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busybox: update to 1.25.0
[tomato.git] / release / src / router / busybox / networking / udhcp / dhcpc.c
blob1e673720c9268069befef44429fa35197d3a3078
1 /* vi: set sw=4 ts=4: */
2 /*
3 * udhcp client
4 *
5 * Russ Dill <Russ.Dill@asu.edu> July 2001
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21 #include <syslog.h>
22 /* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
23 #define WANT_PIDFILE 1
24 #include "common.h"
25 #include "dhcpd.h"
26 #include "dhcpc.h"
27
28 #include <asm/types.h>
29 /*#if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined(_NEWLIB_VERSION)
30 # include <linux/if_packet.h>
31 # include <netinet/if_ether.h>
32 #else */
33 # include <linux/if_packet.h>
34 # include <linux/if_ether.h>
35 /*#endif*/
36 #include <linux/filter.h>
37
38 #ifndef PACKET_AUXDATA
39 # define PACKET_AUXDATA 8
40 struct tpacket_auxdata {
41 uint32_t tp_status;
42 uint32_t tp_len;
43 uint32_t tp_snaplen;
44 uint16_t tp_mac;
45 uint16_t tp_net;
46 uint16_t tp_vlan_tci;
47 uint16_t tp_padding;
48 };
49 #endif
50
51
52 /* "struct client_config_t client_config" is in bb_common_bufsiz1 */
53
54
55 #if ENABLE_LONG_OPTS
56 static const char udhcpc_longopts[] ALIGN1 =
57 "clientid-none\0" No_argument "C"
58 "vendorclass\0" Required_argument "V"
59 "hostname\0" Required_argument "H"
60 "fqdn\0" Required_argument "F"
61 "interface\0" Required_argument "i"
62 "now\0" No_argument "n"
63 "pidfile\0" Required_argument "p"
64 "quit\0" No_argument "q"
65 "release\0" No_argument "R"
66 "request\0" Required_argument "r"
67 "script\0" Required_argument "s"
68 "timeout\0" Required_argument "T"
69 "version\0" No_argument "v"
70 "retries\0" Required_argument "t"
71 "tryagain\0" Required_argument "A"
72 "syslog\0" No_argument "S"
73 "request-option\0" Required_argument "O"
74 "no-default-options\0" No_argument "o"
75 "foreground\0" No_argument "f"
76 "background\0" No_argument "b"
77 "broadcast\0" No_argument "B"
78 IF_FEATURE_UDHCPC_ARPING("arping\0" Optional_argument "a")
79 IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
80 ;
81 #endif
82 /* Must match getopt32 option string order */
83 enum {
84 OPT_C = 1 << 0,
85 OPT_V = 1 << 1,
86 OPT_H = 1 << 2,
87 OPT_h = 1 << 3,
88 OPT_F = 1 << 4,
89 OPT_i = 1 << 5,
90 OPT_n = 1 << 6,
91 OPT_p = 1 << 7,
92 OPT_q = 1 << 8,
93 OPT_R = 1 << 9,
94 OPT_r = 1 << 10,
95 OPT_s = 1 << 11,
96 OPT_T = 1 << 12,
97 OPT_t = 1 << 13,
98 OPT_S = 1 << 14,
99 OPT_A = 1 << 15,
100 OPT_O = 1 << 16,
101 OPT_o = 1 << 17,
102 OPT_x = 1 << 18,
103 OPT_f = 1 << 19,
104 OPT_B = 1 << 20,
105 OPT_m = 1 << 21, // zzz
106 /* The rest has variable bit positions, need to be clever */
107 OPTBIT_LAST = 21,
108 USE_FOR_MMU( OPTBIT_b,)
109 IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
110 IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
111 USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
112 IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
113 IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
114 };
115
116
117 /*** Script execution code ***/
118
119 /* get a rough idea of how long an option will be (rounding up...) */
120 static const uint8_t len_of_option_as_string[] ALIGN1 = {
121 [OPTION_IP ] = sizeof("255.255.255.255 "),
122 [OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2,
123 [OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "),
124 [OPTION_6RD ] = sizeof("132 128 FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 255.255.255.255 "),
125 [OPTION_STRING ] = 1,
126 [OPTION_STRING_HOST ] = 1,
127 #if ENABLE_FEATURE_UDHCP_RFC3397
128 [OPTION_DNS_STRING ] = 1, /* unused */
129 /* Hmmm, this severely overestimates size if SIP_SERVERS option
130 * is in domain name form: N-byte option in binary form
131 * mallocs ~16*N bytes. But it is freed almost at once.
132 */
133 [OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "),
134 #endif
135 // [OPTION_BOOLEAN ] = sizeof("yes "),
136 [OPTION_U8 ] = sizeof("255 "),
137 [OPTION_U16 ] = sizeof("65535 "),
138 // [OPTION_S16 ] = sizeof("-32768 "),
139 [OPTION_U32 ] = sizeof("4294967295 "),
140 [OPTION_S32 ] = sizeof("-2147483684 "),
141 };
142
143 /* note: ip is a pointer to an IP in network order, possibly misaliged */
144 static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
145 {
146 return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
147 }
148
149 /* really simple implementation, just count the bits */
150 static int mton(uint32_t mask)
151 {
152 int i = 0;
153 mask = ntohl(mask); /* 111110000-like bit pattern */
154 while (mask) {
155 i++;
156 mask <<= 1;
157 }
158 return i;
159 }
160
161 #if ENABLE_FEATURE_UDHCPC_SANITIZEOPT
162 /* Check if a given label represents a valid DNS label
163 * Return pointer to the first character after the label upon success,
164 * NULL otherwise.
165 * See RFC1035, 2.3.1
166 */
167 /* We don't need to be particularly anal. For example, allowing _, hyphen
168 * at the end, or leading and trailing dots would be ok, since it
169 * can't be used for attacks. (Leading hyphen can be, if someone uses
170 * cmd "$hostname"
171 * in the script: then hostname may be treated as an option)
172 */
173 static const char *valid_domain_label(const char *label)
174 {
175 unsigned char ch;
176 unsigned pos = 0;
177
178 for (;;) {
179 ch = *label;
180 if ((ch|0x20) < 'a' || (ch|0x20) > 'z') {
181 if (ch < '0' || ch > '9') {
182 if (ch == '\0' || ch == '.')
183 return label;
184 /* DNS allows only '-', but we are more permissive */
185 if (ch != '-' && ch != '_')
186 return NULL;
187 }
188 }
189 label++;
190 pos++;
191 //Do we want this?
192 //if (pos > 63) /* NS_MAXLABEL; labels must be 63 chars or less */
193 // return NULL;
194 }
195 }
196
197 /* Check if a given name represents a valid DNS name */
198 /* See RFC1035, 2.3.1 */
199 static int good_hostname(const char *name)
200 {
201 //const char *start = name;
202
203 for (;;) {
204 name = valid_domain_label(name);
205 if (!name)
206 return 0;
207 if (!name[0])
208 return 1;
209 //Do we want this?
210 //return ((name - start) < 1025); /* NS_MAXDNAME */
211 name++;
212 if (*name == '\0')
213 return 1; // We allow trailing dot too
214 }
215 }
216 #else
217 # define good_hostname(name) 1
218 #endif
219
220 /* Create "opt_name=opt_value" string */
221 static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name)
222 {
223 unsigned upper_length;
224 int len, type, optlen;
225 char *dest, *ret;
226
227 /* option points to OPT_DATA, need to go back to get OPT_LEN */
228 len = option[-OPT_DATA + OPT_LEN];
229
230 type = optflag->flags & OPTION_TYPE_MASK;
231 optlen = dhcp_option_lengths[type];
232 upper_length = len_of_option_as_string[type]
233 * ((unsigned)(len + optlen) / (unsigned)optlen);
234
235 dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
236 dest += sprintf(ret, "%s=", opt_name);
237
238 while (len >= optlen) {
239 switch (type) {
240 case OPTION_IP:
241 case OPTION_IP_PAIR:
242 dest += sprint_nip(dest, "", option);
243 if (type == OPTION_IP)
244 break;
245 dest += sprint_nip(dest, "/", option + 4);
246 break;
247 // case OPTION_BOOLEAN:
248 // dest += sprintf(dest, *option ? "yes" : "no");
249 // break;
250 case OPTION_U8:
251 dest += sprintf(dest, "%u", *option);
252 break;
253 // case OPTION_S16:
254 case OPTION_U16: {
255 uint16_t val_u16;
256 move_from_unaligned16(val_u16, option);
257 dest += sprintf(dest, "%u", ntohs(val_u16));
258 break;
259 }
260 case OPTION_S32:
261 case OPTION_U32: {
262 uint32_t val_u32;
263 move_from_unaligned32(val_u32, option);
264 dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
265 break;
266 }
267 /* Note: options which use 'return' instead of 'break'
268 * (for example, OPTION_STRING) skip the code which handles
269 * the case of list of options.
