES */
44 { OPTION_STRING_HOST , 0x28 }, /* DHCP_NIS_DOMAIN */
45 { OPTION_IP | OPTION_LIST , 0x29 }, /* DHCP_NIS_SERVER */
46 { OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a }, /* DHCP_NTP_SERVER */
47 { OPTION_IP | OPTION_LIST , 0x2c }, /* DHCP_WINS_SERVER */
48 { OPTION_U32 , 0x33 }, /* DHCP_LEASE_TIME */
49 { OPTION_IP , 0x36 }, /* DHCP_SERVER_ID */
50 { OPTION_STRING , 0x38 }, /* DHCP_ERR_MESSAGE */
51 //TODO: must be combined with 'sname' and 'file' handling:
52 { OPTION_STRING_HOST , 0x42 }, /* DHCP_TFTP_SERVER_NAME */
53 { OPTION_STRING , 0x43 }, /* DHCP_BOOT_FILE */
54 //TODO: not a string, but a set of LASCII strings:
55 // { OPTION_STRING , 0x4D }, /* DHCP_USER_CLASS */
56 #if ENABLE_FEATURE_UDHCP_RFC3397
57 { OPTION_DNS_STRING | OPTION_LIST , 0x77 }, /* DHCP_DOMAIN_SEARCH */
58 { OPTION_SIP_SERVERS , 0x78 }, /* DHCP_SIP_SERVERS */
60 { OPTION_STATIC_ROUTES | OPTION_LIST , 0x79 }, /* DHCP_STATIC_ROUTES */
61 #if ENABLE_FEATURE_UDHCP_8021Q
62 { OPTION_U16 , 0x84 }, /* DHCP_VLAN_ID */
63 { OPTION_U8 , 0x85 }, /* DHCP_VLAN_PRIORITY */
65 { OPTION_STRING , 0xd1 }, /* DHCP_PXE_CONF_FILE */
66 { OPTION_STRING , 0xd2 }, /* DHCP_PXE_PATH_PREFIX */
67 { OPTION_6RD , 0xd4 }, /* DHCP_6RD */
68 { OPTION_STATIC_ROUTES | OPTION_LIST , 0xf9 }, /* DHCP_MS_STATIC_ROUTES */
69 { OPTION_STRING , 0xfc }, /* DHCP_WPAD */
71 /* Options below have no match in dhcp_option_strings[],
72 * are not passed to dhcpc scripts, and cannot be specified
73 * with "option XXX YYY" syntax in dhcpd config file.
74 * These entries are only used internally by udhcp[cd]
75 * to correctly encode options into packets.
78 { OPTION_IP , 0x32 }, /* DHCP_REQUESTED_IP */
79 { OPTION_U8 , 0x35 }, /* DHCP_MESSAGE_TYPE */
80 { OPTION_U16 , 0x39 }, /* DHCP_MAX_SIZE */
81 //looks like these opts will work just fine even without these defs:
82 // { OPTION_STRING , 0x3c }, /* DHCP_VENDOR */
83 // /* not really a string: */
84 // { OPTION_STRING , 0x3d }, /* DHCP_CLIENT_ID */
85 { 0, 0 } /* zeroed terminating entry */
88 /* Used for converting options from incoming packets to env variables
89 * for udhcpc script, and for setting options for udhcpd via
90 * "opt OPTION_NAME OPTION_VALUE" directives in udhcpd.conf file.
