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Busybox: Upgrade to 1.21.1 (stable). lsof active.
[tomato.git] / release / src / router / busybox / networking / udhcp / d6_dhcpc.c
blobc44220bf94d6fd81d5270725b9c2f6a80ce1157b
1 /* vi: set sw=4 ts=4: */
2 /*
3 * DHCPv6 client.
4 *
5 * 2011-11.
6 * WARNING: THIS CODE IS INCOMPLETE. IT IS NOWHERE NEAR
7 * TO BE READY FOR PRODUCTION USE.
8 *
9 * Copyright (C) 2011 Denys Vlasenko.
10 *
11 * Licensed under GPLv2, see file LICENSE in this source tree.
12 */
13
14 //config:config UDHCPC6
15 //config: bool "udhcp client for DHCPv6 (udhcpc6)"
16 //config: default n # not yet ready
17 //config: depends on FEATURE_IPV6
18 //config: help
19 //config: udhcpc6 is a DHCPv6 client
20
21 //applet:IF_UDHCPC6(APPLET(udhcpc6, BB_DIR_USR_BIN, BB_SUID_DROP))
22
23 //kbuild:lib-$(CONFIG_UDHCPC6) += d6_dhcpc.o d6_packet.o d6_socket.o common.o socket.o signalpipe.o
24
25
26 #include <syslog.h>
27 /* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
28 #define WANT_PIDFILE 1
29 #include "common.h"
30 #include "dhcpd.h"
31 #include "dhcpc.h"
32 #include "d6_common.h"
33
34 #include <netinet/if_ether.h>
35 #include <netpacket/packet.h>
36 #include <linux/filter.h>
37
38 /* "struct client_config_t client_config" is in bb_common_bufsiz1 */
39
40
41 #if ENABLE_LONG_OPTS
42 static const char udhcpc6_longopts[] ALIGN1 =
43 "interface\0" Required_argument "i"
44 "now\0" No_argument "n"
45 "pidfile\0" Required_argument "p"
46 "quit\0" No_argument "q"
47 "release\0" No_argument "R"
48 "request\0" Required_argument "r"
49 "script\0" Required_argument "s"
50 "timeout\0" Required_argument "T"
51 "retries\0" Required_argument "t"
52 "tryagain\0" Required_argument "A"
53 "syslog\0" No_argument "S"
54 "request-option\0" Required_argument "O"
55 "no-default-options\0" No_argument "o"
56 "foreground\0" No_argument "f"
57 "background\0" No_argument "b"
58 /// IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
59 IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
60 ;
61 #endif
62 /* Must match getopt32 option string order */
63 enum {
64 OPT_i = 1 << 0,
65 OPT_n = 1 << 1,
66 OPT_p = 1 << 2,
67 OPT_q = 1 << 3,
68 OPT_R = 1 << 4,
69 OPT_r = 1 << 5,
70 OPT_s = 1 << 6,
71 OPT_T = 1 << 7,
72 OPT_t = 1 << 8,
73 OPT_S = 1 << 9,
74 OPT_A = 1 << 10,
75 OPT_O = 1 << 11,
76 OPT_o = 1 << 12,
77 OPT_x = 1 << 13,
78 OPT_f = 1 << 14,
79 /* The rest has variable bit positions, need to be clever */
80 OPTBIT_f = 14,
81 USE_FOR_MMU( OPTBIT_b,)
82 ///IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
83 IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
84 USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
85 ///IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
86 IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
87 };
88
89
90 /*** Utility functions ***/
91
92 static void *d6_find_option(uint8_t *option, uint8_t *option_end, unsigned code)
93 {
94 /* "length minus 4" */
95 int len_m4 = option_end - option - 4;
96 while (len_m4 >= 0) {
97 /* Next option's len is too big? */
98 if (option[3] > len_m4)
99 return NULL; /* yes. bogus packet! */
100 /* So far we treat any opts with code >255
101 * or len >255 as bogus, and stop at once.
102 * This simplifies big-endian handling.
103 */
104 if (option[0] != 0 || option[2] != 0)
105 return NULL;
106 /* Option seems to be valid */
107 /* Does its code match? */
108 if (option[1] == code)
109 return option; /* yes! */
110 option += option[3] + 4;
111 len_m4 -= option[3] + 4;
112 }
113 return NULL;
114 }
115
116 static void *d6_copy_option(uint8_t *option, uint8_t *option_end, unsigned code)
117 {
118 uint8_t *opt = d6_find_option(option, option_end, code);
119 if (!opt)
120 return opt;
121 return memcpy(xmalloc(opt[3] + 4), opt, opt[3] + 4);
122 }
123
124 static void *d6_store_blob(void *dst, const void *src, unsigned len)
125 {
126 memcpy(dst, src, len);
127 return dst + len;
128 }
129
130
131 /*** Script execution code ***/
132
133 static char** new_env(void)
134 {
135 client6_data.env_ptr = xrealloc_vector(client6_data.env_ptr, 3, client6_data.env_idx);
136 return &client6_data.env_ptr[client6_data.env_idx++];
137 }
138
139 /* put all the parameters into the environment */
140 static void option_to_env(uint8_t *option, uint8_t *option_end)
141 {
142 /* "length minus 4" */
143 int len_m4 = option_end - option - 4;
144 while (len_m4 >= 0) {
145 uint32_t v32;
146 char ipv6str[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")];
147
148 if (option[0] != 0 || option[2] != 0)
149 break;
150
151 switch (option[1]) {
152 //case D6_OPT_CLIENTID:
153 //case D6_OPT_SERVERID:
154 case D6_OPT_IA_NA:
155 case D6_OPT_IA_PD:
156 option_to_env(option + 16, option + 4 + option[3]);
157 break;
158 //case D6_OPT_IA_TA:
159 case D6_OPT_IAADDR:
160 /* 0 1 2 3
161 * 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
162 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
163 * | OPTION_IAADDR | option-len |
164 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
165 * | |
166 * | IPv6 address |
167 * | |
168 * | |
169 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
170 * | preferred-lifetime |
171 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
172 * | valid-lifetime |
173 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
174 */
175 sprint_nip6(ipv6str, option + 4);
176 *new_env() = xasprintf("ipv6=%s", ipv6str);
177
178 move_from_unaligned32(v32, option + 4 + 16 + 4);
179 *new_env() = xasprintf("lease=%u", (unsigned)v32);
180 break;
181
182 //case D6_OPT_ORO:
183 //case D6_OPT_PREFERENCE:
184 //case D6_OPT_ELAPSED_TIME:
185 //case D6_OPT_RELAY_MSG:
186 //case D6_OPT_AUTH:
187 //case D6_OPT_UNICAST:
188 //case D6_OPT_STATUS_CODE:
189 //case D6_OPT_RAPID_COMMIT:
190 //case D6_OPT_USER_CLASS:
191 //case D6_OPT_VENDOR_CLASS:
192 //case D6_OPT_VENDOR_OPTS:
193 //case D6_OPT_INTERFACE_ID:
194 //case D6_OPT_RECONF_MSG:
195 //case D6_OPT_RECONF_ACCEPT:
196
197 case D6_OPT_IAPREFIX:
198 /* 0 1 2 3
199 * 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
200 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
201 * | OPTION_IAPREFIX | option-length |
202 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
203 * | preferred-lifetime |
204 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
205 * | valid-lifetime |
206 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
207 * | prefix-length | |
208 * +-+-+-+-+-+-+-+-+ IPv6 prefix |
209 * | (16 octets) |
210 * | |
211 * | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
212 * | |
213 * +-+-+-+-+-+-+-+-+
214 */
215 //move_from_unaligned32(v32, option + 4 + 4);
216 //*new_env() = xasprintf("lease=%u", (unsigned)v32);
217
218 sprint_nip6(ipv6str, option + 4 + 4 + 1);
219 *new_env() = xasprintf("ipv6prefix=%s/%u", ipv6str, (unsigned)(option[4 + 4]));
220 }
221 option += 4 + option[3];
222 len_m4 -= 4 + option[3];
223 }
224 }
225
226 static char **fill_envp(struct d6_packet *packet)
227 {
228 char **envp, **curr;
229
230 client6_data.env_ptr = NULL;
231 client6_data.env_idx = 0;
232
233 *new_env() = xasprintf("interface=%s", client_config.interface);
234
235 if (packet)
236 option_to_env(packet->d6_options, packet->d6_options + sizeof(packet->d6_options));
237
238 envp = curr = client6_data.env_ptr;
239 while (*curr)
240 putenv(*curr++);
241
242 return envp;
243 }
244
245 /* Call a script with a par file and env vars */
246 static void d6_run_script(struct d6_packet *packet, const char *name)
247 {
248 char **envp, **curr;
249 char *argv[3];
250
251 envp = fill_envp(packet);
252
253 /* call script */
254 log1("Executing %s %s", client_config.script, name);
255 argv[0] = (char*) client_config.script;
256 argv[1] = (char*) name;
257 argv[2] = NULL;
258 spawn_and_wait(argv);
259
260 for (curr = envp; *curr; curr++) {
261 log2(" %s", *curr);
262 bb_unsetenv_and_free(*curr);
263 }
264 free(envp);
265 }
266
267
268 /*** Sending/receiving packets ***/
269
270 static ALWAYS_INLINE uint32_t random_xid(void)
271 {
272 uint32_t t = rand() & htonl(0x00ffffff);
273 return t;
274 }
275
276 /* Initialize the packet with the proper defaults */
277 static uint8_t *init_d6_packet(struct d6_packet *packet, char type, uint32_t xid)
278 {
279 struct d6_option *clientid;
280
281 memset(packet, 0, sizeof(*packet));
282
283 packet->d6_xid32 = xid;
284 packet->d6_msg_type = type;
285
286 clientid = (void*)client_config.clientid;
287 return d6_store_blob(packet->d6_options, clientid, clientid->len + 2+2);
288 }
289
290 static uint8_t *add_d6_client_options(uint8_t *ptr)
291 {
292 return ptr;
293 //uint8_t c;
294 //int i, end, len;
295
296 /* Add a "param req" option with the list of options we'd like to have
297 * from stubborn DHCP servers. Pull the data from the struct in common.c.
298 * No bounds checking because it goes towards the head of the packet. */
299 //...
300
301 /* Add -x options if any */
302 //...
303 }
304
305 static int d6_mcast_from_client_config_ifindex(struct d6_packet *packet, uint8_t *end)
306 {
307 static const uint8_t FF02__1_2[16] = {
308 0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
309 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02,
310 };
311
312 return d6_send_raw_packet(
313 packet, (end - (uint8_t*) packet),
314 /*src*/ NULL, CLIENT_PORT,
315 /*dst*/ (struct in6_addr*)FF02__1_2, SERVER_PORT, MAC_BCAST_ADDR,
316 client_config.ifindex
317 );
318 }
319
320 /* Milticast a DHCPv6 Solicit packet to the network, with an optionally requested IP.
321 *
322 * RFC 3315 17.1.1. Creation of Solicit Messages
323 *
324 * The client MUST include a Client Identifier option to identify itself
325 * to the server. The client includes IA options for any IAs to which
326 * it wants the server to assign addresses. The client MAY include
327 * addresses in the IAs as a hint to the server about addresses for
328 * which the client has a preference. ...
329 *
330 * The client uses IA_NA options to request the assignment of non-
331 * temporary addresses and uses IA_TA options to request the assignment
332 * of temporary addresses. Either IA_NA or IA_TA options, or a
333 * combination of both, can be included in DHCP messages.
334 *
335 * The client SHOULD include an Option Request option (see section 22.7)
336 * to indicate the options the client is interested in receiving. The
337 * client MAY additionally include instances of those options that are
338 * identified in the Option Request option, with data values as hints to
339 * the server about parameter values the client would like to have
340 * returned.
341 *
342 * The client includes a Reconfigure Accept option (see section 22.20)
343 * if the client is willing to accept Reconfigure messages from the
344 * server.
345 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
346 | OPTION_CLIENTID | option-len |
347 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
348 . .
349 . DUID .
350 . (variable length) .
351 . .
352 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
353
354
355 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
356 | OPTION_IA_NA | option-len |
357 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
358 | IAID (4 octets) |
359 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
360 | T1 |
361 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
362 | T2 |
363 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
364 | |
365 . IA_NA-options .
366 . .
367 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
368
369
370 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
371 | OPTION_IAADDR | option-len |
372 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
373 | |
374 | IPv6 address |
375 | |
376 | |
377 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
378 | preferred-lifetime |
379 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
380 | valid-lifetime |
381 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
382 . .
383 . IAaddr-options .
384 . .
