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d6_dhcpc.c@ 3621

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Last change on this file since 3621 was 3621, checked in by Bruno Cornec, 7 years ago
New 3?3 banch for incorporation of latest busybox 1.25. Changing minor version to handle potential incompatibilities.
Property svn:eol-style set to `native`
File size: 50.7 KB

Line
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 xmemdup(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_PORT6,
315	/dst/ (struct in6_addr*)FF02__1_2, SERVER_PORT6, 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_error_msg("sending %s", "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_error_msg("sending %s", "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_error_msg("sending %s", "renew");
554	if (server_ipv6)
555	return d6_send_kernel_packet(
556	&packet, (opt_ptr - (uint8_t*) &packet),
557	our_cur_ipv6, CLIENT_PORT6,
558	server_ipv6, SERVER_PORT6
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_error_msg("sending %s", "release");
577	return d6_send_kernel_packet(
578	&packet, (opt_ptr - (uint8_t*) &packet),
579	our_cur_ipv6, CLIENT_PORT6,
580	server_ipv6, SERVER_PORT6
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_PORT6)
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 %s", "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_PORT6, 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, 0x7fffffff),
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_PORT6 == 546) {
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_PORT6, 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_error_msg("performing 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_error_msg("unicasting a release");
798	send_d6_release(server_ipv6, our_cur_ipv6); /* unicast */
799	d6_run_script(NULL, "deconfig");
800	}
801	bb_error_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	setup_common_bufsiz();
934
935	/* Default options */
936	IF_FEATURE_UDHCP_PORT(SERVER_PORT6 = 547;)
937	IF_FEATURE_UDHCP_PORT(CLIENT_PORT6 = 546;)
938	client_config.interface = "eth0";
939	client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
940
941	/* Parse command line */
942	/* O,x: list; -T,-t,-A take numeric param */
943	opt_complementary = "O::x::T+:t+:A+" IF_UDHCP_VERBOSE(":vv") ;
944	IF_LONG_OPTS(applet_long_options = udhcpc6_longopts;)
945	opt = getopt32(argv, "i:np:qRr:s:T:t:SA:O:ox:f"
946	USE_FOR_MMU("b")
947	///IF_FEATURE_UDHCPC_ARPING("a")
948	IF_FEATURE_UDHCP_PORT("P:")
949	"v"
950	, &client_config.interface, &client_config.pidfile, &str_r /* i,p */
951	, &client_config.script /* s */
952	, &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
953	, &list_O
954	, &list_x
955	IF_FEATURE_UDHCP_PORT(, &str_P)
956	IF_UDHCP_VERBOSE(, &dhcp_verbose)
957	);
958	requested_ipv6 = NULL;
959	if (opt & OPT_r) {
960	if (inet_pton(AF_INET6, str_r, &ipv6_buf) <= 0)
961	bb_error_msg_and_die("bad IPv6 address '%s'", str_r);
962	requested_ipv6 = &ipv6_buf;
963	}
964	#if ENABLE_FEATURE_UDHCP_PORT
965	if (opt & OPT_P) {
966	CLIENT_PORT6 = xatou16(str_P);
967	SERVER_PORT6 = CLIENT_PORT6 + 1;
968	}
969	#endif
970	while (list_O) {
971	char *optstr = llist_pop(&list_O);
972	unsigned n = bb_strtou(optstr, NULL, 0);
973	if (errno \|\| n > 254) {
974	n = udhcp_option_idx(optstr);
975	n = dhcp_optflags[n].code;
976	}
977	client_config.opt_mask[n >> 3] \|= 1 << (n & 7);
978	}
979	if (!(opt & OPT_o)) {
980	/*
981	unsigned i, n;
982	for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) {
983	if (dhcp_optflags[i].flags & OPTION_REQ) {
984	client_config.opt_mask[n >> 3] \|= 1 << (n & 7);
985	}
986	}