92 /* Must match dhcp_optflags[] order */
93 const char dhcp_option_strings[] ALIGN1 =
94 "subnet" "\0" /* DHCP_SUBNET */
95 "timezone" "\0" /* DHCP_TIME_OFFSET */
96 "router" "\0" /* DHCP_ROUTER */
97 // "timesrv" "\0" /* DHCP_TIME_SERVER */
98 // "namesrv" "\0" /* DHCP_NAME_SERVER */
99 "dns" "\0" /* DHCP_DNS_SERVER */
100 // "logsrv" "\0" /* DHCP_LOG_SERVER */
101 // "cookiesrv" "\0" /* DHCP_COOKIE_SERVER */
102 "lprsrv" "\0" /* DHCP_LPR_SERVER */
103 "hostname" "\0" /* DHCP_HOST_NAME */
104 "bootsize" "\0" /* DHCP_BOOT_SIZE */
105 "domain" "\0" /* DHCP_DOMAIN_NAME */
106 "swapsrv" "\0" /* DHCP_SWAP_SERVER */
107 "rootpath" "\0" /* DHCP_ROOT_PATH */
108 "ipttl" "\0" /* DHCP_IP_TTL */
109 "mtu" "\0" /* DHCP_MTU */
110 "broadcast" "\0" /* DHCP_BROADCAST */
111 "routes" "\0" /* DHCP_ROUTES */
112 "nisdomain" "\0" /* DHCP_NIS_DOMAIN */
113 "nissrv" "\0" /* DHCP_NIS_SERVER */
114 "ntpsrv" "\0" /* DHCP_NTP_SERVER */
115 "wins" "\0" /* DHCP_WINS_SERVER */
116 "lease" "\0" /* DHCP_LEASE_TIME */
117 "serverid" "\0" /* DHCP_SERVER_ID */
118 "message" "\0" /* DHCP_ERR_MESSAGE */
119 "tftp" "\0" /* DHCP_TFTP_SERVER_NAME */
120 "bootfile" "\0" /* DHCP_BOOT_FILE */
121 // "userclass" "\0" /* DHCP_USER_CLASS */
122 #if ENABLE_FEATURE_UDHCP_RFC3397
123 "search" "\0" /* DHCP_DOMAIN_SEARCH */
124 // doesn't work in udhcpd.conf since OPTION_SIP_SERVERS
125 // is not handled yet by "string->option" conversion code:
126 "sipsrv" "\0" /* DHCP_SIP_SERVERS */
128 "staticroutes" "\0"/* DHCP_STATIC_ROUTES */
129 #if ENABLE_FEATURE_UDHCP_8021Q
130 "vlanid" "\0" /* DHCP_VLAN_ID */
131 "vlanpriority" "\0"/* DHCP_VLAN_PRIORITY */
133 "pxeconffile" "\0" /* DHCP_PXE_CONF_FILE */
134 "pxepathprefix" "\0" /* DHCP_PXE_PATH_PREFIX */
135 "ip6rd" "\0" /* DHCP_6RD */
136 "msstaticroutes""\0"/* DHCP_MS_STATIC_ROUTES */
137 "wpad" "\0" /* DHCP_WPAD */
140 /* Lengths of the option types in binary form.
142 * udhcp_str2optset: to determine how many bytes to allocate.
143 * xmalloc_optname_optval: to estimate string length
144 * from binary option length: (option[LEN] / dhcp_option_lengths[opt_type])
145 * is the number of elements, multiply it by one element's string width
146 * (len_of_option_as_string[opt_type]) and you know how wide string you need.
148 const uint8_t dhcp_option_lengths[] ALIGN1 = {
150 [OPTION_IP_PAIR] = 8,
151 // [OPTION_BOOLEAN] = 1,
152 [OPTION_STRING] = 1, /* ignored by udhcp_str2optset */
153 [OPTION_STRING_HOST] = 1, /* ignored by udhcp_str2optset */
154 #if ENABLE_FEATURE_UDHCP_RFC3397
155 [OPTION_DNS_STRING] = 1, /* ignored by both udhcp_str2optset and xmalloc_optname_optval */
156 [OPTION_SIP_SERVERS] = 1,
163 /* Just like OPTION_STRING, we use minimum length here */
164 [OPTION_STATIC_ROUTES] = 5,
165 [OPTION_6RD] = 12, /* ignored by udhcp_str2optset */
166 /* The above value was chosen as follows:
167 * len_of_option_as_string[] for this option is >60: it's a string of the form
168 * "32 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 ".
169 * Each additional ipv4 address takes 4 bytes in binary option and appends
170 * another "255.255.255.255 " 16-byte string. We can set [OPTION_6RD] = 4
171 * but this severely overestimates string length: instead of 16 bytes,
172 * it adds >60 for every 4 bytes in binary option.