270 */
271 case OPTION_STRING:
272 case OPTION_STRING_HOST:
273 memcpy(dest, option, len);
274 dest[len] = '\0';
275 if (type == OPTION_STRING_HOST && !good_hostname(dest))
276 safe_strncpy(dest, "bad", len);
277 return ret;
278 case OPTION_STATIC_ROUTES: {
279 /* Option binary format:
280 * mask [one byte, 0..32]
281 * ip [big endian, 0..4 bytes depending on mask]
282 * router [big endian, 4 bytes]
283 * may be repeated
284 *
285 * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
286 */
287 const char *pfx = "";
288
289 while (len >= 1 + 4) { /* mask + 0-byte ip + router */
290 uint32_t nip;
291 uint8_t *p;
292 unsigned mask;
293 int bytes;
294
295 mask = *option++;
296 if (mask > 32)
297 break;
298 len--;
299
300 nip = 0;
301 p = (void*) &nip;
302 bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
303 while (--bytes >= 0) {
304 *p++ = *option++;
305 len--;
306 }
307 if (len < 4)
308 break;
309
310 /* print ip/mask */
311 dest += sprint_nip(dest, pfx, (void*) &nip);
312 pfx = " ";
313 dest += sprintf(dest, "/%u ", mask);
314 /* print router */
315 dest += sprint_nip(dest, "", option);
316 option += 4;
317 len -= 4;
318 }
319
320 return ret;
321 }
322 case OPTION_6RD:
323 /* Option binary format (see RFC 5969):
324 * 0 1 2 3
325 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
326 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
327 * | OPTION_6RD | option-length | IPv4MaskLen | 6rdPrefixLen |
328 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
329 * | 6rdPrefix |
330 * ... (16 octets) ...
331 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
332 * ... 6rdBRIPv4Address(es) ...
333 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
334 * We convert it to a string
335 * "IPv4MaskLen 6rdPrefixLen 6rdPrefix 6rdBRIPv4Address..."
336 *
337 * Sanity check: ensure that our length is at least 22 bytes, that
338 * IPv4MaskLen <= 32,
339 * 6rdPrefixLen <= 128,
340 * 6rdPrefixLen + (32 - IPv4MaskLen) <= 128
341 * (2nd condition need no check - it follows from 1st and 3rd).
342 * Else, return envvar with empty value ("optname=")
343 */
344 if (len >= (1 + 1 + 16 + 4)
345 && option[0] <= 32
346 && (option[1] + 32 - option[0]) <= 128
347 ) {
348 /* IPv4MaskLen */
349 dest += sprintf(dest, "%u ", *option++);
350 /* 6rdPrefixLen */
351 dest += sprintf(dest, "%u ", *option++);
352 /* 6rdPrefix */
353 dest += sprint_nip6(dest, /* "", */ option);
354 option += 16;
355 len -= 1 + 1 + 16 + 4;
356 /* "+ 4" above corresponds to the length of IPv4 addr
357 * we consume in the loop below */
358 while (1) {
359 /* 6rdBRIPv4Address(es) */
360 dest += sprint_nip(dest, " ", option);
361 option += 4;
362 len -= 4; /* do we have yet another 4+ bytes? */
363 if (len < 0)
364 break; /* no */
365 }
366 }
367
368 return ret;
369 #if ENABLE_FEATURE_UDHCP_RFC3397
370 case OPTION_DNS_STRING:
371 /* unpack option into dest; use ret for prefix (i.e., "optname=") */
372 dest = dname_dec(option, len, ret);
373 if (dest) {
374 free(ret);
375 return dest;
376 }
377 /* error. return "optname=" string */
378 return ret;
379 case OPTION_SIP_SERVERS:
380 /* Option binary format:
381 * type: byte
382 * type=0: domain names, dns-compressed
383 * type=1: IP addrs
384 */
385 option++;
386 len--;
387 if (option[-1] == 0) {
388 dest = dname_dec(option, len, ret);
389 if (dest) {
390 free(ret);
391 return dest;
392 }
393 } else
394 if (option[-1] == 1) {
395 const char *pfx = "";
396 while (1) {
397 len -= 4;
398 if (len < 0)
399 break;
400 dest += sprint_nip(dest, pfx, option);
401 pfx = " ";
402 option += 4;
403 }
404 }
405 return ret;
406 #endif
407 } /* switch */
408
409 /* If we are here, try to format any remaining data
410 * in the option as another, similarly-formatted option
411 */
412 option += optlen;
413 len -= optlen;
414 // TODO: it can be a list only if (optflag->flags & OPTION_LIST).
415 // Should we bail out/warn if we see multi-ip option which is
416 // not allowed to be such (for example, DHCP_BROADCAST)? -
417 if (len < optlen /* || !(optflag->flags & OPTION_LIST) */)
418 break;
419 *dest++ = ' ';
420 *dest = '\0';
421 } /* while */
422
423 return ret;
424 }
425
426 /* put all the parameters into the environment */
427 static char **fill_envp(struct dhcp_packet *packet)
428 {
429 int envc;
430 int i;
431 char **envp, **curr;
432 const char *opt_name;
433 uint8_t *temp;
434 uint8_t overload = 0;
435
436 #define BITMAP unsigned
437 #define BBITS (sizeof(BITMAP) * 8)
438 #define BMASK(i) (1 << (i & (sizeof(BITMAP) * 8 - 1)))
439 #define FOUND_OPTS(i) (found_opts[(unsigned)i / BBITS])
440 BITMAP found_opts[256 / BBITS];
441
442 memset(found_opts, 0, sizeof(found_opts));
443
444 /* We need 6 elements for:
445 * "interface=IFACE"
446 * "ip=N.N.N.N" from packet->yiaddr
447 * "siaddr=IP" from packet->siaddr_nip (unless 0)
448 * "boot_file=FILE" from packet->file (unless overloaded)
449 * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded)
450 * terminating NULL
451 */
452 envc = 6;
453 /* +1 element for each option, +2 for subnet option: */
454 if (packet) {
455 /* note: do not search for "pad" (0) and "end" (255) options */
456 //TODO: change logic to scan packet _once_
457 for (i = 1; i < 255; i++) {
458 temp = udhcp_get_option(packet, i);
459 if (temp) {
460 if (i == DHCP_OPTION_OVERLOAD)
461 overload = *temp;
462 else if (i == DHCP_SUBNET)
463 envc++; /* for $mask */
464 envc++;
465 /*if (i != DHCP_MESSAGE_TYPE)*/
466 FOUND_OPTS(i) |= BMASK(i);
467 }
468 }
469 }
470 curr = envp = xzalloc(sizeof(envp[0]) * envc);
471
472 *curr = xasprintf("interface=%s", client_config.interface);
473 putenv(*curr++);
474
475 if (!packet)
476 return envp;
477
478 /* Export BOOTP fields. Fields we don't (yet?) export:
479 * uint8_t op; // always BOOTREPLY
480 * uint8_t htype; // hardware address type. 1 = 10mb ethernet
481 * uint8_t hlen; // hardware address length
482 * uint8_t hops; // used by relay agents only
483 * uint32_t xid;
484 * uint16_t secs; // elapsed since client began acquisition/renewal
485 * uint16_t flags; // only one flag so far: bcast. Never set by server
486 * uint32_t ciaddr; // client IP (usually == yiaddr. can it be different
487 * // if during renew server wants to give us differn IP?)
488 * uint32_t gateway_nip; // relay agent IP address
489 * uint8_t chaddr[16]; // link-layer client hardware address (MAC)
490 * TODO: export gateway_nip as $giaddr?