987	*/
988	}
989	while (list_x) {
990	char *optstr = llist_pop(&list_x);
991	char *colon = strchr(optstr, ':');
992	if (colon)
993	*colon = ' ';
994	/* now it looks similar to udhcpd's config file line:
995	* "optname optval", using the common routine: */
996	udhcp_str2optset(optstr, &client_config.options);
997	}
998
999	if (udhcp_read_interface(client_config.interface,
1000	&client_config.ifindex,
1001	NULL,
1002	client_config.client_mac)
1003	) {
1004	return 1;
1005	}
1006
1007	/* Create client ID based on mac, set clientid_mac_ptr */
1008	{
1009	struct d6_option *clientid;
1010	clientid = xzalloc(2+2+2+2+6);
1011	clientid->code = D6_OPT_CLIENTID;
1012	clientid->len = 2+2+6;
1013	clientid->data[1] = 3; /* DUID-LL */
1014	clientid->data[3] = 1; /* ethernet */
1015	clientid_mac_ptr = clientid->data + 2+2;
1016	memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1017	client_config.clientid = (void*)clientid;
1018	}
1019
1020	#if !BB_MMU
1021	/* on NOMMU reexec (i.e., background) early */
1022	if (!(opt & OPT_f)) {
1023	bb_daemonize_or_rexec(0 /* flags */, argv);
1024	logmode = LOGMODE_NONE;
1025	}
1026	#endif
1027	if (opt & OPT_S) {
1028	openlog(applet_name, LOG_PID, LOG_DAEMON);
1029	logmode \|= LOGMODE_SYSLOG;
1030	}
1031
1032	/* Make sure fd 0,1,2 are open */
1033	bb_sanitize_stdio();
1034	/* Equivalent of doing a fflush after every \n */
1035	setlinebuf(stdout);
1036	/* Create pidfile */
1037	write_pidfile(client_config.pidfile);
1038	/* Goes to stdout (unless NOMMU) and possibly syslog */
1039	bb_error_msg("started, v"BB_VER);
1040	/* Set up the signal pipe */
1041	udhcp_sp_setup();
1042	/* We want random_xid to be random... */
1043	srand(monotonic_us());
1044
1045	state = INIT_SELECTING;
1046	d6_run_script(NULL, "deconfig");
1047	change_listen_mode(LISTEN_RAW);
1048	packet_num = 0;
1049	timeout = 0;
1050	already_waited_sec = 0;
1051
1052	/* Main event loop. select() waits on signal pipe and possibly
1053	* on sockfd.
1054	* "continue" statements in code below jump to the top of the loop.
1055	*/
1056	for (;;) {
1057	struct timeval tv;
1058	struct d6_packet packet;
1059	uint8_t *packet_end;
1060	/* silence "uninitialized!" warning */
1061	unsigned timestamp_before_wait = timestamp_before_wait;
1062
1063	//bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
1064
1065	/* Was opening raw or udp socket here
1066	* if (listen_mode != LISTEN_NONE && sockfd < 0),
1067	* but on fast network renew responses return faster
1068	* than we open sockets. Thus this code is moved
1069	* to change_listen_mode(). Thus we open listen socket
1070	* BEFORE we send renew request (see "case BOUND:"). */
1071
1072	max_fd = udhcp_sp_fd_set(&rfds, sockfd);
1073
1074	tv.tv_sec = timeout - already_waited_sec;
1075	tv.tv_usec = 0;
1076	retval = 0;
1077	/* If we already timed out, fall through with retval = 0, else... */
1078	if ((int)tv.tv_sec > 0) {
1079	log1("waiting on select %u seconds", (int)tv.tv_sec);
1080	timestamp_before_wait = (unsigned)monotonic_sec();
1081	retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
1082	if (retval < 0) {
1083	/* EINTR? A signal was caught, don't panic */
1084	if (errno == EINTR) {
1085	already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1086	continue;
1087	}
1088	/* Else: an error occured, panic! */
1089	bb_perror_msg_and_die("select");
1090	}
1091	}
1092
1093	/* If timeout dropped to zero, time to become active:
1094	* resend discover/renew/whatever
1095	*/
1096	if (retval == 0) {
1097	/* When running on a bridge, the ifindex may have changed
1098	* (e.g. if member interfaces were added/removed
1099	* or if the status of the bridge changed).