173 * We cheat and declare here that option is in units of 12 bytes.
174 * This adds more than 60 bytes for every three ipv4 addresses - more than enough.
175 * (Even 16 instead of 12 should work, but let's be paranoid).
180 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
181 static void log_option(const char *pfx, const uint8_t *opt)
183 if (dhcp_verbose >= 2) {
184 char buf[256 * 2 + 2];
185 *bin2hex(buf, (void*) (opt + OPT_DATA), opt[OPT_LEN]) = '\0';
186 bb_error_msg("%s: 0x%02x %s", pfx, opt[OPT_CODE], buf);
190 # define log_option(pfx, opt) ((void)0)
193 unsigned FAST_FUNC udhcp_option_idx(const char *name)
195 int n = index_in_strings(dhcp_option_strings, name);
200 char buf[sizeof(dhcp_option_strings)];
202 const char *s = dhcp_option_strings;
203 while (s < dhcp_option_strings + sizeof(dhcp_option_strings) - 2) {
204 *d++ = (*s == '\0' ? ' ' : *s);
208 bb_error_msg_and_die("unknown option '%s', known options: %s", name, buf);
212 /* Get an option with bounds checking (warning, result is not aligned) */
213 uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code)
220 FILE_FIELD101 = FILE_FIELD * 0x101,
221 SNAME_FIELD101 = SNAME_FIELD * 0x101,
224 /* option bytes: [code][len][data1][data2]..[dataLEN] */
225 optionptr = packet->options;
226 rem = sizeof(packet->options);
230 bb_error_msg("bad packet, malformed option field");
234 /* DHCP_PADDING and DHCP_END have no [len] byte */
235 if (optionptr[OPT_CODE] == DHCP_PADDING) {
240 if (optionptr[OPT_CODE] == DHCP_END) {
241 if ((overload & FILE_FIELD101) == FILE_FIELD) {
242 /* can use packet->file, and didn't look at it yet */
243 overload |= FILE_FIELD101; /* "we looked at it" */
244 optionptr = packet->file;
245 rem = sizeof(packet->file);
248 if ((overload & SNAME_FIELD101) == SNAME_FIELD) {
249 /* can use packet->sname, and didn't look at it yet */
250 overload |= SNAME_FIELD101; /* "we looked at it" */
251 optionptr = packet->sname;
252 rem = sizeof(packet->sname);
259 goto complain; /* complain and return NULL */
260 len = 2 + optionptr[OPT_LEN];
263 goto complain; /* complain and return NULL */
265 if (optionptr[OPT_CODE] == code) {
266 log_option("option found", optionptr);
267 return optionptr + OPT_DATA;
270 if (optionptr[OPT_CODE] == DHCP_OPTION_OVERLOAD) {
272 overload |= optionptr[OPT_DATA];
278 /* log3 because udhcpc uses it a lot - very noisy */
279 log3("option 0x%02x not found", code);
283 /* Return the position of the 'end' option (no bounds checking) */
284 int FAST_FUNC udhcp_end_option(uint8_t *optionptr)
288 while (optionptr[i] != DHCP_END) {
289 if (optionptr[i] != DHCP_PADDING)
290 i += optionptr[i + OPT_LEN] + OPT_DATA-1;
296 /* Add an option (supplied in binary form) to the options.