491 */
492 /* Most important one: yiaddr as $ip */
493 *curr = xmalloc(sizeof("ip=255.255.255.255"));
494 sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
495 putenv(*curr++);
496 if (packet->siaddr_nip) {
497 /* IP address of next server to use in bootstrap */
498 *curr = xmalloc(sizeof("siaddr=255.255.255.255"));
499 sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
500 putenv(*curr++);
501 }
502 if (!(overload & FILE_FIELD) && packet->file[0]) {
503 /* watch out for invalid packets */
504 *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
505 putenv(*curr++);
506 }
507 if (!(overload & SNAME_FIELD) && packet->sname[0]) {
508 /* watch out for invalid packets */
509 *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
510 putenv(*curr++);
511 }
512
513 /* Export known DHCP options */
514 opt_name = dhcp_option_strings;
515 i = 0;
516 while (*opt_name) {
517 uint8_t code = dhcp_optflags[i].code;
518 BITMAP *found_ptr = &FOUND_OPTS(code);
519 BITMAP found_mask = BMASK(code);
520 if (!(*found_ptr & found_mask))
521 goto next;
522 *found_ptr &= ~found_mask; /* leave only unknown options */
523 temp = udhcp_get_option(packet, code);
524 *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name);
525 putenv(*curr++);
526 if (code == DHCP_SUBNET) {
527 /* Subnet option: make things like "$ip/$mask" possible */
528 uint32_t subnet;
529 move_from_unaligned32(subnet, temp);
530 *curr = xasprintf("mask=%u", mton(subnet));
531 putenv(*curr++);
532 }
533 next:
534 opt_name += strlen(opt_name) + 1;
535 i++;
536 }
537 /* Export unknown options */
538 for (i = 0; i < 256;) {
539 BITMAP bitmap = FOUND_OPTS(i);
540 if (!bitmap) {
541 i += BBITS;
542 continue;
543 }
544 if (bitmap & BMASK(i)) {
545 unsigned len, ofs;
546
547 temp = udhcp_get_option(packet, i);
548 /* udhcp_get_option returns ptr to data portion,
549 * need to go back to get len
550 */
551 len = temp[-OPT_DATA + OPT_LEN];
552 *curr = xmalloc(sizeof("optNNN=") + 1 + len*2);
553 ofs = sprintf(*curr, "opt%u=", i);
554 *bin2hex(*curr + ofs, (void*) temp, len) = '\0';
555 putenv(*curr++);
556 }
557 i++;
558 }
559
560 return envp;
561 }
562
563 /* Call a script with a par file and env vars */
564 static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
565 {
566 char **envp, **curr;
567 char *argv[3];
568
569 envp = fill_envp(packet);
570
571 /* call script */
572 log1("executing %s %s", client_config.script, name);
573 argv[0] = (char*) client_config.script;
574 argv[1] = (char*) name;
575 argv[2] = NULL;
576 spawn_and_wait(argv);
577
578 for (curr = envp; *curr; curr++) {
579 log2(" %s", *curr);
580 bb_unsetenv_and_free(*curr);
581 }
582 free(envp);
583 }
584
585
586 /*** Sending/receiving packets ***/
587
588 static ALWAYS_INLINE uint32_t random_xid(void)
589 {
590 return rand();
591 }
592
593 /* Initialize the packet with the proper defaults */
594 static void init_packet(struct dhcp_packet *packet, char type)
595 {
596 uint16_t secs;
597
598 /* Fill in: op, htype, hlen, cookie fields; message type option: */
599 udhcp_init_header(packet, type);
600
601 packet->xid = random_xid();
602
603 client_config.last_secs = monotonic_sec();
604 if (client_config.first_secs == 0)
605 client_config.first_secs = client_config.last_secs;
606 secs = client_config.last_secs - client_config.first_secs;
607 packet->secs = htons(secs);
608
609 memcpy(packet->chaddr, client_config.client_mac, 6);
610 if (client_config.clientid)
611 udhcp_add_binary_option(packet, client_config.clientid);
612 }
613
614 static void add_client_options(struct dhcp_packet *packet)
615 {
616 int i, end, len;
617
618 len = sizeof(struct ip_udp_dhcp_packet);
619 if (client_config.client_mtu == 0 ||
620 client_config.client_mtu > len)
621 udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(len));
622
623 /* Add a "param req" option with the list of options we'd like to have
624 * from stubborn DHCP servers. Pull the data from the struct in common.c.
625 * No bounds checking because it goes towards the head of the packet. */
626 end = udhcp_end_option(packet->options);
627 len = 0;
628 for (i = 1; i < DHCP_END; i++) {
629 if (client_config.opt_mask[i >> 3] & (1 << (i & 7))) {
630 packet->options[end + OPT_DATA + len] = i;
631 len++;
632 }
633 }
634 if (len) {
635 packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
636 packet->options[end + OPT_LEN] = len;
637 packet->options[end + OPT_DATA + len] = DHCP_END;
638 }
639
640 if (client_config.vendorclass)
641 udhcp_add_binary_option(packet, client_config.vendorclass);
642 if (client_config.hostname)
643 udhcp_add_binary_option(packet, client_config.hostname);
644 if (client_config.fqdn)
645 udhcp_add_binary_option(packet, client_config.fqdn);
646
647 /* Request broadcast replies if we have no IP addr */
648 if ((option_mask32 & OPT_B) && packet->ciaddr == 0)
649 packet->flags |= htons(BROADCAST_FLAG);
650
651 /* Request broadcast replies if we have no IP addr */
652 if ((option_mask32 & OPT_B) && packet->ciaddr == 0)
653 packet->flags |= htons(BROADCAST_FLAG);
654
655 /* Add -x options if any */
656 {
657 struct option_set *curr = client_config.options;
658 while (curr) {
659 udhcp_add_binary_option(packet, curr->data);
660 curr = curr->next;
661 }
662 // if (client_config.sname)
663 // strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
664 // if (client_config.boot_file)
665 // strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
666 }
667
668 // This will be needed if we remove -V VENDOR_STR in favor of
669 // -x vendor:VENDOR_STR
670 //if (!udhcp_find_option(packet.options, DHCP_VENDOR))
671 // /* not set, set the default vendor ID */
672 // ...add (DHCP_VENDOR, "udhcp "BB_VER) opt...
673 }
674
675 /* RFC 2131
676 * 4.4.4 Use of broadcast and unicast
677 *
678 * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
679 * messages, unless the client knows the address of a DHCP server.
680 * The client unicasts DHCPRELEASE messages to the server. Because
681 * the client is declining the use of the IP address supplied by the server,
682 * the client broadcasts DHCPDECLINE messages.
683 *
684 * When the DHCP client knows the address of a DHCP server, in either
685 * INIT or REBOOTING state, the client may use that address
686 * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
687 * The client may also use unicast to send DHCPINFORM messages
688 * to a known DHCP server. If the client receives no response to DHCP
689 * messages sent to the IP address of a known DHCP server, the DHCP
690 * client reverts to using the IP broadcast address.
691 */
692
693 static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet, uint32_t src_nip)
694 {
695 return udhcp_send_raw_packet(packet,
696 /*src*/ src_nip, CLIENT_PORT,
697 /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
698 client_config.ifindex);
699 }
700
701 static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t server)
702 {
703 if (server)
704 return udhcp_send_kernel_packet(packet,
705 ciaddr, CLIENT_PORT,
706 server, SERVER_PORT);
707 return raw_bcast_from_client_config_ifindex(packet, ciaddr);
708 }
709
710 /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
711 /* NOINLINE: limit stack usage in caller */
712 static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
713 {
714 struct dhcp_packet packet;
715 static int msgs = 0;
716
717 /* Fill in: op, htype, hlen, cookie, chaddr fields,
718 * random xid field (we override it below),
719 * client-id option (unless -C), message type option:
720 */
721 init_packet(&packet, DHCPDISCOVER);
722
723 packet.xid = xid;
724 if (requested)
725 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
726
727 /* Add options: maxsize,
728 * optionally: hostname, fqdn, vendorclass,
729 * "param req" option according to -O, options specified with -x
730 */
731 add_client_options(&packet);
732
733 if (msgs++ < 3)
734 bb_error_msg("sending %s", "discover");
735 return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
736 }
737
738 /* Broadcast a DHCP request message */
739 /* RFC 2131 3.1 paragraph 3:
740 * "The client _broadcasts_ a DHCPREQUEST message..."
741 */
742 /* NOINLINE: limit stack usage in caller */
743 static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
744 {
745 struct dhcp_packet packet;
746 struct in_addr addr;
747
748 /*
749 * RFC 2131 4.3.2 DHCPREQUEST message
750 * ...
751 * If the DHCPREQUEST message contains a 'server identifier'
752 * option, the message is in response to a DHCPOFFER message.