385 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
386
387
388 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
389 | OPTION_ORO | option-len |
390 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
391 | requested-option-code-1 | requested-option-code-2 |
392 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
393 | ... |
394 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
395
396
397 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
398 | OPTION_RECONF_ACCEPT | 0 |
399 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
400 */
401 /* NOINLINE: limit stack usage in caller */
402 static NOINLINE int send_d6_discover(uint32_t xid, struct in6_addr *requested_ipv6)
403 {
404 struct d6_packet packet;
405 uint8_t *opt_ptr;
406 unsigned len;
407
408 /* Fill in: msg type, client id */
409 opt_ptr = init_d6_packet(&packet, D6_MSG_SOLICIT, xid);
410
411 /* Create new IA_NA, optionally with included IAADDR with requested IP */
412 free(client6_data.ia_na);
413 len = requested_ipv6 ? 2+2+4+4+4 + 2+2+16+4+4 : 2+2+4+4+4;
414 client6_data.ia_na = xzalloc(len);
415 client6_data.ia_na->code = D6_OPT_IA_NA;
416 client6_data.ia_na->len = len - 4;
417 *(uint32_t*)client6_data.ia_na->data = rand(); /* IAID */
418 if (requested_ipv6) {
419 struct d6_option *iaaddr = (void*)(client6_data.ia_na->data + 4+4+4);
420 iaaddr->code = D6_OPT_IAADDR;
421 iaaddr->len = 16+4+4;
422 memcpy(iaaddr->data, requested_ipv6, 16);
423 }
424 opt_ptr = d6_store_blob(opt_ptr, client6_data.ia_na, len);
425
426 /* Add options:
427 * "param req" option according to -O, options specified with -x
428 */
429 opt_ptr = add_d6_client_options(opt_ptr);
430
431 bb_info_msg("Sending discover...");
432 return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
433 }
434
435 /* Multicast a DHCPv6 request message
436 *
437 * RFC 3315 18.1.1. Creation and Transmission of Request Messages
438 *
439 * The client uses a Request message to populate IAs with addresses and
440 * obtain other configuration information. The client includes one or
441 * more IA options in the Request message. The server then returns
442 * addresses and other information about the IAs to the client in IA
443 * options in a Reply message.
444 *
445 * The client generates a transaction ID and inserts this value in the
446 * "transaction-id" field.
447 *
448 * The client places the identifier of the destination server in a
449 * Server Identifier option.
450 *
451 * The client MUST include a Client Identifier option to identify itself
452 * to the server. The client adds any other appropriate options,
453 * including one or more IA options (if the client is requesting that
454 * the server assign it some network addresses).
455 *
456 * The client MUST include an Option Request option (see section 22.7)
457 * to indicate the options the client is interested in receiving. The
458 * client MAY include options with data values as hints to the server
459 * about parameter values the client would like to have returned.
460 *
461 * The client includes a Reconfigure Accept option (see section 22.20)
462 * indicating whether or not the client is willing to accept Reconfigure
463 * messages from the server.
464 */
465 /* NOINLINE: limit stack usage in caller */
466 static NOINLINE int send_d6_select(uint32_t xid)
467 {
468 struct d6_packet packet;
469 uint8_t *opt_ptr;
470
471 /* Fill in: msg type, client id */
472 opt_ptr = init_d6_packet(&packet, D6_MSG_REQUEST, xid);
473
474 /* server id */
475 opt_ptr = d6_store_blob(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
476 /* IA NA (contains requested IP) */
477 opt_ptr = d6_store_blob(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
478
479 /* Add options:
480 * "param req" option according to -O, options specified with -x
481 */
482 opt_ptr = add_d6_client_options(opt_ptr);
483
484 bb_info_msg("Sending select...");
485 return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
486 }
487
488 /* Unicast or broadcast a DHCP renew message
489 *
490 * RFC 3315 18.1.3. Creation and Transmission of Renew Messages
491 *
492 * To extend the valid and preferred lifetimes for the addresses
493 * associated with an IA, the client sends a Renew message to the server
494 * from which the client obtained the addresses in the IA containing an
495 * IA option for the IA. The client includes IA Address options in the
496 * IA option for the addresses associated with the IA. The server
497 * determines new lifetimes for the addresses in the IA according to the
498 * administrative configuration of the server. The server may also add
499 * new addresses to the IA. The server may remove addresses from the IA
500 * by setting the preferred and valid lifetimes of those addresses to
501 * zero.
502 *
503 * The server controls the time at which the client contacts the server
504 * to extend the lifetimes on assigned addresses through the T1 and T2
505 * parameters assigned to an IA.
506 *
507 * At time T1 for an IA, the client initiates a Renew/Reply message
508 * exchange to extend the lifetimes on any addresses in the IA. The
509 * client includes an IA option with all addresses currently assigned to
510 * the IA in its Renew message.
511 *
512 * If T1 or T2 is set to 0 by the server (for an IA_NA) or there are no
513 * T1 or T2 times (for an IA_TA), the client may send a Renew or Rebind
514 * message, respectively, at the client's discretion.
515 *
516 * The client sets the "msg-type" field to RENEW. The client generates
517 * a transaction ID and inserts this value in the "transaction-id"
518 * field.
519 *
520 * The client places the identifier of the destination server in a
521 * Server Identifier option.
522 *
523 * The client MUST include a Client Identifier option to identify itself
524 * to the server. The client adds any appropriate options, including
525 * one or more IA options. The client MUST include the list of
526 * addresses the client currently has associated with the IAs in the
527 * Renew message.
528 *
529 * The client MUST include an Option Request option (see section 22.7)
530 * to indicate the options the client is interested in receiving. The
531 * client MAY include options with data values as hints to the server
532 * about parameter values the client would like to have returned.
533 */
534 /* NOINLINE: limit stack usage in caller */
535 static NOINLINE int send_d6_renew(uint32_t xid, struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
536 {
537 struct d6_packet packet;
538 uint8_t *opt_ptr;
539
540 /* Fill in: msg type, client id */
541 opt_ptr = init_d6_packet(&packet, DHCPREQUEST, xid);
542
543 /* server id */
544 opt_ptr = d6_store_blob(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
545 /* IA NA (contains requested IP) */
546 opt_ptr = d6_store_blob(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
547
548 /* Add options:
549 * "param req" option according to -O, options specified with -x
550 */
551 opt_ptr = add_d6_client_options(opt_ptr);
552
553 bb_info_msg("Sending renew...");
554 if (server_ipv6)
555 return d6_send_kernel_packet(
556 &packet, (opt_ptr - (uint8_t*) &packet),
557 our_cur_ipv6, CLIENT_PORT,
558 server_ipv6, SERVER_PORT
559 );
560 return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
561 }
562
563 /* Unicast a DHCP release message */
564 static int send_d6_release(struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
565 {
566 struct d6_packet packet;
567 uint8_t *opt_ptr;
568
569 /* Fill in: msg type, client id */
570 opt_ptr = init_d6_packet(&packet, D6_MSG_RELEASE, random_xid());
571 /* server id */
572 opt_ptr = d6_store_blob(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
573 /* IA NA (contains our current IP) */
574 opt_ptr = d6_store_blob(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
575
576 bb_info_msg("Sending release...");
577 return d6_send_kernel_packet(
578 &packet, (opt_ptr - (uint8_t*) &packet),
579 our_cur_ipv6, CLIENT_PORT,
580 server_ipv6, SERVER_PORT
581 );
582 }
583
584 /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
585 /* NOINLINE: limit stack usage in caller */
586 static NOINLINE int d6_recv_raw_packet(struct in6_addr *peer_ipv6
587 UNUSED_PARAM
588 , struct d6_packet *d6_pkt, int fd)
589 {
590 int bytes;
591 struct ip6_udp_d6_packet packet;
592
593 bytes = safe_read(fd, &packet, sizeof(packet));
594 if (bytes < 0) {
595 log1("Packet read error, ignoring");
596 /* NB: possible down interface, etc. Caller should pause. */
597 return bytes; /* returns -1 */
598 }
599
600 if (bytes < (int) (sizeof(packet.ip6) + sizeof(packet.udp))) {
601 log1("Packet is too short, ignoring");
602 return -2;
603 }
604
605 if (bytes < sizeof(packet.ip6) + ntohs(packet.ip6.ip6_plen)) {
606 /* packet is bigger than sizeof(packet), we did partial read */
607 log1("Oversized packet, ignoring");
608 return -2;
609 }
610
611 /* ignore any extra garbage bytes */
612 bytes = sizeof(packet.ip6) + ntohs(packet.ip6.ip6_plen);
613
614 /* make sure its the right packet for us, and that it passes sanity checks */
615 if (packet.ip6.ip6_nxt != IPPROTO_UDP
616 || (packet.ip6.ip6_vfc >> 4) != 6
617 || packet.udp.dest != htons(CLIENT_PORT)
618 /* || bytes > (int) sizeof(packet) - can't happen */
619 || packet.udp.len != packet.ip6.ip6_plen
620 ) {
621 log1("Unrelated/bogus packet, ignoring");
622 return -2;
623 }
624
625 //How to do this for ipv6?