1100	* Refresh ifindex and client_mac:
1101	*/
1102	if (udhcp_read_interface(client_config.interface,
1103	&client_config.ifindex,
1104	NULL,
1105	client_config.client_mac)
1106	) {
1107	goto ret0; /* iface is gone? */
1108	}
1109	memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1110
1111	/* We will restart the wait in any case */
1112	already_waited_sec = 0;
1113
1114	switch (state) {
1115	case INIT_SELECTING:
1116	if (!discover_retries \|\| packet_num < discover_retries) {
1117	if (packet_num == 0)
1118	xid = random_xid();
1119	/* multicast */
1120	send_d6_discover(xid, requested_ipv6);
1121	timeout = discover_timeout;
1122	packet_num++;
1123	continue;
1124	}
1125	leasefail:
1126	d6_run_script(NULL, "leasefail");
1127	#if BB_MMU /* -b is not supported on NOMMU */
1128	if (opt & OPT_b) { /* background if no lease */
1129	bb_error_msg("no lease, forking to background");
1130	client_background();
1131	/* do not background again! */
1132	opt = ((opt & ~OPT_b) \| OPT_f);
1133	} else
1134	#endif
1135	if (opt & OPT_n) { /* abort if no lease */
1136	bb_error_msg("no lease, failing");
1137	retval = 1;
1138	goto ret;
1139	}
1140	/* wait before trying again */
1141	timeout = tryagain_timeout;
1142	packet_num = 0;
1143	continue;
1144	case REQUESTING:
1145	if (!discover_retries \|\| packet_num < discover_retries) {
1146	/* send multicast select packet */
1147	send_d6_select(xid);
1148	timeout = discover_timeout;
1149	packet_num++;
1150	continue;
1151	}
1152	/* Timed out, go back to init state.
1153	* "discover...select...discover..." loops
1154	* were seen in the wild. Treat them similarly
1155	* to "no response to discover" case */
1156	change_listen_mode(LISTEN_RAW);
1157	state = INIT_SELECTING;
1158	goto leasefail;
1159	case BOUND:
1160	/* 1/2 lease passed, enter renewing state */
1161	state = RENEWING;
1162	client_config.first_secs = 0; /* make secs field count from 0 */
1163	change_listen_mode(LISTEN_KERNEL);
1164	log1("entering renew state");
1165	/* fall right through */
1166	case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
1167	case_RENEW_REQUESTED:
1168	case RENEWING:
1169	if (timeout > 60) {
1170	/* send an unicast renew request */
1171	/* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1172	* a new UDP socket for sending inside send_renew.
1173	* I hazard to guess existing listening socket
1174	* is somehow conflicting with it, but why is it
1175	* not deterministic then?! Strange.
1176	* Anyway, it does recover by eventually failing through
1177	* into INIT_SELECTING state.
1178	*/
1179	send_d6_renew(xid, &srv6_buf, requested_ipv6);
1180	timeout >>= 1;
1181	continue;
1182	}
1183	/* Timed out, enter rebinding state */
1184	log1("entering rebinding state");
1185	state = REBINDING;
1186	/* fall right through */
1187	case REBINDING:
1188	/* Switch to bcast receive */
1189	change_listen_mode(LISTEN_RAW);
1190	/* Lease is really about to run out,
1191	* try to find DHCP server using broadcast */
1192	if (timeout > 0) {
1193	/* send a broadcast renew request */
1194	send_d6_renew(xid, /server_ipv6:/ NULL, requested_ipv6);
1195	timeout >>= 1;
1196	continue;
1197	}
1198	/* Timed out, enter init state */
1199	bb_error_msg("lease lost, entering init state");
1200	d6_run_script(NULL, "deconfig");
1201	state = INIT_SELECTING;
1202	client_config.first_secs = 0; /* make secs field count from 0 */
1203	/timeout = 0; - already is /
1204	packet_num = 0;
1205	continue;
1206	/* case RELEASED: */
1207	}
1208	/* yah, I know, you say it would never happen */
1209	timeout = INT_MAX;
1210	continue; /* back to main loop */
1211	} /* if select timed out */
1212
1213	/* select() didn't timeout, something happened */
1214
1215	/* Is it a signal? */
1216	/* note: udhcp_sp_read checks FD_ISSET before reading */
1217	switch (udhcp_sp_read(&rfds)) {
1218	case SIGUSR1:
1219	client_config.first_secs = 0; /* make secs field count from 0 */
1220	already_waited_sec = 0;
1221	perform_renew();
1222	if (state == RENEW_REQUESTED) {
1223	/* We might be either on the same network
1224	* (in which case renew might work),
1225	* or we might be on a completely different one
1226	* (in which case renew won't ever succeed).
