1 /* vi: set sw=4 ts=4: */
5 * WARNING: THIS CODE IS INCOMPLETE.
7 * Copyright (C) 2011-2017 Denys Vlasenko.
9 * Licensed under GPLv2, see file LICENSE in this source tree.
12 //config:config UDHCPC6
13 //config: bool "udhcpc6 (DHCPv6 client, EXPERIMENTAL)"
14 //config: default n # not yet ready
15 //config: depends on FEATURE_IPV6
17 //config: udhcpc6 is a DHCPv6 client
19 //config:config FEATURE_UDHCPC6_RFC3646
20 //config: bool "Support RFC 3646 (DNS server and search list)"
22 //config: depends on UDHCPC6
24 //config: List of DNS servers and domain search list can be requested with
25 //config: "-O dns" and "-O search". If server gives these values,
26 //config: they will be set in environment variables "dns" and "search".
28 //config:config FEATURE_UDHCPC6_RFC4704
29 //config: bool "Support RFC 4704 (Client FQDN)"
31 //config: depends on UDHCPC6
33 //config: You can request FQDN to be given by server using "-O fqdn".
35 //config:config FEATURE_UDHCPC6_RFC4833
36 //config: bool "Support RFC 4833 (Timezones)"
38 //config: depends on UDHCPC6
40 //config: You can request POSIX timezone with "-O tz" and timezone name
41 //config: with "-O timezone".
43 //applet:IF_UDHCPC6(APPLET(udhcpc6, BB_DIR_USR_BIN, BB_SUID_DROP))
45 //kbuild:lib-$(CONFIG_UDHCPC6) += d6_dhcpc.o d6_packet.o d6_socket.o common.o socket.o signalpipe.o
46 //kbuild:lib-$(CONFIG_FEATURE_UDHCPC6_RFC3646) += domain_codec.o
47 //kbuild:lib-$(CONFIG_FEATURE_UDHCPC6_RFC4704) += domain_codec.o
50 /* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
51 #define WANT_PIDFILE 1
55 #include "d6_common.h"
57 #include <netinet/if_ether.h>
58 #include <netpacket/packet.h>
59 #include <linux/filter.h>
61 /* "struct client_config_t client_config" is in bb_common_bufsiz1 */
63 static const struct dhcp_optflag d6_optflags[] = {
64 #if ENABLE_FEATURE_UDHCPC6_RFC3646
65 { OPTION_6RD | OPTION_LIST | OPTION_REQ, D6_OPT_DNS_SERVERS },
66 { OPTION_DNS_STRING | OPTION_LIST | OPTION_REQ, D6_OPT_DOMAIN_LIST },
68 #if ENABLE_FEATURE_UDHCPC6_RFC4704
69 { OPTION_DNS_STRING, D6_OPT_CLIENT_FQDN },
71 #if ENABLE_FEATURE_UDHCPC6_RFC4833
72 { OPTION_STRING, D6_OPT_TZ_POSIX },
73 { OPTION_STRING, D6_OPT_TZ_NAME },
77 /* Must match d6_optflags[] order */
78 static const char d6_option_strings[] ALIGN1 =
79 #if ENABLE_FEATURE_UDHCPC6_RFC3646
80 "dns" "\0" /* D6_OPT_DNS_SERVERS */
81 "search" "\0" /* D6_OPT_DOMAIN_LIST */
83 #if ENABLE_FEATURE_UDHCPC6_RFC4704
84 "fqdn" "\0" /* D6_OPT_CLIENT_FQDN */
86 #if ENABLE_FEATURE_UDHCPC6_RFC4833
87 "tz" "\0" /* D6_OPT_TZ_POSIX */
88 "timezone" "\0" /* D6_OPT_TZ_NAME */
93 static const char udhcpc6_longopts[] ALIGN1 =
94 "interface\0" Required_argument "i"
95 "now\0" No_argument "n"
96 "pidfile\0" Required_argument "p"
97 "quit\0" No_argument "q"
98 "release\0" No_argument "R"
99 "request\0" Required_argument "r"
100 "script\0" Required_argument "s"
101 "timeout\0" Required_argument "T"
102 "retries\0" Required_argument "t"
103 "tryagain\0" Required_argument "A"
104 "syslog\0" No_argument "S"
105 "request-option\0" Required_argument "O"
106 "no-default-options\0" No_argument "o"
107 "foreground\0" No_argument "f"
109 "background\0" No_argument "b"
111 /// IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
112 IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
115 /* Must match getopt32 option string order */
132 /* The rest has variable bit positions, need to be clever */
134 USE_FOR_MMU( OPTBIT_b,)
135 ///IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
136 IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
137 USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
138 ///IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
139 IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
142 #if ENABLE_FEATURE_UDHCPC6_RFC4704
143 static const char opt_fqdn_req[] = {
144 (D6_OPT_CLIENT_FQDN >> 8), (D6_OPT_CLIENT_FQDN & 0xff),