753 * Otherwise, the message is a request to verify or extend an
754 * existing lease. If the client uses a 'client identifier'
755 * in a DHCPREQUEST message, it MUST use that same 'client identifier'
756 * in all subsequent messages. If the client included a list
757 * of requested parameters in a DHCPDISCOVER message, it MUST
758 * include that list in all subsequent messages.
759 */
760 /* Fill in: op, htype, hlen, cookie, chaddr fields,
761 * random xid field (we override it below),
762 * client-id option (unless -C), message type option:
763 */
764 init_packet(&packet, DHCPREQUEST);
765
766 packet.xid = xid;
767 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
768
769 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
770
771 /* Add options: maxsize,
772 * optionally: hostname, fqdn, vendorclass,
773 * "param req" option according to -O, and options specified with -x
774 */
775 add_client_options(&packet);
776
777 addr.s_addr = requested;
778 bb_error_msg("sending select for %s", inet_ntoa(addr));
779 return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
780 }
781
782 /* Unicast or broadcast a DHCP renew message */
783 /* NOINLINE: limit stack usage in caller */
784 static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
785 {
786 struct dhcp_packet packet;
787
788 /*
789 * RFC 2131 4.3.2 DHCPREQUEST message
790 * ...
791 * DHCPREQUEST generated during RENEWING state:
792 *
793 * 'server identifier' MUST NOT be filled in, 'requested IP address'
794 * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
795 * client's IP address. In this situation, the client is completely
796 * configured, and is trying to extend its lease. This message will
797 * be unicast, so no relay agents will be involved in its
798 * transmission. Because 'giaddr' is therefore not filled in, the
799 * DHCP server will trust the value in 'ciaddr', and use it when
800 * replying to the client.
801 */
802 /* Fill in: op, htype, hlen, cookie, chaddr fields,
803 * random xid field (we override it below),
804 * client-id option (unless -C), message type option:
805 */
806 init_packet(&packet, DHCPREQUEST);
807
808 packet.xid = xid;
809 packet.ciaddr = ciaddr;
810
811 /* Add options: maxsize,
812 * optionally: hostname, fqdn, vendorclass,
813 * "param req" option according to -O, and options specified with -x
814 */
815 add_client_options(&packet);
816
817 bb_error_msg("sending %s", "renew");
818 return bcast_or_ucast(&packet, ciaddr, server);
819 }
820
821 #if ENABLE_FEATURE_UDHCPC_ARPING
822 /* Broadcast a DHCP decline message */
823 /* NOINLINE: limit stack usage in caller */
824 static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
825 {
826 struct dhcp_packet packet;
827
828 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
829 * client-id option (unless -C), message type option:
830 */
831 init_packet(&packet, DHCPDECLINE);
832
833 #if 0
834 /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
835 * but in case the server is buggy and wants DHCPDECLINE's xid
836 * to match the xid which started entire handshake,
837 * we use the same xid we used in initial DHCPDISCOVER:
838 */
839 packet.xid = xid;
840 #endif
841 /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
842 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
843
844 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
845
846 bb_error_msg("sending %s", "decline");
847 return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
848 }
849 #endif
850
851 /* Unicast a DHCP release message */
852 static int send_release(uint32_t server, uint32_t ciaddr)
853 {
854 struct dhcp_packet packet;
855
856 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
857 * client-id option (unless -C), message type option:
858 */
859 init_packet(&packet, DHCPRELEASE);
860
861 /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
862 packet.ciaddr = ciaddr;
863
864 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
865
866 bb_error_msg("sending %s", "release");
867 /* Note: normally we unicast here since "server" is not zero.
868 * However, there _are_ people who run "address-less" DHCP servers,
869 * and reportedly ISC dhcp client and Windows allow that.
870 */
871 return bcast_or_ucast(&packet, ciaddr, server);
872 }
873
874 /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
875 /* NOINLINE: limit stack usage in caller */
876 static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
877 {
878 int bytes;
879 struct ip_udp_dhcp_packet packet;
880 uint16_t check;
881 unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
882 struct iovec iov;
883 struct msghdr msg;
884 struct cmsghdr *cmsg;
885
886 /* used to use just safe_read(fd, &packet, sizeof(packet))
887 * but we need to check for TP_STATUS_CSUMNOTREADY :(
888 */
889 iov.iov_base = &packet;
890 iov.iov_len = sizeof(packet);
891 memset(&msg, 0, sizeof(msg));
892 msg.msg_iov = &iov;
893 msg.msg_iovlen = 1;
894 msg.msg_control = cmsgbuf;
895 msg.msg_controllen = sizeof(cmsgbuf);
896 for (;;) {
897 bytes = recvmsg(fd, &msg, 0);
898 if (bytes < 0) {
899 if (errno == EINTR)
900 continue;
901 log1("packet read error, ignoring");
902 /* NB: possible down interface, etc. Caller should pause. */
903 return bytes; /* returns -1 */
904 }
905 break;
906 }
907
908 if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
909 log1("packet is too short, ignoring");
910 return -2;
911 }
912
913 if (bytes < ntohs(packet.ip.tot_len)) {
914 /* packet is bigger than sizeof(packet), we did partial read */
915 log1("oversized packet, ignoring");
916 return -2;
917 }
918
919 /* ignore any extra garbage bytes */
920 bytes = ntohs(packet.ip.tot_len);
921
922 /* make sure its the right packet for us, and that it passes sanity checks */
923 if (packet.ip.protocol != IPPROTO_UDP
924 || packet.ip.version != IPVERSION
925 || packet.ip.ihl != (sizeof(packet.ip) >> 2)
926 || packet.udp.dest != htons(CLIENT_PORT)
927 /* || bytes > (int) sizeof(packet) - can't happen */
928 || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
929 ) {
930 log1("unrelated/bogus packet, ignoring");
931 return -2;
932 }
933
934 /* verify IP checksum */
935 check = packet.ip.check;
936 packet.ip.check = 0;
937 if (check != inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip))) {
938 log1("bad IP header checksum, ignoring");
939 return -2;
940 }
941
942 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
943 if (cmsg->cmsg_level == SOL_PACKET
944 && cmsg->cmsg_type == PACKET_AUXDATA
945 ) {
946 /* some VMs don't checksum UDP and TCP data
947 * they send to the same physical machine,
948 * here we detect this case:
949 */
950 struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
951 if (aux->tp_status & TP_STATUS_CSUMNOTREADY)
952 goto skip_udp_sum_check;
953 }
954 }
955
956 /* verify UDP checksum. IP header has to be modified for this */
957 memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
958 /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
959 packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
960 check = packet.udp.check;
961 packet.udp.check = 0;
962 if (check && check != inet_cksum((uint16_t *)&packet, bytes)) {
963 log1("packet with bad UDP checksum received, ignoring");
964 return -2;
965 }
966 skip_udp_sum_check:
967
968 if (packet.data.cookie != htonl(DHCP_MAGIC)) {
969 bb_error_msg("packet with bad magic, ignoring");
970 return -2;
971 }
972
973 log1("received %s", "a packet");
974 udhcp_dump_packet(&packet.data);
975
976 bytes -= sizeof(packet.ip) + sizeof(packet.udp);
977 memcpy(dhcp_pkt, &packet.data, bytes);
978 return bytes;
979 }
980
981
982 /*** Main ***/
983
984 static int sockfd = -1;
985
986 #define LISTEN_NONE 0
987 #define LISTEN_KERNEL 1
988 #define LISTEN_RAW 2
989 static smallint listen_mode;
990
991 /* initial state: (re)start DHCP negotiation */
992 #define INIT_SELECTING 0
993 /* discover was sent, DHCPOFFER reply received */
994 #define REQUESTING 1
995 /* select/renew was sent, DHCPACK reply received */
996 #define BOUND 2
997 /* half of lease passed, want to renew it by sending unicast renew requests */
998 #define RENEWING 3
999 /* renew requests were not answered, lease is almost over, send broadcast renew */
1000 #define REBINDING 4
1001 /* manually requested renew (SIGUSR1) */
1002 #define RENEW_REQUESTED 5
1003 /* release, possibly manually requested (SIGUSR2) */
1004 #define RELEASED 6
1005 static smallint state;
1006
1007 static int udhcp_raw_socket(int ifindex)
1008 {
1009 int fd;
1010 struct sockaddr_ll sock;
1011
1012 log1("opening raw socket on ifindex %d", ifindex); //log2?