626 // /* verify UDP checksum. IP header has to be modified for this */
627 // memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
628 // /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
629 // packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
630 // check = packet.udp.check;
631 // packet.udp.check = 0;
632 // if (check && check != inet_cksum((uint16_t *)&packet, bytes)) {
633 // log1("Packet with bad UDP checksum received, ignoring");
634 // return -2;
635 // }
636
637 log1("Received a packet");
638 d6_dump_packet(&packet.data);
639
640 bytes -= sizeof(packet.ip6) + sizeof(packet.udp);
641 memcpy(d6_pkt, &packet.data, bytes);
642 return bytes;
643 }
644
645
646 /*** Main ***/
647
648 static int sockfd = -1;
649
650 #define LISTEN_NONE 0
651 #define LISTEN_KERNEL 1
652 #define LISTEN_RAW 2
653 static smallint listen_mode;
654
655 /* initial state: (re)start DHCP negotiation */
656 #define INIT_SELECTING 0
657 /* discover was sent, DHCPOFFER reply received */
658 #define REQUESTING 1
659 /* select/renew was sent, DHCPACK reply received */
660 #define BOUND 2
661 /* half of lease passed, want to renew it by sending unicast renew requests */
662 #define RENEWING 3
663 /* renew requests were not answered, lease is almost over, send broadcast renew */
664 #define REBINDING 4
665 /* manually requested renew (SIGUSR1) */
666 #define RENEW_REQUESTED 5
667 /* release, possibly manually requested (SIGUSR2) */
668 #define RELEASED 6
669 static smallint state;
670
671 static int d6_raw_socket(int ifindex)
672 {
673 int fd;
674 struct sockaddr_ll sock;
675
676 /*
677 * Comment:
678 *
679 * I've selected not to see LL header, so BPF doesn't see it, too.
680 * The filter may also pass non-IP and non-ARP packets, but we do
681 * a more complete check when receiving the message in userspace.
682 *
683 * and filter shamelessly stolen from:
684 *
685 * http://www.flamewarmaster.de/software/dhcpclient/
686 *
687 * There are a few other interesting ideas on that page (look under
688 * "Motivation"). Use of netlink events is most interesting. Think
689 * of various network servers listening for events and reconfiguring.
690 * That would obsolete sending HUP signals and/or make use of restarts.
691 *
692 * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
693 * License: GPL v2.
694 *
695 * TODO: make conditional?
696 */
697 #if 0
698 static const struct sock_filter filter_instr[] = {
699 /* load 9th byte (protocol) */
700 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
701 /* jump to L1 if it is IPPROTO_UDP, else to L4 */
702 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
703 /* L1: load halfword from offset 6 (flags and frag offset) */
704 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
705 /* jump to L4 if any bits in frag offset field are set, else to L2 */
706 BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
707 /* L2: skip IP header (load index reg with header len) */
708 BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
709 /* load udp destination port from halfword[header_len + 2] */
710 BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
711 /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
712 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
713 /* L3: accept packet */
714 BPF_STMT(BPF_RET|BPF_K, 0xffffffff),
715 /* L4: discard packet */
716 BPF_STMT(BPF_RET|BPF_K, 0),
717 };
718 static const struct sock_fprog filter_prog = {
719 .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
720 /* casting const away: */
721 .filter = (struct sock_filter *) filter_instr,
722 };
723 #endif
724
725 log1("Opening raw socket on ifindex %d", ifindex); //log2?
726
727 fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IPV6));
728 log1("Got raw socket fd %d", fd); //log2?
729
730 sock.sll_family = AF_PACKET;
731 sock.sll_protocol = htons(ETH_P_IPV6);
732 sock.sll_ifindex = ifindex;
733 xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
734
735 #if 0
736 if (CLIENT_PORT == 68) {
737 /* Use only if standard port is in use */
738 /* Ignoring error (kernel may lack support for this) */
739 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
740 sizeof(filter_prog)) >= 0)
741 log1("Attached filter to raw socket fd %d", fd); // log?
742 }
743 #endif
744
745 log1("Created raw socket");
746
747 return fd;
748 }
749
750 static void change_listen_mode(int new_mode)
751 {
752 log1("Entering listen mode: %s",
753 new_mode != LISTEN_NONE
754 ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
755 : "none"
756 );
757
758 listen_mode = new_mode;
759 if (sockfd >= 0) {
760 close(sockfd);
761 sockfd = -1;
762 }
763 if (new_mode == LISTEN_KERNEL)
764 sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
765 else if (new_mode != LISTEN_NONE)
766 sockfd = d6_raw_socket(client_config.ifindex);
767 /* else LISTEN_NONE: sockfd stays closed */
768 }
769
770 /* Called only on SIGUSR1 */
771 static void perform_renew(void)
772 {
773 bb_info_msg("Performing a DHCP renew");
774 switch (state) {
775 case BOUND:
776 change_listen_mode(LISTEN_KERNEL);
777 case RENEWING:
778 case REBINDING:
779 state = RENEW_REQUESTED;
780 break;
781 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
782 d6_run_script(NULL, "deconfig");
783 case REQUESTING:
784 case RELEASED:
785 change_listen_mode(LISTEN_RAW);
786 state = INIT_SELECTING;
787 break;
788 case INIT_SELECTING:
789 break;
790 }
791 }
792
793 static void perform_d6_release(struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
794 {
795 /* send release packet */
796 if (state == BOUND || state == RENEWING || state == REBINDING) {
797 bb_info_msg("Unicasting a release");
798 send_d6_release(server_ipv6, our_cur_ipv6); /* unicast */
799 d6_run_script(NULL, "deconfig");
800 }
801 bb_info_msg("Entering released state");
802
803 change_listen_mode(LISTEN_NONE);
804 state = RELEASED;
805 }
806
807 ///static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
808 ///{
809 /// uint8_t *storage;
810 /// int len = strnlen(str, 255);
811 /// storage = xzalloc(len + extra + OPT_DATA);
812 /// storage[OPT_CODE] = code;
813 /// storage[OPT_LEN] = len + extra;
814 /// memcpy(storage + extra + OPT_DATA, str, len);
815 /// return storage;
816 ///}
817
818 #if BB_MMU
819 static void client_background(void)
820 {
821 bb_daemonize(0);
822 logmode &= ~LOGMODE_STDIO;
823 /* rewrite pidfile, as our pid is different now */
824 write_pidfile(client_config.pidfile);
825 }
826 #endif
827
828 //usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
829 //usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
830 //usage:#else
831 //usage:# define IF_UDHCP_VERBOSE(...)