147 /* S=0: server SHOULD NOT perform AAAA RR updates */
148 /* O=0: client MUST set this bit to 0 */
149 /* N=0: server SHOULD perform updates (PTR RR only in our case, since S=0) */
150 0 /* empty DNS-encoded name */
154 /*** Utility functions ***/
156 static void *d6_find_option(uint8_t *option, uint8_t *option_end, unsigned code)
158 /* "length minus 4" */
159 int len_m4 = option_end - option - 4;
160 while (len_m4 >= 0) {
161 /* Next option's len is too big? */
162 if (option[3] > len_m4)
163 return NULL; /* yes. bogus packet! */
164 /* So far we treat any opts with code >255
165 * or len >255 as bogus, and stop at once.
166 * This simplifies big-endian handling.
168 if (option[0] != 0 || option[2] != 0)
170 /* Option seems to be valid */
171 /* Does its code match? */
172 if (option[1] == code)
173 return option; /* yes! */
174 len_m4 -= option[3] + 4;
175 option += option[3] + 4;
180 static void *d6_copy_option(uint8_t *option, uint8_t *option_end, unsigned code)
182 uint8_t *opt = d6_find_option(option, option_end, code);
185 return xmemdup(opt, opt[3] + 4);
189 /*** Script execution code ***/
191 static char** new_env(void)
193 client6_data.env_ptr = xrealloc_vector(client6_data.env_ptr, 3, client6_data.env_idx);
194 return &client6_data.env_ptr[client6_data.env_idx++];
197 /* put all the parameters into the environment */
198 static void option_to_env(uint8_t *option, uint8_t *option_end)
200 #if ENABLE_FEATURE_UDHCPC6_RFC3646
201 int addrs, option_offset;
203 /* "length minus 4" */
204 int len_m4 = option_end - option - 4;
206 while (len_m4 >= 0) {
208 char ipv6str[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")];
210 if (option[0] != 0 || option[2] != 0)
213 /* Check if option-length exceeds size of option */
214 if (option[3] > len_m4)
218 //case D6_OPT_CLIENTID:
219 //case D6_OPT_SERVERID:
222 option_to_env(option + 16, option + 4 + option[3]);
227 * 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
228 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
229 * | OPTION_IAADDR | option-len |
230 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
235 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
236 * | preferred-lifetime |
237 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
239 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
241 sprint_nip6(ipv6str, option + 4);
242 *new_env() = xasprintf("ipv6=%s", ipv6str);
244 move_from_unaligned32(v32, option + 4 + 16 + 4);
245 *new_env() = xasprintf("lease=%u", (unsigned)v32);
249 //case D6_OPT_PREFERENCE:
250 //case D6_OPT_ELAPSED_TIME:
251 //case D6_OPT_RELAY_MSG:
253 //case D6_OPT_UNICAST:
254 //case D6_OPT_STATUS_CODE:
255 //case D6_OPT_RAPID_COMMIT:
256 //case D6_OPT_USER_CLASS:
257 //case D6_OPT_VENDOR_CLASS:
258 //case D6_OPT_VENDOR_OPTS:
259 //case D6_OPT_INTERFACE_ID:
260 //case D6_OPT_RECONF_MSG:
261 //case D6_OPT_RECONF_ACCEPT:
263 case D6_OPT_IAPREFIX:
265 * 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
266 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
267 * | OPTION_IAPREFIX | option-length |
268 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
269 * | preferred-lifetime |
270 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
272 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
273 * | prefix-length | |
274 * +-+-+-+-+-+-+-+-+ IPv6 prefix |
277 * | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
281 //move_from_unaligned32(v32, option + 4 + 4);
282 //*new_env() = xasprintf("lease=%u", (unsigned)v32);
284 sprint_nip6(ipv6str, option + 4 + 4 + 1);
285 *new_env() = xasprintf("ipv6prefix=%s/%u", ipv6str, (unsigned)(option[4 + 4]));
287 #if ENABLE_FEATURE_UDHCPC6_RFC3646
288 case D6_OPT_DNS_SERVERS: {
291 /* Make sure payload-size is a multiple of 16 */
292 if ((option[3] & 0x0f) != 0)
295 /* Get the number of addresses on the option */