1013
1014 fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
1015 /* ^^^^^
1016 * SOCK_DGRAM: remove link-layer headers on input (SOCK_RAW keeps them)
1017 * ETH_P_IP: want to receive only packets with IPv4 eth type
1018 */
1019 log1("got raw socket fd"); //log2?
1020
1021 sock.sll_family = AF_PACKET;
1022 sock.sll_protocol = htons(ETH_P_IP);
1023 sock.sll_ifindex = ifindex;
1024 xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
1025
1026 #if 0 /* Several users reported breakage when BPF filter is used */
1027 if (CLIENT_PORT == 68) {
1028 /* Use only if standard port is in use */
1029 /*
1030 * I've selected not to see LL header, so BPF doesn't see it, too.
1031 * The filter may also pass non-IP and non-ARP packets, but we do
1032 * a more complete check when receiving the message in userspace.
1033 *
1034 * and filter shamelessly stolen from:
1035 *
1036 * http://www.flamewarmaster.de/software/dhcpclient/
1037 *
1038 * There are a few other interesting ideas on that page (look under
1039 * "Motivation"). Use of netlink events is most interesting. Think
1040 * of various network servers listening for events and reconfiguring.
1041 * That would obsolete sending HUP signals and/or make use of restarts.
1042 *
1043 * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
1044 * License: GPL v2.
1045 */
1046 static const struct sock_filter filter_instr[] = {
1047 /* load 9th byte (protocol) */
1048 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
1049 /* jump to L1 if it is IPPROTO_UDP, else to L4 */
1050 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
1051 /* L1: load halfword from offset 6 (flags and frag offset) */
1052 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
1053 /* jump to L4 if any bits in frag offset field are set, else to L2 */
1054 BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
1055 /* L2: skip IP header (load index reg with header len) */
1056 BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
1057 /* load udp destination port from halfword[header_len + 2] */
1058 BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
1059 /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
1060 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
1061 /* L3: accept packet ("accept 0x7fffffff bytes") */
1062 /* Accepting 0xffffffff works too but kernel 2.6.19 is buggy */
1063 BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
1064 /* L4: discard packet ("accept zero bytes") */
1065 BPF_STMT(BPF_RET|BPF_K, 0),
1066 };
1067 static const struct sock_fprog filter_prog = {
1068 .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
1069 /* casting const away: */
1070 .filter = (struct sock_filter *) filter_instr,
1071 };
1072 /* Ignoring error (kernel may lack support for this) */
1073 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
1074 sizeof(filter_prog)) >= 0)
1075 log1("attached filter to raw socket fd"); // log?
1076 }
1077 #endif
1078
1079 if (setsockopt_1(fd, SOL_PACKET, PACKET_AUXDATA) != 0) {
1080 if (errno != ENOPROTOOPT)
1081 log1("can't set PACKET_AUXDATA on raw socket");
1082 }
1083
1084 log1("created raw socket");
1085
1086 return fd;
1087 }
1088
1089 static void change_listen_mode(int new_mode)
1090 {
1091 log1("entering listen mode: %s",
1092 new_mode != LISTEN_NONE
1093 ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
1094 : "none"
1095 );
1096
1097 listen_mode = new_mode;
1098 if (sockfd >= 0) {
1099 close(sockfd);
1100 sockfd = -1;
1101 }
1102 if (new_mode == LISTEN_KERNEL)
1103 sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
1104 else if (new_mode != LISTEN_NONE)
1105 sockfd = udhcp_raw_socket(client_config.ifindex);
1106 /* else LISTEN_NONE: sockfd stays closed */
1107 }
1108
1109 /* Called only on SIGUSR1 */
1110 static void perform_renew(void)
1111 {
1112 bb_error_msg("performing DHCP renew");
1113 switch (state) {
1114 case BOUND:
1115 change_listen_mode(LISTEN_RAW); // zzz
1116 case RENEWING:
1117 case REBINDING:
1118 // state = RENEW_REQUESTED; // zzz
1119 // break;
1120 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
1121 case REQUESTING:
1122 case RELEASED:
1123 change_listen_mode(LISTEN_RAW);
1124 state = INIT_SELECTING;
1125 break;
1126 case INIT_SELECTING:
1127 break;
1128 }
1129 }
1130
1131 static void perform_release(uint32_t server_addr, uint32_t requested_ip)
1132 {
1133 char buffer[sizeof("255.255.255.255")];
1134 struct in_addr temp_addr;
1135
1136 /* send release packet */
1137 if (state == BOUND || state == RENEWING || state == REBINDING) {
1138 temp_addr.s_addr = server_addr;
1139 strcpy(buffer, inet_ntoa(temp_addr));
1140 temp_addr.s_addr = requested_ip;
1141 bb_error_msg("unicasting a release of %s to %s",
1142 inet_ntoa(temp_addr), buffer);
1143 send_release(server_addr, requested_ip); /* unicast */
1144 udhcp_run_script(NULL, "deconfig");
1145 }
1146 bb_error_msg("entering released state");
1147
1148 change_listen_mode(LISTEN_NONE);
1149 state = RELEASED;
1150 }
1151
1152 static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
1153 {
1154 uint8_t *storage;
1155 int len = strnlen(str, 255);
1156 storage = xzalloc(len + extra + OPT_DATA);
1157 storage[OPT_CODE] = code;
1158 storage[OPT_LEN] = len + extra;
1159 memcpy(storage + extra + OPT_DATA, str, len);
1160 return storage;
1161 }
1162
1163 #if BB_MMU
1164 static void client_background(void)
1165 {
1166 bb_daemonize(0);
1167 logmode &= ~LOGMODE_STDIO;
1168 /* rewrite pidfile, as our pid is different now */
1169 write_pidfile(client_config.pidfile);
1170 }
1171 #endif
1172
1173 //usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
1174 //usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
1175 //usage:#else
1176 //usage:# define IF_UDHCP_VERBOSE(...)
1177 //usage:#endif
1178 //usage:#define udhcpc_trivial_usage
1179 //usage: "[-fbq"IF_UDHCP_VERBOSE("v")"RB]"IF_FEATURE_UDHCPC_ARPING(" [-a[MSEC]]")" [-t N] [-T SEC] [-A SEC/-n]\n"
1180 //usage: " [-i IFACE]"IF_FEATURE_UDHCP_PORT(" [-P PORT]")" [-s PROG] [-p PIDFILE]\n"
1181 //usage: " [-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]..."