832 //usage:#endif
833 //usage:#define udhcpc6_trivial_usage
834 //usage: "[-fbnq"IF_UDHCP_VERBOSE("v")"oR] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]\n"
835 //usage: " [-x OPT:VAL]... [-O OPT]..." IF_FEATURE_UDHCP_PORT(" [-P N]")
836 //usage:#define udhcpc6_full_usage "\n"
837 //usage: IF_LONG_OPTS(
838 //usage: "\n -i,--interface IFACE Interface to use (default eth0)"
839 //usage: "\n -p,--pidfile FILE Create pidfile"
840 //usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
841 //usage: "\n -B,--broadcast Request broadcast replies"
842 //usage: "\n -t,--retries N Send up to N discover packets"
843 //usage: "\n -T,--timeout N Pause between packets (default 3 seconds)"
844 //usage: "\n -A,--tryagain N Wait N seconds after failure (default 20)"
845 //usage: "\n -f,--foreground Run in foreground"
846 //usage: USE_FOR_MMU(
847 //usage: "\n -b,--background Background if lease is not obtained"
848 //usage: )
849 //usage: "\n -n,--now Exit if lease is not obtained"
850 //usage: "\n -q,--quit Exit after obtaining lease"
851 //usage: "\n -R,--release Release IP on exit"
852 //usage: "\n -S,--syslog Log to syslog too"
853 //usage: IF_FEATURE_UDHCP_PORT(
854 //usage: "\n -P,--client-port N Use port N (default 546)"
855 //usage: )
856 ////usage: IF_FEATURE_UDHCPC_ARPING(
857 ////usage: "\n -a,--arping Use arping to validate offered address"
858 ////usage: )
859 //usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
860 //usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
861 //usage: "\n -r,--request IP Request this IP address"
862 //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
863 //usage: "\n Examples of string, numeric, and hex byte opts:"
864 //usage: "\n -x hostname:bbox - option 12"
865 //usage: "\n -x lease:3600 - option 51 (lease time)"
866 //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
867 //usage: IF_UDHCP_VERBOSE(
868 //usage: "\n -v Verbose"
869 //usage: )
870 //usage: )
871 //usage: IF_NOT_LONG_OPTS(
872 //usage: "\n -i IFACE Interface to use (default eth0)"
873 //usage: "\n -p FILE Create pidfile"
874 //usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
875 //usage: "\n -B Request broadcast replies"
876 //usage: "\n -t N Send up to N discover packets"
877 //usage: "\n -T N Pause between packets (default 3 seconds)"
878 //usage: "\n -A N Wait N seconds (default 20) after failure"
879 //usage: "\n -f Run in foreground"
880 //usage: USE_FOR_MMU(
881 //usage: "\n -b Background if lease is not obtained"
882 //usage: )
883 //usage: "\n -n Exit if lease is not obtained"
884 //usage: "\n -q Exit after obtaining lease"
885 //usage: "\n -R Release IP on exit"
886 //usage: "\n -S Log to syslog too"
887 //usage: IF_FEATURE_UDHCP_PORT(
888 //usage: "\n -P N Use port N (default 546)"
889 //usage: )
890 ////usage: IF_FEATURE_UDHCPC_ARPING(
891 ////usage: "\n -a Use arping to validate offered address"
892 ////usage: )
893 //usage: "\n -O OPT Request option OPT from server (cumulative)"
894 //usage: "\n -o Don't request any options (unless -O is given)"
895 //usage: "\n -r IP Request this IP address"
896 //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
897 //usage: "\n Examples of string, numeric, and hex byte opts:"
898 //usage: "\n -x hostname:bbox - option 12"
899 //usage: "\n -x lease:3600 - option 51 (lease time)"
900 //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
901 //usage: IF_UDHCP_VERBOSE(
902 //usage: "\n -v Verbose"
903 //usage: )
904 //usage: )
905 //usage: "\nSignals:"
906 //usage: "\n USR1 Renew lease"
907 //usage: "\n USR2 Release lease"
908
909
910 int udhcpc6_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
911 int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
912 {
913 const char *str_r;
914 IF_FEATURE_UDHCP_PORT(char *str_P;)
915 void *clientid_mac_ptr;
916 llist_t *list_O = NULL;
917 llist_t *list_x = NULL;
918 int tryagain_timeout = 20;
919 int discover_timeout = 3;
920 int discover_retries = 3;
921 struct in6_addr srv6_buf;
922 struct in6_addr ipv6_buf;
923 struct in6_addr *requested_ipv6;
924 uint32_t xid = 0;
925 int packet_num;
926 int timeout; /* must be signed */
927 unsigned already_waited_sec;
928 unsigned opt;
929 int max_fd;
930 int retval;
931 fd_set rfds;
932
933 /* Default options */
934 IF_FEATURE_UDHCP_PORT(SERVER_PORT = 547;)
935 IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 546;)
936 client_config.interface = "eth0";
937 client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
938
939 /* Parse command line */
940 /* O,x: list; -T,-t,-A take numeric param */
941 opt_complementary = "O::x::T+:t+:A+" IF_UDHCP_VERBOSE(":vv") ;
942 IF_LONG_OPTS(applet_long_options = udhcpc6_longopts;)
943 opt = getopt32(argv, "i:np:qRr:s:T:t:SA:O:ox:f"
944 USE_FOR_MMU("b")
945 ///IF_FEATURE_UDHCPC_ARPING("a")
946 IF_FEATURE_UDHCP_PORT("P:")
947 "v"
948 , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
949 , &client_config.script /* s */
950 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
951 , &list_O
952 , &list_x
953 IF_FEATURE_UDHCP_PORT(, &str_P)
954 IF_UDHCP_VERBOSE(, &dhcp_verbose)
955 );
956 requested_ipv6 = NULL;
957 if (opt & OPT_r) {
958 if (inet_pton(AF_INET6, str_r, &ipv6_buf) <= 0)
959 bb_error_msg_and_die("bad IPv6 address '%s'", str_r);
960 requested_ipv6 = &ipv6_buf;
961 }
962 #if ENABLE_FEATURE_UDHCP_PORT
963 if (opt & OPT_P) {
964 CLIENT_PORT = xatou16(str_P);
965 SERVER_PORT = CLIENT_PORT - 1;
966 }
967 #endif
968 while (list_O) {
969 char *optstr = llist_pop(&list_O);
970 unsigned n = bb_strtou(optstr, NULL, 0);