296 addrs = option[3] >> 4;
298 /* Setup environment variable */
299 *new_env() = dlist = xmalloc(4 + addrs * 40 - 1);
300 dlist = stpcpy(dlist, "dns=");
304 sprint_nip6(dlist, option + 4 + option_offset);
313 case D6_OPT_DOMAIN_LIST: {
316 dlist = dname_dec(option + 4, (option[2] << 8) | option[3], "search=");
323 #if ENABLE_FEATURE_UDHCPC6_RFC4704
324 case D6_OPT_CLIENT_FQDN: {
329 /* Work around broken ISC DHCPD6.
330 * ISC DHCPD6 does not implement RFC 4704 correctly: It says the first
331 * byte of option-payload should contain flags where the bits 7-3 are
332 * reserved for future use and MUST be zero. Instead ISC DHCPD6 just
333 * writes the entire FQDN as string to option-payload. We assume a
334 * broken server here if any of the reserved bits are set.
336 if (option[4] & 0xf8) {
337 *new_env() = xasprintf("fqdn=%.*s", (int)option[3], (char*)option + 4);
340 dlist = dname_dec(option + 5, (/*(option[2] << 8) |*/ option[3]) - 1, "fqdn=");
347 #if ENABLE_FEATURE_UDHCPC6_RFC4833
348 /* RFC 4833 Timezones */
349 case D6_OPT_TZ_POSIX:
350 *new_env() = xasprintf("tz=%.*s", (int)option[3], (char*)option + 4);
353 *new_env() = xasprintf("tz_name=%.*s", (int)option[3], (char*)option + 4);
357 len_m4 -= 4 + option[3];
358 option += 4 + option[3];
362 static char **fill_envp(struct d6_packet *packet)
366 client6_data.env_ptr = NULL;
367 client6_data.env_idx = 0;
369 *new_env() = xasprintf("interface=%s", client_config.interface);
372 option_to_env(packet->d6_options, packet->d6_options + sizeof(packet->d6_options));
374 envp = curr = client6_data.env_ptr;
381 /* Call a script with a par file and env vars */
382 static void d6_run_script(struct d6_packet *packet, const char *name)
387 envp = fill_envp(packet);
390 log1("executing %s %s", client_config.script, name);
391 argv[0] = (char*) client_config.script;
392 argv[1] = (char*) name;
394 spawn_and_wait(argv);
396 for (curr = envp; *curr; curr++) {
398 bb_unsetenv_and_free(*curr);
404 /*** Sending/receiving packets ***/
406 static ALWAYS_INLINE uint32_t random_xid(void)
408 uint32_t t = rand() & htonl(0x00ffffff);
412 /* Initialize the packet with the proper defaults */
413 static uint8_t *init_d6_packet(struct d6_packet *packet, char type, uint32_t xid)
415 struct d6_option *clientid;
417 memset(packet, 0, sizeof(*packet));
419 packet->d6_xid32 = xid;
420 packet->d6_msg_type = type;
422 clientid = (void*)client_config.clientid;
423 return mempcpy(packet->d6_options, clientid, clientid->len + 2+2);
426 static uint8_t *add_d6_client_options(uint8_t *ptr)
428 uint8_t *start = ptr;
432 for (option = 1; option < 256; option++) {
433 if (client_config.opt_mask[option >> 3] & (1 << (option & 7))) {
434 ptr[0] = (option >> 8);
440 if ((ptr - start - 4) != 0) {
441 start[0] = (D6_OPT_ORO >> 8);
442 start[1] = D6_OPT_ORO;
443 start[2] = ((ptr - start - 4) >> 8);
444 start[3] = (ptr - start - 4);
448 #if ENABLE_FEATURE_UDHCPC6_RFC4704
449 ptr = mempcpy(ptr, &opt_fqdn_req, sizeof(opt_fqdn_req));
451 /* Add -x options if any */
457 static int d6_mcast_from_client_config_ifindex(struct d6_packet *packet, uint8_t *end)
459 static const uint8_t FF02__1_2[16] = {
460 0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
461 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02,
464 return d6_send_raw_packet(
465 packet, (end - (uint8_t*) packet),
466 /*src*/ &client6_data.ll_ip6, CLIENT_PORT6,
467 /*dst*/ (struct in6_addr*)FF02__1_2, SERVER_PORT6, MAC_BCAST_ADDR,
468 client_config.ifindex
472 /* Milticast a DHCPv6 Solicit packet to the network, with an optionally requested IP.
474 * RFC 3315 17.1.1. Creation of Solicit Messages
476 * The client MUST include a Client Identifier option to identify itself
477 * to the server. The client includes IA options for any IAs to which
478 * it wants the server to assign addresses. The client MAY include