1182 //usage:#define udhcpc_full_usage "\n"
1183 //usage: IF_LONG_OPTS(
1184 //usage: "\n -i,--interface IFACE Interface to use (default eth0)"
1185 //usage: IF_FEATURE_UDHCP_PORT(
1186 //usage: "\n -P,--client-port PORT Use PORT (default 68)"
1187 //usage: )
1188 //usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
1189 //usage: "\n -p,--pidfile FILE Create pidfile"
1190 //usage: "\n -B,--broadcast Request broadcast replies"
1191 //usage: "\n -t,--retries N Send up to N discover packets (default 3)"
1192 //usage: "\n -T,--timeout SEC Pause between packets (default 3)"
1193 //usage: "\n -A,--tryagain SEC Wait if lease is not obtained (default 20)"
1194 //usage: "\n -n,--now Exit if lease is not obtained"
1195 //usage: "\n -q,--quit Exit after obtaining lease"
1196 //usage: "\n -R,--release Release IP on exit"
1197 //usage: "\n -f,--foreground Run in foreground"
1198 //usage: USE_FOR_MMU(
1199 //usage: "\n -b,--background Background if lease is not obtained"
1200 //usage: )
1201 //usage: "\n -S,--syslog Log to syslog too"
1202 //usage: IF_FEATURE_UDHCPC_ARPING(
1203 //usage: "\n -a[MSEC],--arping[=MSEC] Validate offered address with ARP ping"
1204 //usage: )
1205 //usage: "\n -r,--request IP Request this IP address"
1206 //usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
1207 //usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
1208 //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
1209 //usage: "\n Examples of string, numeric, and hex byte opts:"
1210 //usage: "\n -x hostname:bbox - option 12"
1211 //usage: "\n -x lease:3600 - option 51 (lease time)"
1212 //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
1213 //usage: "\n -F,--fqdn NAME Ask server to update DNS mapping for NAME"
1214 //usage: "\n -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')"
1215 //usage: "\n -C,--clientid-none Don't send MAC as client identifier"
1216 //usage: IF_UDHCP_VERBOSE(
1217 //usage: "\n -v Verbose"
1218 //usage: )
1219 //usage: )
1220 //usage: IF_NOT_LONG_OPTS(
1221 //usage: "\n -i IFACE Interface to use (default eth0)"
1222 //usage: IF_FEATURE_UDHCP_PORT(
1223 //usage: "\n -P PORT Use PORT (default 68)"
1224 //usage: )
1225 //usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
1226 //usage: "\n -p FILE Create pidfile"
1227 //usage: "\n -B Request broadcast replies"
1228 //usage: "\n -t N Send up to N discover packets (default 3)"
1229 //usage: "\n -T SEC Pause between packets (default 3)"
1230 //usage: "\n -A SEC Wait if lease is not obtained (default 20)"
1231 //usage: "\n -n Exit if lease is not obtained"
1232 //usage: "\n -q Exit after obtaining lease"
1233 //usage: "\n -R Release IP on exit"
1234 //usage: "\n -f Run in foreground"
1235 //usage: USE_FOR_MMU(
1236 //usage: "\n -b Background if lease is not obtained"
1237 //usage: )
1238 //usage: "\n -S Log to syslog too"
1239 //usage: IF_FEATURE_UDHCPC_ARPING(
1240 //usage: "\n -a[MSEC] Validate offered address with ARP ping"
1241 //usage: )
1242 //usage: "\n -r IP Request this IP address"
1243 //usage: "\n -o Don't request any options (unless -O is given)"
1244 //usage: "\n -O OPT Request option OPT from server (cumulative)"
1245 //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
1246 //usage: "\n Examples of string, numeric, and hex byte opts:"
1247 //usage: "\n -x hostname:bbox - option 12"
1248 //usage: "\n -x lease:3600 - option 51 (lease time)"
1249 //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
1250 //usage: "\n -F NAME Ask server to update DNS mapping for NAME"
1251 //usage: "\n -H,-h NAME Send NAME as client hostname (default none)"
1252 //usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
1253 //usage: "\n -C Don't send MAC as client identifier"
1254 //usage: IF_UDHCP_VERBOSE(
1255 //usage: "\n -v Verbose"
1256 //usage: )
1257 //usage: )
1258 //usage: "\nSignals:"
1259 //usage: "\n USR1 Renew current lease"
1260 //usage: "\n USR2 Release current lease"
1261
1262
1263 int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1264 int udhcpc_main(int argc UNUSED_PARAM, char **argv)
1265 {
1266 uint8_t *message;
1267 const char *str_V, *str_h, *str_F, *str_r;
1268 IF_FEATURE_UDHCPC_ARPING(const char *str_a = "2000";)
1269 IF_FEATURE_UDHCP_PORT(char *str_P;)
1270 void *clientid_mac_ptr;
1271 llist_t *list_O = NULL;
1272 llist_t *list_x = NULL;
1273 int tryagain_timeout = 20;
1274 int discover_timeout = 3;
1275 int discover_retries = 5;
1276 uint32_t server_addr = server_addr; /* for compiler */
1277 uint32_t requested_ip = 0;
1278 uint32_t xid = xid; /* for compiler */
1279 int packet_num;
1280 int timeout; /* must be signed */
1281 unsigned already_waited_sec;
1282 unsigned opt;
1283 IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
1284 int max_fd;
1285 int retval;
1286 fd_set rfds;
1287
1288 setup_common_bufsiz();
1289
1290 /* Default options */
1291 IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
1292 IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
1293 client_config.interface = "eth0";
1294 client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
1295 str_V = "udhcp "BB_VER;
1296
1297 /* Parse command line */
1298 /* O,x: list; -T,-t,-A take numeric param */
1299 opt_complementary = "O::x::T+:t+:A+" IF_UDHCP_VERBOSE(":vv") ;
1300
1301 IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
1302 opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:fB"
1303 "m" // zzz
1304 USE_FOR_MMU("b")
1305 IF_FEATURE_UDHCPC_ARPING("a::")
1306 IF_FEATURE_UDHCP_PORT("P:")
1307 "v"
1308 , &str_V, &str_h, &str_h, &str_F
1309 , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
1310 , &client_config.script /* s */
1311 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
1312 , &list_O
1313 , &list_x
1314 IF_FEATURE_UDHCPC_ARPING(, &str_a)
1315 IF_FEATURE_UDHCP_PORT(, &str_P)
1316 IF_UDHCP_VERBOSE(, &dhcp_verbose)
1317 );
1318 if (opt & (OPT_h|OPT_H)) {
1319 //msg added 2011-11
1320 bb_error_msg("option -h NAME is deprecated, use -x hostname:NAME");
1321 client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
1322 }
1323 if (opt & OPT_F) {
1324 /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
1325 client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
1326 /* Flag bits: 0000NEOS
1327 * S: 1 = Client requests server to update A RR in DNS as well as PTR
1328 * O: 1 = Server indicates to client that DNS has been updated regardless
1329 * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
1330 * not "host.domain.com". Format 0 is obsolete.
1331 * N: 1 = Client requests server to not update DNS (S must be 0 then)
1332 * Two [0] bytes which follow are deprecated and must be 0.
1333 */
1334 client_config.fqdn[OPT_DATA + 0] = 0x1;
1335 /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
1336 /*client_config.fqdn[OPT_DATA + 2] = 0; */
1337 }
1338 if (opt & OPT_r)
1339 requested_ip = inet_addr(str_r);
1340 #if ENABLE_FEATURE_UDHCP_PORT
1341 if (opt & OPT_P) {
1342 CLIENT_PORT = xatou16(str_P);
1343 SERVER_PORT = CLIENT_PORT - 1;
1344 }
1345 #endif
1346 IF_FEATURE_UDHCPC_ARPING(arpping_ms = xatou(str_a);)
1347 while (list_O) {
1348 char *optstr = llist_pop(&list_O);
1349 unsigned n = bb_strtou(optstr, NULL, 0);
1350 if (errno || n > 254) {
1351 n = udhcp_option_idx(optstr);
1352 n = dhcp_optflags[n].code;
1353 }
1354 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
1355 }
1356 if (!(opt & OPT_o)) {
1357 unsigned i, n;
1358 for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) {
1359 if (dhcp_optflags[i].flags & OPTION_REQ) {
1360 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
1361 }
1362 }
1363 }
1364 while (list_x) {
1365 char *optstr = llist_pop(&list_x);
1366 char *colon = strchr(optstr, ':');
1367 if (colon)
1368 *colon = ' ';
1369 /* now it looks similar to udhcpd's config file line:
1370 * "optname optval", using the common routine: */
1371 udhcp_str2optset(optstr, &client_config.options);
1372 }
1373
1374 if (opt & OPT_m) // zzz
1375 minpkt = 1;
1376
1377 if (udhcp_read_interface(client_config.interface,
1378 &client_config.ifindex,
1379 NULL,
1380 client_config.client_mac,
1381 &client_config.client_mtu)
1382 ) {
1383 return 1;
1384 }
1385
1386 clientid_mac_ptr = NULL;
1387 if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) {
1388 /* not suppressed and not set, set the default client ID */
1389 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
1390 client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
1391 clientid_mac_ptr = client_config.clientid + OPT_DATA+1;
1392 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1393 }
1394 if (str_V[0] != '\0') {
1395 // can drop -V, str_V, client_config.vendorclass,
1396 // but need to add "vendor" to the list of recognized
1397 // string opts for this to work;
1398 // and need to tweak add_client_options() too...
1399 // ...so the question is, should we?
1400 //bb_error_msg("option -V VENDOR is deprecated, use -x vendor:VENDOR");
1401 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
1402 }
1403
1404 #if !BB_MMU
1405 /* on NOMMU reexec (i.e., background) early */
1406 if (!(opt & OPT_f)) {
1407 bb_daemonize_or_rexec(0 /* flags */, argv);
1408 logmode = LOGMODE_NONE;
1409 }
1410 #endif
1411 if (opt & OPT_S) {
1412 openlog(applet_name, LOG_PID, LOG_DAEMON);
1413 logmode |= LOGMODE_SYSLOG;
1414 }
1415
1416 /* Make sure fd 0,1,2 are open */
1417 bb_sanitize_stdio();
1418 /* Equivalent of doing a fflush after every \n */
1419 setlinebuf(stdout);
1420 /* Create pidfile */
1421 write_pidfile(client_config.pidfile);
1422 /* Goes to stdout (unless NOMMU) and possibly syslog */
1423 bb_error_msg("started, v"BB_VER);
1424 /* Set up the signal pipe */
1425 udhcp_sp_setup();
1426 /* We want random_xid to be random... */
1427 srand(monotonic_us());
1428
1429 state = INIT_SELECTING;
1430 udhcp_run_script(NULL, "deconfig");
1431 change_listen_mode(LISTEN_RAW);
1432 packet_num = 0;
1433 timeout = 0;
1434 already_waited_sec = 0;
1435
1436 /* Main event loop. select() waits on signal pipe and possibly
1437 * on sockfd.