971 if (errno || n > 254) {
972 n = udhcp_option_idx(optstr);
973 n = dhcp_optflags[n].code;
974 }
975 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
976 }
977 if (!(opt & OPT_o)) {
978 /*
979 unsigned i, n;
980 for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) {
981 if (dhcp_optflags[i].flags & OPTION_REQ) {
982 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
983 }
984 }
985 */
986 }
987 while (list_x) {
988 char *optstr = llist_pop(&list_x);
989 char *colon = strchr(optstr, ':');
990 if (colon)
991 *colon = ' ';
992 /* now it looks similar to udhcpd's config file line:
993 * "optname optval", using the common routine: */
994 udhcp_str2optset(optstr, &client_config.options);
995 }
996
997 if (udhcp_read_interface(client_config.interface,
998 &client_config.ifindex,
999 NULL,
1000 client_config.client_mac)
1001 ) {
1002 return 1;
1003 }
1004
1005 /* Create client ID based on mac, set clientid_mac_ptr */
1006 {
1007 struct d6_option *clientid;
1008 clientid = xzalloc(2+2+2+2+6);
1009 clientid->code = D6_OPT_CLIENTID;
1010 clientid->len = 2+2+6;
1011 clientid->data[1] = 3; /* DUID-LL */
1012 clientid->data[3] = 1; /* ethernet */
1013 clientid_mac_ptr = clientid->data + 2+2;
1014 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1015 client_config.clientid = (void*)clientid;
1016 }
1017
1018 #if !BB_MMU
1019 /* on NOMMU reexec (i.e., background) early */
1020 if (!(opt & OPT_f)) {
1021 bb_daemonize_or_rexec(0 /* flags */, argv);
1022 logmode = LOGMODE_NONE;
1023 }
1024 #endif
1025 if (opt & OPT_S) {
1026 openlog(applet_name, LOG_PID, LOG_DAEMON);
1027 logmode |= LOGMODE_SYSLOG;
1028 }
1029
1030 /* Make sure fd 0,1,2 are open */
1031 bb_sanitize_stdio();
1032 /* Equivalent of doing a fflush after every \n */
1033 setlinebuf(stdout);
1034 /* Create pidfile */
1035 write_pidfile(client_config.pidfile);
1036 /* Goes to stdout (unless NOMMU) and possibly syslog */
1037 bb_info_msg("%s (v"BB_VER") started", applet_name);
1038 /* Set up the signal pipe */
1039 udhcp_sp_setup();
1040 /* We want random_xid to be random... */
1041 srand(monotonic_us());
1042
1043 state = INIT_SELECTING;
1044 d6_run_script(NULL, "deconfig");
1045 change_listen_mode(LISTEN_RAW);
1046 packet_num = 0;
1047 timeout = 0;
1048 already_waited_sec = 0;
1049
1050 /* Main event loop. select() waits on signal pipe and possibly
1051 * on sockfd.
1052 * "continue" statements in code below jump to the top of the loop.
1053 */
1054 for (;;) {
1055 struct timeval tv;
1056 struct d6_packet packet;
1057 uint8_t *packet_end;
1058 /* silence "uninitialized!" warning */
1059 unsigned timestamp_before_wait = timestamp_before_wait;
1060
1061 //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
1062
1063 /* Was opening raw or udp socket here
1064 * if (listen_mode != LISTEN_NONE && sockfd < 0),
1065 * but on fast network renew responses return faster
1066 * than we open sockets. Thus this code is moved
1067 * to change_listen_mode(). Thus we open listen socket
1068 * BEFORE we send renew request (see "case BOUND:"). */
1069
1070 max_fd = udhcp_sp_fd_set(&rfds, sockfd);
1071
1072 tv.tv_sec = timeout - already_waited_sec;
1073 tv.tv_usec = 0;
1074 retval = 0;
1075 /* If we already timed out, fall through with retval = 0, else... */
1076 if ((int)tv.tv_sec > 0) {
1077 log1("Waiting on select %u seconds", (int)tv.tv_sec);
1078 timestamp_before_wait = (unsigned)monotonic_sec();
1079 retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
1080 if (retval < 0) {
1081 /* EINTR? A signal was caught, don't panic */
1082 if (errno == EINTR) {
1083 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1084 continue;
1085 }
1086 /* Else: an error occured, panic! */
1087 bb_perror_msg_and_die("select");
1088 }
1089 }
1090
1091 /* If timeout dropped to zero, time to become active:
1092 * resend discover/renew/whatever
1093 */
1094 if (retval == 0) {
1095 /* When running on a bridge, the ifindex may have changed
1096 * (e.g. if member interfaces were added/removed
1097 * or if the status of the bridge changed).
1098 * Refresh ifindex and client_mac:
1099 */
1100 if (udhcp_read_interface(client_config.interface,
1101 &client_config.ifindex,
1102 NULL,
1103 client_config.client_mac)
1104 ) {
1105 goto ret0; /* iface is gone? */
1106 }
1107 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1108
1109 /* We will restart the wait in any case */
1110 already_waited_sec = 0;
1111
1112 switch (state) {
1113 case INIT_SELECTING:
1114 if (!discover_retries || packet_num < discover_retries) {
1115 if (packet_num == 0)
1116 xid = random_xid();
1117 /* multicast */
1118 send_d6_discover(xid, requested_ipv6);
1119 timeout = discover_timeout;
1120 packet_num++;
1121 continue;
1122 }
1123 leasefail:
1124 d6_run_script(NULL, "leasefail");
1125 #if BB_MMU /* -b is not supported on NOMMU */
1126 if (opt & OPT_b) { /* background if no lease */
1127 bb_info_msg("No lease, forking to background");
1128 client_background();
1129 /* do not background again! */
1130 opt = ((opt & ~OPT_b) | OPT_f);
1131 } else
1132 #endif
1133 if (opt & OPT_n) { /* abort if no lease */
1134 bb_info_msg("No lease, failing");
1135 retval = 1;
1136 goto ret;
1137 }
1138 /* wait before trying again */
1139 timeout = tryagain_timeout;
1140 packet_num = 0;
1141 continue;
1142 case REQUESTING:
1143 if (!discover_retries || packet_num < discover_retries) {
1144 /* send multicast select packet */
1145 send_d6_select(xid);
1146 timeout = discover_timeout;
1147 packet_num++;
1148 continue;
1149 }
1150 /* Timed out, go back to init state.