479 * addresses in the IAs as a hint to the server about addresses for
480 * which the client has a preference. ...
482 * The client uses IA_NA options to request the assignment of non-
483 * temporary addresses and uses IA_TA options to request the assignment
484 * of temporary addresses. Either IA_NA or IA_TA options, or a
485 * combination of both, can be included in DHCP messages.
487 * The client SHOULD include an Option Request option (see section 22.7)
488 * to indicate the options the client is interested in receiving. The
489 * client MAY additionally include instances of those options that are
490 * identified in the Option Request option, with data values as hints to
491 * the server about parameter values the client would like to have
494 * The client includes a Reconfigure Accept option (see section 22.20)
495 * if the client is willing to accept Reconfigure messages from the
497 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
498 | OPTION_CLIENTID | option-len |
499 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
502 . (variable length) .
504 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
507 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
508 | OPTION_IA_NA | option-len |
509 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
511 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
513 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
515 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
519 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
522 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
523 | OPTION_IAADDR | option-len |
524 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
529 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
530 | preferred-lifetime |
531 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
533 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
540 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
541 | OPTION_ORO | option-len |
542 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
543 | requested-option-code-1 | requested-option-code-2 |
544 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
546 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
549 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
550 | OPTION_RECONF_ACCEPT | 0 |
551 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
553 /* NOINLINE: limit stack usage in caller */
554 static NOINLINE int send_d6_discover(uint32_t xid, struct in6_addr *requested_ipv6)
556 struct d6_packet packet;
560 /* Fill in: msg type, client id */
561 opt_ptr = init_d6_packet(&packet, D6_MSG_SOLICIT, xid);
563 /* Create new IA_NA, optionally with included IAADDR with requested IP */
564 free(client6_data.ia_na);
565 len = requested_ipv6 ? 2+2+4+4+4 + 2+2+16+4+4 : 2+2+4+4+4;
566 client6_data.ia_na = xzalloc(len);
567 client6_data.ia_na->code = D6_OPT_IA_NA;
568 client6_data.ia_na->len = len - 4;
569 *(uint32_t*)client6_data.ia_na->data = rand(); /* IAID */
570 if (requested_ipv6) {
571 struct d6_option *iaaddr = (void*)(client6_data.ia_na->data + 4+4+4);
572 iaaddr->code = D6_OPT_IAADDR;
573 iaaddr->len = 16+4+4;
574 memcpy(iaaddr->data, requested_ipv6, 16);
576 opt_ptr = mempcpy(opt_ptr, client6_data.ia_na, len);
579 * "param req" option according to -O, options specified with -x
581 opt_ptr = add_d6_client_options(opt_ptr);
583 bb_error_msg("sending %s", "discover");
584 return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
587 /* Multicast a DHCPv6 request message
589 * RFC 3315 18.1.1. Creation and Transmission of Request Messages
591 * The client uses a Request message to populate IAs with addresses and
592 * obtain other configuration information. The client includes one or
593 * more IA options in the Request message. The server then returns
594 * addresses and other information about the IAs to the client in IA
595 * options in a Reply message.