297 * Option format: [code][len][data1][data2]..[dataLEN]
299 void FAST_FUNC udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt)
302 uint8_t *optionptr = packet->options;
303 unsigned end = udhcp_end_option(optionptr);
305 len = OPT_DATA + addopt[OPT_LEN];
306 /* end position + (option code/length + addopt length) + end option */
307 if (end + len + 1 >= DHCP_OPTIONS_BUFSIZE) {
308 //TODO: learn how to use overflow option if we exhaust packet->options[]
309 bb_error_msg("option 0x%02x did not fit into the packet",
313 log_option("adding option", addopt);
314 memcpy(optionptr + end, addopt, len);
315 optionptr[end + len] = DHCP_END;
318 /* Add an one to four byte option to a packet */
319 void FAST_FUNC udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data)
321 const struct dhcp_optflag *dh;
323 for (dh = dhcp_optflags; dh->code; dh++) {
324 if (dh->code == code) {
325 uint8_t option[6], len;
327 option[OPT_CODE] = code;
328 len = dhcp_option_lengths[dh->flags & OPTION_TYPE_MASK];
329 option[OPT_LEN] = len;
331 data <<= 8 * (4 - len);
332 /* Assignment is unaligned! */
333 move_to_unaligned32(&option[OPT_DATA], data);
334 udhcp_add_binary_option(packet, option);
339 bb_error_msg("can't add option 0x%02x", code);
342 /* Find option 'code' in opt_list */
343 struct option_set* FAST_FUNC udhcp_find_option(struct option_set *opt_list, uint8_t code)
345 while (opt_list && opt_list->data[OPT_CODE] < code)
346 opt_list = opt_list->next;
348 if (opt_list && opt_list->data[OPT_CODE] == code)
353 /* Parse string to IP in network order */
354 int FAST_FUNC udhcp_str2nip(const char *str, void *arg)
356 len_and_sockaddr *lsa;
358 lsa = host_and_af2sockaddr(str, 0, AF_INET);
361 /* arg maybe unaligned */
362 move_to_unaligned32((uint32_t*)arg, lsa->u.sin.sin_addr.s_addr);
368 * Parse string option representation to binary form and add it to opt_list.
369 * Called to parse "udhcpc -x OPTNAME:OPTVAL"
370 * and to parse udhcpd.conf's "opt OPTNAME OPTVAL" directives.
372 /* helper for the helper */
373 static char *allocate_tempopt_if_needed(
374 const struct dhcp_optflag *optflag,
378 char *allocated = NULL;
379 if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_BIN) {
381 allocated = xstrdup(buffer); /* more than enough */
382 end = hex2bin(allocated, buffer, 255);
384 bb_error_msg_and_die("malformed hex string '%s'", buffer);
385 *length_p = end - allocated;
389 /* helper: add an option to the opt_list */
390 static NOINLINE void attach_option(
391 struct option_set **opt_list,
392 const struct dhcp_optflag *optflag,
396 struct option_set *existing;
399 allocated = allocate_tempopt_if_needed(optflag, buffer, &length);
400 #if ENABLE_FEATURE_UDHCP_RFC3397
401 if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_DNS_STRING) {
402 /* reuse buffer and length for RFC1035-formatted string */
403 allocated = buffer = (char *)dname_enc(NULL, 0, buffer, &length);
407 existing = udhcp_find_option(*opt_list, optflag->code);
409 struct option_set *new, **curr;
411 /* make a new option */
412 log2("attaching option %02x to list", optflag->code);
413 new = xmalloc(sizeof(*new));
414 new->data = xmalloc(length + OPT_DATA);
415 new->data[OPT_CODE] = optflag->code;
416 new->data[OPT_LEN] = length;
417 memcpy(new->data + OPT_DATA, (allocated ? allocated : buffer), length);
420 while (*curr && (*curr)->data[OPT_CODE] < optflag->code)
421 curr = &(*curr)->next;
428 if (optflag->flags & OPTION_LIST) {
431 /* add it to an existing option */
432 log2("attaching option %02x to existing member of list", optflag->code);
433 old_len = existing->data[OPT_LEN];
434 if (old_len + length < 255) {