1151 * "discover...select...discover..." loops
1152 * were seen in the wild. Treat them similarly
1153 * to "no response to discover" case */
1154 change_listen_mode(LISTEN_RAW);
1155 state = INIT_SELECTING;
1156 goto leasefail;
1157 case BOUND:
1158 /* 1/2 lease passed, enter renewing state */
1159 state = RENEWING;
1160 client_config.first_secs = 0; /* make secs field count from 0 */
1161 change_listen_mode(LISTEN_KERNEL);
1162 log1("Entering renew state");
1163 /* fall right through */
1164 case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
1165 case_RENEW_REQUESTED:
1166 case RENEWING:
1167 if (timeout > 60) {
1168 /* send an unicast renew request */
1169 /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1170 * a new UDP socket for sending inside send_renew.
1171 * I hazard to guess existing listening socket
1172 * is somehow conflicting with it, but why is it
1173 * not deterministic then?! Strange.
1174 * Anyway, it does recover by eventually failing through
1175 * into INIT_SELECTING state.
1176 */
1177 send_d6_renew(xid, &srv6_buf, requested_ipv6);
1178 timeout >>= 1;
1179 continue;
1180 }
1181 /* Timed out, enter rebinding state */
1182 log1("Entering rebinding state");
1183 state = REBINDING;
1184 /* fall right through */
1185 case REBINDING:
1186 /* Switch to bcast receive */
1187 change_listen_mode(LISTEN_RAW);
1188 /* Lease is *really* about to run out,
1189 * try to find DHCP server using broadcast */
1190 if (timeout > 0) {
1191 /* send a broadcast renew request */
1192 send_d6_renew(xid, /*server_ipv6:*/ NULL, requested_ipv6);
1193 timeout >>= 1;
1194 continue;
1195 }
1196 /* Timed out, enter init state */
1197 bb_info_msg("Lease lost, entering init state");
1198 d6_run_script(NULL, "deconfig");
1199 state = INIT_SELECTING;
1200 client_config.first_secs = 0; /* make secs field count from 0 */
1201 /*timeout = 0; - already is */
1202 packet_num = 0;
1203 continue;
1204 /* case RELEASED: */
1205 }
1206 /* yah, I know, *you* say it would never happen */
1207 timeout = INT_MAX;
1208 continue; /* back to main loop */
1209 } /* if select timed out */
1210
1211 /* select() didn't timeout, something happened */
1212
1213 /* Is it a signal? */
1214 /* note: udhcp_sp_read checks FD_ISSET before reading */
1215 switch (udhcp_sp_read(&rfds)) {
1216 case SIGUSR1:
1217 client_config.first_secs = 0; /* make secs field count from 0 */
1218 already_waited_sec = 0;
1219 perform_renew();
1220 if (state == RENEW_REQUESTED) {
1221 /* We might be either on the same network
1222 * (in which case renew might work),
1223 * or we might be on a completely different one
1224 * (in which case renew won't ever succeed).
1225 * For the second case, must make sure timeout
1226 * is not too big, or else we can send
1227 * futile renew requests for hours.
1228 * (Ab)use -A TIMEOUT value (usually 20 sec)
1229 * as a cap on the timeout.
1230 */
1231 if (timeout > tryagain_timeout)
1232 timeout = tryagain_timeout;
1233 goto case_RENEW_REQUESTED;
1234 }
1235 /* Start things over */
1236 packet_num = 0;
1237 /* Kill any timeouts, user wants this to hurry along */
1238 timeout = 0;
1239 continue;
1240 case SIGUSR2:
1241 perform_d6_release(&srv6_buf, requested_ipv6);
1242 timeout = INT_MAX;
1243 continue;
1244 case SIGTERM:
1245 bb_info_msg("Received SIGTERM");
1246 goto ret0;
1247 }
1248
1249 /* Is it a packet? */
1250 if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
1251 continue; /* no */
1252
1253 {
1254 int len;
1255
1256 /* A packet is ready, read it */
1257 if (listen_mode == LISTEN_KERNEL)
1258 len = d6_recv_kernel_packet(&srv6_buf, &packet, sockfd);
1259 else
1260 len = d6_recv_raw_packet(&srv6_buf, &packet, sockfd);
1261 if (len == -1) {
1262 /* Error is severe, reopen socket */
1263 bb_info_msg("Read error: %s, reopening socket", strerror(errno));
1264 sleep(discover_timeout); /* 3 seconds by default */
1265 change_listen_mode(listen_mode); /* just close and reopen */
1266 }
1267 /* If this packet will turn out to be unrelated/bogus,
1268 * we will go back and wait for next one.
1269 * Be sure timeout is properly decreased. */
1270 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1271 if (len < 0)
1272 continue;
1273 packet_end = (uint8_t*)&packet + len;
1274 }
1275
1276 if ((packet.d6_xid32 & htonl(0x00ffffff)) != xid) {
1277 log1("xid %x (our is %x), ignoring packet",
1278 (unsigned)(packet.d6_xid32 & htonl(0x00ffffff)), (unsigned)xid);
1279 continue;
1280 }
1281
1282 switch (state) {
1283 case INIT_SELECTING:
1284 if (packet.d6_msg_type == D6_MSG_ADVERTISE)
1285 goto type_is_ok;
1286 /* DHCPv6 has "Rapid Commit", when instead of Advertise,
1287 * server sends Reply right away.
1288 * Fall through to check for this case.
1289 */
1290 case REQUESTING:
1291 case RENEWING:
1292 case RENEW_REQUESTED:
1293 case REBINDING:
1294 if (packet.d6_msg_type == D6_MSG_REPLY) {
1295 uint32_t lease_seconds;
1296 struct d6_option *option, *iaaddr;
1297 type_is_ok:
1298 option = d6_find_option(packet.d6_options, packet_end, D6_OPT_STATUS_CODE);
1299 if (option && option->data[4] != 0) {
1300 /* return to init state */
1301 bb_info_msg("Received DHCP NAK (%u)", option->data[4]);
1302 d6_run_script(&packet, "nak");
1303 if (state != REQUESTING)
1304 d6_run_script(NULL, "deconfig");
1305 change_listen_mode(LISTEN_RAW);
1306 sleep(3); /* avoid excessive network traffic */
1307 state = INIT_SELECTING;
1308 client_config.first_secs = 0; /* make secs field count from 0 */
1309 requested_ipv6 = NULL;
1310 timeout = 0;
1311 packet_num = 0;
1312 already_waited_sec = 0;
1313 continue;
1314 }
1315 option = d6_copy_option(packet.d6_options, packet_end, D6_OPT_SERVERID);
1316 if (!option) {
1317 bb_error_msg("no server ID, ignoring packet");
1318 continue;
1319 /* still selecting - this server looks bad */
1320 }
1321 //Note: we do not bother comparing server IDs in Advertise and Reply msgs.