597 * The client generates a transaction ID and inserts this value in the
598 * "transaction-id" field.
600 * The client places the identifier of the destination server in a
601 * Server Identifier option.
603 * The client MUST include a Client Identifier option to identify itself
604 * to the server. The client adds any other appropriate options,
605 * including one or more IA options (if the client is requesting that
606 * the server assign it some network addresses).
608 * The client MUST include an Option Request option (see section 22.7)
609 * to indicate the options the client is interested in receiving. The
610 * client MAY include options with data values as hints to the server
611 * about parameter values the client would like to have returned.
613 * The client includes a Reconfigure Accept option (see section 22.20)
614 * indicating whether or not the client is willing to accept Reconfigure
615 * messages from the server.
617 /* NOINLINE: limit stack usage in caller */
618 static NOINLINE int send_d6_select(uint32_t xid)
620 struct d6_packet packet;
623 /* Fill in: msg type, client id */
624 opt_ptr = init_d6_packet(&packet, D6_MSG_REQUEST, xid);
627 opt_ptr = mempcpy(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
628 /* IA NA (contains requested IP) */
629 opt_ptr = mempcpy(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
632 * "param req" option according to -O, options specified with -x
634 opt_ptr = add_d6_client_options(opt_ptr);
636 bb_error_msg("sending %s", "select");
637 return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
640 /* Unicast or broadcast a DHCP renew message
642 * RFC 3315 18.1.3. Creation and Transmission of Renew Messages
644 * To extend the valid and preferred lifetimes for the addresses
645 * associated with an IA, the client sends a Renew message to the server
646 * from which the client obtained the addresses in the IA containing an
647 * IA option for the IA. The client includes IA Address options in the
648 * IA option for the addresses associated with the IA. The server
649 * determines new lifetimes for the addresses in the IA according to the
650 * administrative configuration of the server. The server may also add
651 * new addresses to the IA. The server may remove addresses from the IA
652 * by setting the preferred and valid lifetimes of those addresses to
655 * The server controls the time at which the client contacts the server
656 * to extend the lifetimes on assigned addresses through the T1 and T2
657 * parameters assigned to an IA.
659 * At time T1 for an IA, the client initiates a Renew/Reply message
660 * exchange to extend the lifetimes on any addresses in the IA. The
661 * client includes an IA option with all addresses currently assigned to
662 * the IA in its Renew message.
664 * If T1 or T2 is set to 0 by the server (for an IA_NA) or there are no
665 * T1 or T2 times (for an IA_TA), the client may send a Renew or Rebind
666 * message, respectively, at the client's discretion.
668 * The client sets the "msg-type" field to RENEW. The client generates
669 * a transaction ID and inserts this value in the "transaction-id"
672 * The client places the identifier of the destination server in a
673 * Server Identifier option.
675 * The client MUST include a Client Identifier option to identify itself
676 * to the server. The client adds any appropriate options, including
677 * one or more IA options. The client MUST include the list of
678 * addresses the client currently has associated with the IAs in the
681 * The client MUST include an Option Request option (see section 22.7)
682 * to indicate the options the client is interested in receiving. The
683 * client MAY include options with data values as hints to the server
684 * about parameter values the client would like to have returned.