1227	* For the second case, must make sure timeout
1228	* is not too big, or else we can send
1229	* futile renew requests for hours.
1230	* (Ab)use -A TIMEOUT value (usually 20 sec)
1231	* as a cap on the timeout.
1232	*/
1233	if (timeout > tryagain_timeout)
1234	timeout = tryagain_timeout;
1235	goto case_RENEW_REQUESTED;
1236	}
1237	/* Start things over */
1238	packet_num = 0;
1239	/* Kill any timeouts, user wants this to hurry along */
1240	timeout = 0;
1241	continue;
1242	case SIGUSR2:
1243	perform_d6_release(&srv6_buf, requested_ipv6);
1244	timeout = INT_MAX;
1245	continue;
1246	case SIGTERM:
1247	bb_error_msg("received %s", "SIGTERM");
1248	goto ret0;
1249	}
1250
1251	/* Is it a packet? */
1252	if (listen_mode == LISTEN_NONE \|\| !FD_ISSET(sockfd, &rfds))
1253	continue; /* no */
1254
1255	{
1256	int len;
1257
1258	/* A packet is ready, read it */
1259	if (listen_mode == LISTEN_KERNEL)
1260	len = d6_recv_kernel_packet(&srv6_buf, &packet, sockfd);
1261	else
1262	len = d6_recv_raw_packet(&srv6_buf, &packet, sockfd);
1263	if (len == -1) {
1264	/* Error is severe, reopen socket */
1265	bb_error_msg("read error: %s, reopening socket", strerror(errno));
1266	sleep(discover_timeout); /* 3 seconds by default */
1267	change_listen_mode(listen_mode); /* just close and reopen */
1268	}
1269	/* If this packet will turn out to be unrelated/bogus,
1270	* we will go back and wait for next one.
1271	* Be sure timeout is properly decreased. */
1272	already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1273	if (len < 0)
1274	continue;
1275	packet_end = (uint8_t*)&packet + len;
1276	}
1277
1278	if ((packet.d6_xid32 & htonl(0x00ffffff)) != xid) {
1279	log1("xid %x (our is %x), ignoring packet",
1280	(unsigned)(packet.d6_xid32 & htonl(0x00ffffff)), (unsigned)xid);
1281	continue;
1282	}
1283
1284	switch (state) {
1285	case INIT_SELECTING:
1286	if (packet.d6_msg_type == D6_MSG_ADVERTISE)
1287	goto type_is_ok;
1288	/* DHCPv6 has "Rapid Commit", when instead of Advertise,
1289	* server sends Reply right away.
1290	* Fall through to check for this case.