1438 * "continue" statements in code below jump to the top of the loop.
1439 */
1440 for (;;) {
1441 struct timeval tv;
1442 struct dhcp_packet packet;
1443 /* silence "uninitialized!" warning */
1444 unsigned timestamp_before_wait = timestamp_before_wait;
1445
1446 //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
1447
1448 /* Was opening raw or udp socket here
1449 * if (listen_mode != LISTEN_NONE && sockfd < 0),
1450 * but on fast network renew responses return faster
1451 * than we open sockets. Thus this code is moved
1452 * to change_listen_mode(). Thus we open listen socket
1453 * BEFORE we send renew request (see "case BOUND:"). */
1454
1455 max_fd = udhcp_sp_fd_set(&rfds, sockfd);
1456
1457 tv.tv_sec = timeout - already_waited_sec;
1458 tv.tv_usec = 0;
1459 retval = 0;
1460 /* If we already timed out, fall through with retval = 0, else... */
1461 if ((int)tv.tv_sec > 0) {
1462 log1("waiting on select %u seconds", (int)tv.tv_sec);
1463 timestamp_before_wait = (unsigned)monotonic_sec();
1464 retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
1465 if (retval < 0) {
1466 /* EINTR? A signal was caught, don't panic */
1467 if (errno == EINTR) {
1468 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1469 continue;
1470 }
1471 /* Else: an error occured, panic! */
1472 bb_perror_msg_and_die("select");
1473 }
1474 }
1475
1476 /* If timeout dropped to zero, time to become active:
1477 * resend discover/renew/whatever
1478 */
1479 if (retval == 0) {
1480 /* When running on a bridge, the ifindex may have changed
1481 * (e.g. if member interfaces were added/removed
1482 * or if the status of the bridge changed).
1483 * Refresh ifindex and client_mac:
1484 */
1485 if (udhcp_read_interface(client_config.interface,
1486 &client_config.ifindex,
1487 NULL,
1488 client_config.client_mac,
1489 &client_config.client_mtu)
1490 ) {
1491 goto ret0; /* iface is gone? */
1492 }
1493 if (clientid_mac_ptr)
1494 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1495
1496 /* We will restart the wait in any case */
1497 already_waited_sec = 0;
1498
1499 switch (state) {
1500 case INIT_SELECTING:
1501 if (!discover_retries || packet_num < discover_retries) {
1502 if (packet_num == 0)
1503 xid = random_xid();
1504 /* broadcast */
1505 send_discover(xid, requested_ip);
1506 timeout = discover_timeout;
1507 packet_num++;
1508 continue;
1509 }
1510 leasefail:
1511 udhcp_run_script(NULL, "leasefail");
1512 #if BB_MMU /* -b is not supported on NOMMU */
1513 if (opt & OPT_b) { /* background if no lease */
1514 bb_error_msg("no lease, forking to background");
1515 client_background();
1516 /* do not background again! */
1517 opt = ((opt & ~OPT_b) | OPT_f);
1518 } else
1519 #endif
1520 if (opt & OPT_n) { /* abort if no lease */
1521 bb_error_msg("no lease, failing");
1522 retval = 1;
1523 goto ret;
1524 }
1525 /* wait before trying again */
1526 timeout = tryagain_timeout;
1527 packet_num = 0;
1528 continue;
1529 case REQUESTING:
1530 if (packet_num < 3) {
1531 /* send broadcast select packet */
1532 send_select(xid, server_addr, requested_ip);
1533 timeout = discover_timeout;
1534 packet_num++;
1535 continue;
1536 }
1537 /* Timed out, go back to init state.
1538 * "discover...select...discover..." loops
1539 * were seen in the wild. Treat them similarly
1540 * to "no response to discover" case */
1541 change_listen_mode(LISTEN_RAW);
1542 state = INIT_SELECTING;
1543 goto leasefail;
1544 case BOUND:
1545 /* 1/2 lease passed, enter renewing state */
1546 state = RENEWING;
1547 client_config.first_secs = 0; /* make secs field count from 0 */
1548 change_listen_mode(LISTEN_RAW); // was: LISTEN_KERNEL -- zzz
1549 log1("entering renew state");
1550 /* fall right through */
1551 case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
1552 case_RENEW_REQUESTED:
1553 case RENEWING:
1554 if (timeout > 60) {
1555 /* send an unicast renew request */
1556 /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1557 * a new UDP socket for sending inside send_renew.
1558 * I hazard to guess existing listening socket
1559 * is somehow conflicting with it, but why is it
1560 * not deterministic then?! Strange.
1561 * Anyway, it does recover by eventually failing through
1562 * into INIT_SELECTING state.
1563 */
1564 send_renew(xid, server_addr, requested_ip);
1565 timeout >>= 1;
1566 continue;
1567 }
1568 /* Timed out, enter rebinding state */
1569 log1("entering rebinding state");
1570 state = REBINDING;
1571 /* fall right through */
1572 case REBINDING:
1573 /* Switch to bcast receive */
1574 change_listen_mode(LISTEN_RAW);
1575 /* Lease is *really* about to run out,
1576 * try to find DHCP server using broadcast */
1577 if (timeout > 0) {
1578 /* send a broadcast renew request */
1579 send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
1580 timeout >>= 1;
1581 continue;
1582 }
1583 /* Timed out, enter init state */
1584 bb_error_msg("lease lost, entering init state");
1585 udhcp_run_script(NULL, "deconfig");
1586 state = INIT_SELECTING;
1587 client_config.first_secs = 0; /* make secs field count from 0 */
1588 /*timeout = 0; - already is */
1589 packet_num = 0;
1590 continue;
1591 /* case RELEASED: */
1592 }
1593 /* yah, I know, *you* say it would never happen */
1594 timeout = INT_MAX;
1595 continue; /* back to main loop */
1596 } /* if select timed out */
1597
1598 /* select() didn't timeout, something happened */
1599
1600 /* Is it a signal? */
1601 /* note: udhcp_sp_read checks FD_ISSET before reading */
1602 switch (udhcp_sp_read(&rfds)) {
1603 case SIGUSR1:
1604 client_config.first_secs = 0; /* make secs field count from 0 */
1605 // already_waited_sec = 0; /* shibby - this broke tomato renew button */
1606 perform_renew();
1607 if (state == RENEW_REQUESTED)
1608 // if (timeout > tryagain_timeout) /* shibby - this broke tomato renew button */
1609 // timeout = tryagain_timeout; /* shibby - this broke tomato renew button */
1610 goto case_RENEW_REQUESTED;
1611 /* Start things over */
1612 packet_num = 0;
1613 /* Kill any timeouts, user wants this to hurry along */
1614 timeout = 0;
1615 continue;
1616 case SIGUSR2:
1617 perform_release(server_addr, requested_ip);
1618 timeout = INT_MAX;
1619 continue;
1620 case SIGTERM:
1621 bb_error_msg("received %s", "SIGTERM");
1622 goto ret0;
1623 }
1624
1625 /* Is it a packet? */
1626 if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
1627 continue; /* no */
1628
1629 {
1630 int len;
1631
1632 /* A packet is ready, read it */
1633 if (listen_mode == LISTEN_KERNEL)
1634 len = udhcp_recv_kernel_packet(&packet, sockfd);
1635 else
1636 len = udhcp_recv_raw_packet(&packet, sockfd);
1637 if (len == -1) {
1638 /* Error is severe, reopen socket */
1639 bb_error_msg("read error: %s, reopening socket", strerror(errno));
1640 sleep(discover_timeout); /* 3 seconds by default */
1641 change_listen_mode(listen_mode); /* just close and reopen */
1642 }
1643 /* If this packet will turn out to be unrelated/bogus,
1644 * we will go back and wait for next one.