686 /* NOINLINE: limit stack usage in caller */
687 static NOINLINE int send_d6_renew(uint32_t xid, struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
689 struct d6_packet packet;
692 /* Fill in: msg type, client id */
693 opt_ptr = init_d6_packet(&packet, DHCPREQUEST, xid);
696 opt_ptr = mempcpy(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
697 /* IA NA (contains requested IP) */
698 opt_ptr = mempcpy(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
701 * "param req" option according to -O, options specified with -x
703 opt_ptr = add_d6_client_options(opt_ptr);
705 bb_error_msg("sending %s", "renew");
707 return d6_send_kernel_packet(
708 &packet, (opt_ptr - (uint8_t*) &packet),
709 our_cur_ipv6, CLIENT_PORT6,
710 server_ipv6, SERVER_PORT6,
711 client_config.ifindex
713 return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
716 /* Unicast a DHCP release message */
717 static int send_d6_release(struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
719 struct d6_packet packet;
722 /* Fill in: msg type, client id */
723 opt_ptr = init_d6_packet(&packet, D6_MSG_RELEASE, random_xid());
725 opt_ptr = mempcpy(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
726 /* IA NA (contains our current IP) */
727 opt_ptr = mempcpy(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
729 bb_error_msg("sending %s", "release");
730 return d6_send_kernel_packet(
731 &packet, (opt_ptr - (uint8_t*) &packet),
732 our_cur_ipv6, CLIENT_PORT6,
733 server_ipv6, SERVER_PORT6,
734 client_config.ifindex
738 /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
739 /* NOINLINE: limit stack usage in caller */
740 static NOINLINE int d6_recv_raw_packet(struct in6_addr *peer_ipv6, struct d6_packet *d6_pkt, int fd)
743 struct ip6_udp_d6_packet packet;
745 bytes = safe_read(fd, &packet, sizeof(packet));
747 log1("packet read error, ignoring");
748 /* NB: possible down interface, etc. Caller should pause. */
749 return bytes; /* returns -1 */
752 if (bytes < (int) (sizeof(packet.ip6) + sizeof(packet.udp))) {
753 log1("packet is too short, ignoring");
757 if (bytes < sizeof(packet.ip6) + ntohs(packet.ip6.ip6_plen)) {
758 /* packet is bigger than sizeof(packet), we did partial read */
759 log1("oversized packet, ignoring");
763 /* ignore any extra garbage bytes */
764 bytes = sizeof(packet.ip6) + ntohs(packet.ip6.ip6_plen);
766 /* make sure its the right packet for us, and that it passes sanity checks */
767 if (packet.ip6.ip6_nxt != IPPROTO_UDP
768 || (packet.ip6.ip6_vfc >> 4) != 6
769 || packet.udp.dest != htons(CLIENT_PORT6)
770 /* || bytes > (int) sizeof(packet) - can't happen */
771 || packet.udp.len != packet.ip6.ip6_plen
773 log1("unrelated/bogus packet, ignoring");
777 //How to do this for ipv6?
778 // /* verify UDP checksum. IP header has to be modified for this */
779 // memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
780 // /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
781 // packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
782 // check = packet.udp.check;
783 // packet.udp.check = 0;
784 // if (check && check != inet_cksum((uint16_t *)&packet, bytes)) {
785 // log1("packet with bad UDP checksum received, ignoring");
790 *peer_ipv6 = packet.ip6.ip6_src; /* struct copy */
792 log1("received %s", "a packet");
793 d6_dump_packet(&packet.data);
795 bytes -= sizeof(packet.ip6) + sizeof(packet.udp);
796 memcpy(d6_pkt, &packet.data, bytes);
803 static int sockfd = -1;
805 #define LISTEN_NONE 0
806 #define LISTEN_KERNEL 1
808 static smallint listen_mode;
810 /* initial state: (re)start DHCP negotiation */
811 #define INIT_SELECTING 0
812 /* discover was sent, DHCPOFFER reply received */
814 /* select/renew was sent, DHCPACK reply received */
816 /* half of lease passed, want to renew it by sending unicast renew requests */
818 /* renew requests were not answered, lease is almost over, send broadcast renew */
820 /* manually requested renew (SIGUSR1) */
821 #define RENEW_REQUESTED 5
822 /* release, possibly manually requested (SIGUSR2) */
824 static smallint state;
826 static int d6_raw_socket(int ifindex)
829 struct sockaddr_ll sock;
834 * I've selected not to see LL header, so BPF doesn't see it, too.
835 * The filter may also pass non-IP and non-ARP packets, but we do
836 * a more complete check when receiving the message in userspace.