1291	*/
1292	case REQUESTING:
1293	case RENEWING:
1294	case RENEW_REQUESTED:
1295	case REBINDING:
1296	if (packet.d6_msg_type == D6_MSG_REPLY) {
1297	uint32_t lease_seconds;
1298	struct d6_option option, iaaddr;
1299	type_is_ok:
1300	option = d6_find_option(packet.d6_options, packet_end, D6_OPT_STATUS_CODE);
1301	if (option && option->data[4] != 0) {
1302	/* return to init state */
1303	bb_error_msg("received DHCP NAK (%u)", option->data[4]);
1304	d6_run_script(&packet, "nak");
1305	if (state != REQUESTING)
1306	d6_run_script(NULL, "deconfig");
1307	change_listen_mode(LISTEN_RAW);
1308	sleep(3); /* avoid excessive network traffic */
1309	state = INIT_SELECTING;
1310	client_config.first_secs = 0; /* make secs field count from 0 */
1311	requested_ipv6 = NULL;
1312	timeout = 0;
1313	packet_num = 0;
1314	already_waited_sec = 0;
1315	continue;
1316	}
1317	option = d6_copy_option(packet.d6_options, packet_end, D6_OPT_SERVERID);
1318	if (!option) {
1319	bb_error_msg("no server ID, ignoring packet");
1320	continue;
1321	/* still selecting - this server looks bad */
1322	}
1323	//Note: we do not bother comparing server IDs in Advertise and Reply msgs.
1324	//server_id variable is used solely for creation of proper server_id option
1325	//in outgoing packets. (why DHCPv6 even introduced it is a mystery).
1326	free(client6_data.server_id);
1327	client6_data.server_id = option;
1328	if (packet.d6_msg_type == D6_MSG_ADVERTISE) {
1329	/* enter requesting state */
1330	state = REQUESTING;
1331	timeout = 0;
1332	packet_num = 0;
1333	already_waited_sec = 0;
1334	continue;
1335	}
1336	/* It's a D6_MSG_REPLY */
1337	/*
1338	* RFC 3315 18.1.8. Receipt of Reply Messages
1339	*
1340	* Upon the receipt of a valid Reply message in response to a Solicit
1341	* (with a Rapid Commit option), Request, Confirm, Renew, Rebind or
1342	* Information-request message, the client extracts the configuration
1343	* information contained in the Reply. The client MAY choose to report
1344	* any status code or message from the status code option in the Reply
1345	* message.
1346	*
1347	* The client SHOULD perform duplicate address detection [17] on each of
1348	* the addresses in any IAs it receives in the Reply message before
1349	* using that address for traffic. If any of the addresses are found to
1350	* be in use on the link, the client sends a Decline message to the
1351	* server as described in section 18.1.7.
1352	*
1353	* If the Reply was received in response to a Solicit (with a Rapid
1354	* Commit option), Request, Renew or Rebind message, the client updates
1355	* the information it has recorded about IAs from the IA options
1356	* contained in the Reply message:
1357	*
1358	* - Record T1 and T2 times.
1359	*
1360	* - Add any new addresses in the IA option to the IA as recorded by
1361	* the client.
1362	*
1363	* - Update lifetimes for any addresses in the IA option that the
1364	* client already has recorded in the IA.
1365	*
1366	* - Discard any addresses from the IA, as recorded by the client, that
1367	* have a valid lifetime of 0 in the IA Address option.
1368	*
1369	* - Leave unchanged any information about addresses the client has
1370	* recorded in the IA but that were not included in the IA from the
1371	* server.
1372	*
1373	* Management of the specific configuration information is detailed in
1374	* the definition of each option in section 22.
1375	*
1376	* If the client receives a Reply message with a Status Code containing
1377	* UnspecFail, the server is indicating that it was unable to process
1378	* the message due to an unspecified failure condition. If the client
1379	* retransmits the original message to the same server to retry the
1380	* desired operation, the client MUST limit the rate at which it
1381	* retransmits the message and limit the duration of the time during
1382	* which it retransmits the message.
1383	*
1384	* When the client receives a Reply message with a Status Code option
1385	* with the value UseMulticast, the client records the receipt of the
1386	* message and sends subsequent messages to the server through the
1387	* interface on which the message was received using multicast. The
1388	* client resends the original message using multicast.
1389	*
1390	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1391	* \| OPTION_IA_NA \| option-len \|
1392	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1393	* \| IAID (4 octets) \|
1394	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1395	* \| T1 \|
1396	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1397	* \| T2 \|
1398	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1399	* \| \|
1400	* . IA_NA-options .