435 /* actually 255 is ok too, but adding a space can overlow it */
437 existing->data = xrealloc(existing->data, OPT_DATA + 1 + old_len + length);
438 if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_STRING
439 || (optflag->flags & OPTION_TYPE_MASK) == OPTION_STRING_HOST
441 /* add space separator between STRING options in a list */
442 existing->data[OPT_DATA + old_len] = ' ';
445 memcpy(existing->data + OPT_DATA + old_len, (allocated ? allocated : buffer), length);
446 existing->data[OPT_LEN] = old_len + length;
447 } /* else, ignore the data, we could put this in a second option in the future */
448 } /* else, ignore the new data */
454 int FAST_FUNC udhcp_str2optset(const char *const_str, void *arg)
456 struct option_set **opt_list = arg;
459 const struct dhcp_optflag *optflag;
460 struct dhcp_optflag bin_optflag;
463 /* IP_PAIR needs 8 bytes, STATIC_ROUTES needs 9 max */
464 char buffer[9] ALIGNED(4);
465 uint16_t *result_u16 = (uint16_t *) buffer;
466 uint32_t *result_u32 = (uint32_t *) buffer;
468 /* Cheat, the only *const* str possible is "" */
469 str = (char *) const_str;
470 opt = strtok(str, " \t=");
474 optcode = bb_strtou(opt, NULL, 0);
475 if (!errno && optcode < 255) {
476 /* Raw (numeric) option code */
477 bin_optflag.flags = OPTION_BIN;
478 bin_optflag.code = optcode;
479 optflag = &bin_optflag;
481 optflag = &dhcp_optflags[udhcp_option_idx(opt)];
486 val = strtok(NULL, ", \t");
489 length = dhcp_option_lengths[optflag->flags & OPTION_TYPE_MASK];
491 opt = buffer; /* new meaning for variable opt */
492 switch (optflag->flags & OPTION_TYPE_MASK) {
494 retval = udhcp_str2nip(val, buffer);
497 retval = udhcp_str2nip(val, buffer);
498 val = strtok(NULL, ", \t/-");
502 retval = udhcp_str2nip(val, buffer + 4);
505 case OPTION_STRING_HOST:
506 #if ENABLE_FEATURE_UDHCP_RFC3397
507 case OPTION_DNS_STRING:
509 length = strnlen(val, 254);
515 // case OPTION_BOOLEAN: {
516 // static const char no_yes[] ALIGN1 = "no\0yes\0";
517 // buffer[0] = retval = index_in_strings(no_yes, val);
518 // retval++; /* 0 - bad; 1: "no" 2: "yes" */
522 buffer[0] = bb_strtou32(val, NULL, 0);
523 retval = (errno == 0);
525 /* htonX are macros in older libc's, using temp var
526 * in code below for safety */
527 /* TODO: use bb_strtoX? */
529 uint32_t tmp = bb_strtou32(val, NULL, 0);
530 *result_u16 = htons(tmp);
531 retval = (errno == 0 /*&& tmp < 0x10000*/);
534 // case OPTION_S16: {
535 // long tmp = bb_strtoi32(val, NULL, 0);
536 // *result_u16 = htons(tmp);
537 // retval = (errno == 0);
541 uint32_t tmp = bb_strtou32(val, NULL, 0);
542 *result_u32 = htonl(tmp);
543 retval = (errno == 0);
547 int32_t tmp = bb_strtoi32(val, NULL, 0);
548 *result_u32 = htonl(tmp);
549 retval = (errno == 0);
552 case OPTION_STATIC_ROUTES: {
553 /* Input: "a.b.c.d/m" */
554 /* Output: mask(1 byte),pfx(0-4 bytes),gw(4 bytes) */
556 char *slash = strchr(val, '/');
559 retval = udhcp_str2nip(val, buffer + 1);
560 buffer[0] = mask = bb_strtou(slash + 1, NULL, 10);
561 val = strtok(NULL, ", \t/-");
562 if (!val || mask > 32 || errno)
565 length = ((mask + 7) >> 3) + 5;
566 retval = udhcp_str2nip(val, buffer + (length - 4));
571 case OPTION_BIN: /* handled in attach_option() */
578 attach_option(opt_list, optflag, opt, length);
579 } while (retval && (optflag->flags & OPTION_LIST));
584 /* note: ip is a pointer to an IPv6 in network order, possibly misaliged */
585 int FAST_FUNC sprint_nip6(char *dest, /*const char *pre,*/ const uint8_t *ip)
587 char hexstrbuf[16 * 2];
588 bin2hex(hexstrbuf, (void*)ip, 16);
589 return sprintf(dest, /* "%s" */
590 "%.4s:%.4s:%.4s:%.4s:%.4s:%.4s:%.4s:%.4s",