1645 * Be sure timeout is properly decreased. */
1646 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1647 if (len < 0)
1648 continue;
1649 }
1650
1651 if (packet.xid != xid) {
1652 log1("xid %x (our is %x), ignoring packet",
1653 (unsigned)packet.xid, (unsigned)xid);
1654 continue;
1655 }
1656
1657 /* Ignore packets that aren't for us */
1658 if (packet.hlen != 6
1659 || memcmp(packet.chaddr, client_config.client_mac, 6) != 0
1660 ) {
1661 //FIXME: need to also check that last 10 bytes are zero
1662 log1("chaddr does not match, ignoring packet"); // log2?
1663 continue;
1664 }
1665
1666 message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
1667 if (message == NULL) {
1668 bb_error_msg("no message type option, ignoring packet");
1669 continue;
1670 }
1671
1672 switch (state) {
1673 case INIT_SELECTING:
1674 /* Must be a DHCPOFFER */
1675 if (*message == DHCPOFFER) {
1676 uint8_t *temp;
1677
1678 /* What exactly is server's IP? There are several values.
1679 * Example DHCP offer captured with tchdump:
1680 *
1681 * 10.34.25.254:67 > 10.34.25.202:68 // IP header's src
1682 * BOOTP fields:
1683 * Your-IP 10.34.25.202
1684 * Server-IP 10.34.32.125 // "next server" IP
1685 * Gateway-IP 10.34.25.254 // relay's address (if DHCP relays are in use)
1686 * DHCP options:
1687 * DHCP-Message Option 53, length 1: Offer
1688 * Server-ID Option 54, length 4: 10.34.255.7 // "server ID"
1689 * Default-Gateway Option 3, length 4: 10.34.25.254 // router
1690 *
1691 * We think that real server IP (one to use in renew/release)
1692 * is one in Server-ID option. But I am not 100% sure.
1693 * IP header's src and Gateway-IP (same in this example)
1694 * might work too.
1695 * "Next server" and router are definitely wrong ones to use, though...
1696 */
1697 /* We used to ignore pcakets without DHCP_SERVER_ID.
1698 * I've got user reports from people who run "address-less" servers.
1699 * They either supply DHCP_SERVER_ID of 0.0.0.0 or don't supply it at all.
1700 * They say ISC DHCP client supports this case.
1701 */
1702 server_addr = 0;
1703 temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
1704 if (!temp) {
1705 bb_error_msg("no server ID, using 0.0.0.0");
1706 } else {
1707 /* it IS unaligned sometimes, don't "optimize" */
1708 move_from_unaligned32(server_addr, temp);
1709 }
1710 /*xid = packet.xid; - already is */
1711 requested_ip = packet.yiaddr;
1712
1713 /* enter requesting state */
1714 state = REQUESTING;
1715 timeout = 0;
1716 packet_num = 0;
1717 already_waited_sec = 0;
1718 }
1719 continue;
1720 case REQUESTING:
1721 case RENEWING:
1722 case RENEW_REQUESTED:
1723 case REBINDING:
1724 if (*message == DHCPACK) {
1725 unsigned start;
1726 uint32_t lease_seconds;
1727 struct in_addr temp_addr;
1728 uint8_t *temp;
1729
1730 temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
1731 if (!temp) {
1732 bb_error_msg("no lease time with ACK, using 1 hour lease");
1733 lease_seconds = 60 * 60;
1734 } else {
1735 /* it IS unaligned sometimes, don't "optimize" */
1736 move_from_unaligned32(lease_seconds, temp);
1737 lease_seconds = ntohl(lease_seconds);
1738 /* paranoia: must not be too small and not prone to overflows */
1739 if (lease_seconds < 0x10)
1740 lease_seconds = 0x10;
1741 if (lease_seconds >= 0x10000000)
1742 lease_seconds = 0x0fffffff;
1743 }
1744 #if ENABLE_FEATURE_UDHCPC_ARPING
1745 if (opt & OPT_a) {
1746 /* RFC 2131 3.1 paragraph 5:
1747 * "The client receives the DHCPACK message with configuration
1748 * parameters. The client SHOULD perform a final check on the
1749 * parameters (e.g., ARP for allocated network address), and notes
1750 * the duration of the lease specified in the DHCPACK message. At this
1751 * point, the client is configured. If the client detects that the
1752 * address is already in use (e.g., through the use of ARP),
1753 * the client MUST send a DHCPDECLINE message to the server and restarts
1754 * the configuration process..." */
1755 if (!arpping(packet.yiaddr,
1756 NULL,
1757 (uint32_t) 0,
1758 client_config.client_mac,
1759 client_config.interface,
1760 arpping_ms)
1761 ) {
1762 bb_error_msg("offered address is in use "
1763 "(got ARP reply), declining");
1764 send_decline(/*xid,*/ server_addr, packet.yiaddr);
1765
1766 if (state != REQUESTING)
1767 udhcp_run_script(NULL, "deconfig");
1768 change_listen_mode(LISTEN_RAW);
1769 state = INIT_SELECTING;
1770 client_config.first_secs = 0; /* make secs field count from 0 */
1771 requested_ip = 0;
1772 timeout = tryagain_timeout;
1773 packet_num = 0;
1774 already_waited_sec = 0;
1775 continue; /* back to main loop */
1776 }
1777 }
1778 #endif
1779 /* enter bound state */
1780 temp_addr.s_addr = packet.yiaddr;
1781 bb_error_msg("lease of %s obtained, lease time %u",
1782 inet_ntoa(temp_addr), (unsigned)lease_seconds);
1783 requested_ip = packet.yiaddr;
1784
1785 start = monotonic_sec();
1786 udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
1787 already_waited_sec = (unsigned)monotonic_sec() - start;
1788 timeout = lease_seconds / 2;
1789 if ((unsigned)timeout < already_waited_sec) {
1790 /* Something went wrong. Back to discover state */
1791 timeout = already_waited_sec = 0;
1792 }
1793
1794 state = BOUND;
1795 change_listen_mode(LISTEN_NONE);
1796 if (opt & OPT_q) { /* quit after lease */
1797 goto ret0;
1798 }
1799 /* future renew failures should not exit (JM) */
1800 opt &= ~OPT_n;
1801 #if BB_MMU /* NOMMU case backgrounded earlier */
1802 if (!(opt & OPT_f)) {
1803 client_background();
1804 /* do not background again! */
1805 opt = ((opt & ~OPT_b) | OPT_f);
1806 }
1807 #endif
1808 /* make future renew packets use different xid */
1809 /* xid = random_xid(); ...but why bother? */
1810
1811 continue; /* back to main loop */
1812 }
1813 if (*message == DHCPNAK) {
1814 /* If network has more than one DHCP server,
1815 * "wrong" server can reply first, with a NAK.
1816 * Do not interpret it as a NAK from "our" server.
1817 */
1818 if (server_addr != 0) {
1819 uint32_t svid;
1820 uint8_t *temp;
1821
1822 temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
1823 if (!temp) {
1824 non_matching_svid:
1825 log1("%s with wrong server ID, ignoring packet",
1826 "Received DHCP NAK"
1827 );
1828 continue;
1829 }
1830 move_from_unaligned32(svid, temp);
1831 if (svid != server_addr)
1832 goto non_matching_svid;
1833 }
1834 /* return to init state */
1835 bb_error_msg("received %s", "DHCP NAK");
1836 udhcp_run_script(&packet, "nak");
1837 if (state != REQUESTING)
1838 udhcp_run_script(NULL, "deconfig");
1839 change_listen_mode(LISTEN_RAW);
1840 sleep(3); /* avoid excessive network traffic */
1841 state = INIT_SELECTING;
1842 client_config.first_secs = 0; /* make secs field count from 0 */
1843 requested_ip = 0;
1844 timeout = 0;
1845 packet_num = 0;
1846 already_waited_sec = 0;
1847 }
1848 continue;
1849 /* case BOUND: - ignore all packets */
1850 /* case RELEASED: - ignore all packets */
1851 }
1852 /* back to main loop */
1853 } /* for (;;) - main loop ends */
1854
1855 ret0:
1856 if (opt & OPT_R) /* release on quit */
1857 perform_release(server_addr, requested_ip);
1858 retval = 0;
1859 ret:
1860 /*if (client_config.pidfile) - remove_pidfile has its own check */
1861 remove_pidfile(client_config.pidfile);
1862 return retval;
1863 }
Tomato firmware and modifications.