838 * and filter shamelessly stolen from:
840 * http://www.flamewarmaster.de/software/dhcpclient/
842 * There are a few other interesting ideas on that page (look under
843 * "Motivation"). Use of netlink events is most interesting. Think
844 * of various network servers listening for events and reconfiguring.
845 * That would obsolete sending HUP signals and/or make use of restarts.
847 * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
850 * TODO: make conditional?
853 static const struct sock_filter filter_instr[] = {
854 /* load 9th byte (protocol) */
855 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
856 /* jump to L1 if it is IPPROTO_UDP, else to L4 */
857 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
858 /* L1: load halfword from offset 6 (flags and frag offset) */
859 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
860 /* jump to L4 if any bits in frag offset field are set, else to L2 */
861 BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
862 /* L2: skip IP header (load index reg with header len) */
863 BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
864 /* load udp destination port from halfword[header_len + 2] */
865 BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
866 /* jump to L3 if udp dport is CLIENT_PORT6, else to L4 */
867 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
868 /* L3: accept packet */
869 BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
870 /* L4: discard packet */
871 BPF_STMT(BPF_RET|BPF_K, 0),
873 static const struct sock_fprog filter_prog = {
874 .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
875 /* casting const away: */
876 .filter = (struct sock_filter *) filter_instr,
880 log1("opening raw socket on ifindex %d", ifindex); //log2?
882 fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IPV6));
883 log1("got raw socket fd %d", fd); //log2?
885 sock.sll_family = AF_PACKET;
886 sock.sll_protocol = htons(ETH_P_IPV6);
887 sock.sll_ifindex = ifindex;
888 xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
891 if (CLIENT_PORT6 == 546) {
892 /* Use only if standard port is in use */
893 /* Ignoring error (kernel may lack support for this) */
894 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
895 sizeof(filter_prog)) >= 0)
896 log1("attached filter to raw socket fd %d", fd); // log?
900 log1("created raw socket");
905 static void change_listen_mode(int new_mode)
907 log1("entering listen mode: %s",
908 new_mode != LISTEN_NONE
909 ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
913 listen_mode = new_mode;
918 if (new_mode == LISTEN_KERNEL)
919 sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT6, client_config.interface);
920 else if (new_mode != LISTEN_NONE)
921 sockfd = d6_raw_socket(client_config.ifindex);
922 /* else LISTEN_NONE: sockfd stays closed */
925 /* Called only on SIGUSR1 */
926 static void perform_renew(void)
928 bb_error_msg("performing DHCP renew");
931 change_listen_mode(LISTEN_KERNEL);
934 state = RENEW_REQUESTED;
936 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
937 d6_run_script(NULL, "deconfig");
940 change_listen_mode(LISTEN_RAW);
941 state = INIT_SELECTING;
948 static void perform_d6_release(struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
950 /* send release packet */
953 || state == REBINDING
954 || state == RENEW_REQUESTED
956 bb_error_msg("unicasting a release");
957 send_d6_release(server_ipv6, our_cur_ipv6); /* unicast */
959 bb_error_msg("entering released state");
961 * We can be here on: SIGUSR2,
962 * or on exit (SIGTERM) and -R "release on quit" is specified.
963 * Users requested to be notified in all cases, even if not in one
964 * of the states above.
966 d6_run_script(NULL, "deconfig");
967 change_listen_mode(LISTEN_NONE);
971 ///static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
973 /// uint8_t *storage;
974 /// int len = strnlen(str, 255);
975 /// storage = xzalloc(len + extra + OPT_DATA);
976 /// storage[OPT_CODE] = code;
977 /// storage[OPT_LEN] = len + extra;
978 /// memcpy(storage + extra + OPT_DATA, str, len);
983 static void client_background(void)
986 logmode &= ~LOGMODE_STDIO;
987 /* rewrite pidfile, as our pid is different now */
988 write_pidfile(client_config.pidfile);
992 //usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
993 //usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
995 //usage:# define IF_UDHCP_VERBOSE(...)