1322 //server_id variable is used solely for creation of proper server_id option
1323 //in outgoing packets. (why DHCPv6 even introduced it is a mystery).
1324 free(client6_data.server_id);
1325 client6_data.server_id = option;
1326 if (packet.d6_msg_type == D6_MSG_ADVERTISE) {
1327 /* enter requesting state */
1328 state = REQUESTING;
1329 timeout = 0;
1330 packet_num = 0;
1331 already_waited_sec = 0;
1332 continue;
1333 }
1334 /* It's a D6_MSG_REPLY */
1335 /*
1336 * RFC 3315 18.1.8. Receipt of Reply Messages
1337 *
1338 * Upon the receipt of a valid Reply message in response to a Solicit
1339 * (with a Rapid Commit option), Request, Confirm, Renew, Rebind or
1340 * Information-request message, the client extracts the configuration
1341 * information contained in the Reply. The client MAY choose to report
1342 * any status code or message from the status code option in the Reply
1343 * message.
1344 *
1345 * The client SHOULD perform duplicate address detection [17] on each of
1346 * the addresses in any IAs it receives in the Reply message before
1347 * using that address for traffic. If any of the addresses are found to
1348 * be in use on the link, the client sends a Decline message to the
1349 * server as described in section 18.1.7.
1350 *
1351 * If the Reply was received in response to a Solicit (with a Rapid
1352 * Commit option), Request, Renew or Rebind message, the client updates
1353 * the information it has recorded about IAs from the IA options
1354 * contained in the Reply message:
1355 *
1356 * - Record T1 and T2 times.
1357 *
1358 * - Add any new addresses in the IA option to the IA as recorded by
1359 * the client.
1360 *
1361 * - Update lifetimes for any addresses in the IA option that the
1362 * client already has recorded in the IA.
1363 *
1364 * - Discard any addresses from the IA, as recorded by the client, that
1365 * have a valid lifetime of 0 in the IA Address option.
1366 *
1367 * - Leave unchanged any information about addresses the client has
1368 * recorded in the IA but that were not included in the IA from the
1369 * server.
1370 *
1371 * Management of the specific configuration information is detailed in
1372 * the definition of each option in section 22.
1373 *
1374 * If the client receives a Reply message with a Status Code containing
1375 * UnspecFail, the server is indicating that it was unable to process
1376 * the message due to an unspecified failure condition. If the client
1377 * retransmits the original message to the same server to retry the
1378 * desired operation, the client MUST limit the rate at which it
1379 * retransmits the message and limit the duration of the time during
1380 * which it retransmits the message.
1381 *
1382 * When the client receives a Reply message with a Status Code option
1383 * with the value UseMulticast, the client records the receipt of the
1384 * message and sends subsequent messages to the server through the
1385 * interface on which the message was received using multicast. The
1386 * client resends the original message using multicast.
1387 *
1388 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1389 * | OPTION_IA_NA | option-len |
1390 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1391 * | IAID (4 octets) |
1392 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1393 * | T1 |
1394 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1395 * | T2 |
1396 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1397 * | |
1398 * . IA_NA-options .
1399 * . .
1400 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1401 *
1402 *
1403 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1404 * | OPTION_IAADDR | option-len |
1405 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1406 * | |
1407 * | IPv6 address |
1408 * | |
1409 * | |
1410 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1411 * | preferred-lifetime |
1412 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1413 * | valid-lifetime |
1414 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1415 * . .
1416 * . IAaddr-options .
1417 * . .
1418 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1419 */
1420 free(client6_data.ia_na);
1421 client6_data.ia_na = d6_copy_option(packet.d6_options, packet_end, D6_OPT_IA_NA);
1422 if (!client6_data.ia_na) {
1423 bb_error_msg("no %s option, ignoring packet", "IA_NA");
1424 continue;
1425 }
1426 if (client6_data.ia_na->len < (4 + 4 + 4) + (2 + 2 + 16 + 4 + 4)) {
1427 bb_error_msg("IA_NA option is too short:%d bytes", client6_data.ia_na->len);
1428 continue;
1429 }
1430 iaaddr = d6_find_option(client6_data.ia_na->data + 4 + 4 + 4,
1431 client6_data.ia_na->data + client6_data.ia_na->len,
1432 D6_OPT_IAADDR
1433 );
1434 if (!iaaddr) {
1435 bb_error_msg("no %s option, ignoring packet", "IAADDR");
1436 continue;
1437 }
1438 if (iaaddr->len < (16 + 4 + 4)) {
1439 bb_error_msg("IAADDR option is too short:%d bytes", iaaddr->len);
1440 continue;
1441 }
1442 /* Note: the address is sufficiently aligned for cast:
1443 * we _copied_ IA-NA, and copy is always well-aligned.
1444 */
1445 requested_ipv6 = (struct in6_addr*) iaaddr->data;
1446 move_from_unaligned32(lease_seconds, iaaddr->data + 16 + 4);
1447 lease_seconds = ntohl(lease_seconds);
1448 /* paranoia: must not be too small and not prone to overflows */
1449 if (lease_seconds < 0x10)
1450 lease_seconds = 0x10;
1451 /// TODO: check for 0 lease time?
1452 if (lease_seconds >= 0x10000000)
1453 lease_seconds = 0x0fffffff;
1454 /* enter bound state */
1455 timeout = lease_seconds / 2;
1456 bb_info_msg("Lease obtained, lease time %u",
1457 /*inet_ntoa(temp_addr),*/ (unsigned)lease_seconds);
1458 d6_run_script(&packet, state == REQUESTING ? "bound" : "renew");
1459
1460 state = BOUND;
1461 change_listen_mode(LISTEN_NONE);
1462 if (opt & OPT_q) { /* quit after lease */
1463 goto ret0;
1464 }
1465 /* future renew failures should not exit (JM) */
1466 opt &= ~OPT_n;
1467 #if BB_MMU /* NOMMU case backgrounded earlier */
1468 if (!(opt & OPT_f)) {
1469 client_background();
1470 /* do not background again! */
1471 opt = ((opt & ~OPT_b) | OPT_f);
1472 }
1473 #endif
1474 already_waited_sec = 0;
1475 continue; /* back to main loop */
1476 }
1477 continue;
1478 /* case BOUND: - ignore all packets */
1479 /* case RELEASED: - ignore all packets */
1480 }
1481 /* back to main loop */
1482 } /* for (;;) - main loop ends */
1483
1484 ret0:
1485 if (opt & OPT_R) /* release on quit */
1486 perform_d6_release(&srv6_buf, requested_ipv6);
1487 retval = 0;
1488 ret:
1489 /*if (client_config.pidfile) - remove_pidfile has its own check */
1490 remove_pidfile(client_config.pidfile);
1491 return retval;
1492 }
Tomato firmware and modifications.