1401	* . .
1402	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1403	*
1404	*
1405	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1406	* \| OPTION_IAADDR \| option-len \|
1407	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1408	* \| \|
1409	* \| IPv6 address \|
1410	* \| \|
1411	* \| \|
1412	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1413	* \| preferred-lifetime \|
1414	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1415	* \| valid-lifetime \|
1416	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1417	* . .
1418	* . IAaddr-options .
1419	* . .
1420	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1421	*/
1422	free(client6_data.ia_na);
1423	client6_data.ia_na = d6_copy_option(packet.d6_options, packet_end, D6_OPT_IA_NA);
1424	if (!client6_data.ia_na) {
1425	bb_error_msg("no %s option, ignoring packet", "IA_NA");
1426	continue;
1427	}
1428	if (client6_data.ia_na->len < (4 + 4 + 4) + (2 + 2 + 16 + 4 + 4)) {
1429	bb_error_msg("IA_NA option is too short:%d bytes", client6_data.ia_na->len);
1430	continue;
1431	}
1432	iaaddr = d6_find_option(client6_data.ia_na->data + 4 + 4 + 4,
1433	client6_data.ia_na->data + client6_data.ia_na->len,
1434	D6_OPT_IAADDR
1435	);
1436	if (!iaaddr) {
1437	bb_error_msg("no %s option, ignoring packet", "IAADDR");
1438	continue;
1439	}
1440	if (iaaddr->len < (16 + 4 + 4)) {
1441	bb_error_msg("IAADDR option is too short:%d bytes", iaaddr->len);
1442	continue;
1443	}
1444	/* Note: the address is sufficiently aligned for cast:
1445	* we _copied_ IA-NA, and copy is always well-aligned.
1446	*/
1447	requested_ipv6 = (struct in6_addr*) iaaddr->data;
1448	move_from_unaligned32(lease_seconds, iaaddr->data + 16 + 4);
1449	lease_seconds = ntohl(lease_seconds);
1450	/* paranoia: must not be too small and not prone to overflows */
1451	if (lease_seconds < 0x10)
1452	lease_seconds = 0x10;
1453	/// TODO: check for 0 lease time?
1454	if (lease_seconds >= 0x10000000)
1455	lease_seconds = 0x0fffffff;
1456	/* enter bound state */
1457	timeout = lease_seconds / 2;
1458	bb_error_msg("lease obtained, lease time %u",
1459	/inet_ntoa(temp_addr),/ (unsigned)lease_seconds);
1460	d6_run_script(&packet, state == REQUESTING ? "bound" : "renew");
1461
1462	state = BOUND;
1463	change_listen_mode(LISTEN_NONE);
1464	if (opt & OPT_q) { /* quit after lease */
1465	goto ret0;
1466	}
1467	/* future renew failures should not exit (JM) */
1468	opt &= ~OPT_n;
1469	#if BB_MMU /* NOMMU case backgrounded earlier */
1470	if (!(opt & OPT_f)) {
1471	client_background();
1472	/* do not background again! */
1473	opt = ((opt & ~OPT_b) \| OPT_f);
1474	}
1475	#endif
1476	already_waited_sec = 0;
1477	continue; /* back to main loop */
1478	}
1479	continue;
1480	/* case BOUND: - ignore all packets */
1481	/* case RELEASED: - ignore all packets */
1482	}
1483	/* back to main loop */
1484	} /* for (;;) - main loop ends */
1485
1486	ret0:
1487	if (opt & OPT_R) /* release on quit */
1488	perform_d6_release(&srv6_buf, requested_ipv6);
1489	retval = 0;
1490	ret:
1491	/if (client_config.pidfile) - remove_pidfile has its own check /
1492	remove_pidfile(client_config.pidfile);
1493	return retval;
1494	}

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source: MondoRescue/branches/3.3/mindi-busybox/networking/udhcp/d6_dhcpc.c@ 3621

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