997 //usage:#define udhcpc6_trivial_usage
998 //usage: "[-fbnq"IF_UDHCP_VERBOSE("v")"oR] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]\n"
999 //usage: " [-x OPT:VAL]... [-O OPT]..." IF_FEATURE_UDHCP_PORT(" [-P N]")
1000 //usage:#define udhcpc6_full_usage "\n"
1001 //usage: IF_LONG_OPTS(
1002 //usage: "\n -i,--interface IFACE Interface to use (default eth0)"
1003 //usage: "\n -p,--pidfile FILE Create pidfile"
1004 //usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
1005 //usage: "\n -B,--broadcast Request broadcast replies"
1006 //usage: "\n -t,--retries N Send up to N discover packets"
1007 //usage: "\n -T,--timeout N Pause between packets (default 3 seconds)"
1008 //usage: "\n -A,--tryagain N Wait N seconds after failure (default 20)"
1009 //usage: "\n -f,--foreground Run in foreground"
1010 //usage: USE_FOR_MMU(
1011 //usage: "\n -b,--background Background if lease is not obtained"
1013 //usage: "\n -n,--now Exit if lease is not obtained"
1014 //usage: "\n -q,--quit Exit after obtaining lease"
1015 //usage: "\n -R,--release Release IP on exit"
1016 //usage: "\n -S,--syslog Log to syslog too"
1017 //usage: IF_FEATURE_UDHCP_PORT(
1018 //usage: "\n -P,--client-port N Use port N (default 546)"
1020 ////usage: IF_FEATURE_UDHCPC_ARPING(
1021 ////usage: "\n -a,--arping Use arping to validate offered address"
1023 //usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
1024 //usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
1025 //usage: "\n -r,--request IP Request this IP address"
1026 //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
1027 //usage: "\n Examples of string, numeric, and hex byte opts:"
1028 //usage: "\n -x hostname:bbox - option 12"
1029 //usage: "\n -x lease:3600 - option 51 (lease time)"
1030 //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
1031 //usage: IF_UDHCP_VERBOSE(
1032 //usage: "\n -v Verbose"
1035 //usage: IF_NOT_LONG_OPTS(
1036 //usage: "\n -i IFACE Interface to use (default eth0)"
1037 //usage: "\n -p FILE Create pidfile"
1038 //usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
1039 //usage: "\n -B Request broadcast replies"
1040 //usage: "\n -t N Send up to N discover packets"
1041 //usage: "\n -T N Pause between packets (default 3 seconds)"
1042 //usage: "\n -A N Wait N seconds (default 20) after failure"
1043 //usage: "\n -f Run in foreground"
1044 //usage: USE_FOR_MMU(
1045 //usage: "\n -b Background if lease is not obtained"
1047 //usage: "\n -n Exit if lease is not obtained"
1048 //usage: "\n -q Exit after obtaining lease"
1049 //usage: "\n -R Release IP on exit"
1050 //usage: "\n -S Log to syslog too"
1051 //usage: IF_FEATURE_UDHCP_PORT(
1052 //usage: "\n -P N Use port N (default 546)"
1054 ////usage: IF_FEATURE_UDHCPC_ARPING(
1055 ////usage: "\n -a Use arping to validate offered address"
1057 //usage: "\n -O OPT Request option OPT from server (cumulative)"
1058 //usage: "\n -o Don't request any options (unless -O is given)"
1059 //usage: "\n -r IP Request this IP address"
1060 //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
1061 //usage: "\n Examples of string, numeric, and hex byte opts:"
1062 //usage: "\n -x hostname:bbox - option 12"
1063 //usage: "\n -x lease:3600 - option 51 (lease time)"
1064 //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
1065 //usage: IF_UDHCP_VERBOSE(
1066 //usage: "\n -v Verbose"
1069 //usage: "\nSignals:"
1070 //usage: "\n USR1 Renew lease"
1071 //usage: "\n USR2 Release lease"
1074 int udhcpc6_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1075 int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
1078 IF_FEATURE_UDHCP_PORT(char *str_P;)
1079 void *clientid_mac_ptr;
1080 llist_t *list_O = NULL;
1081 llist_t *list_x = NULL;
1082 int tryagain_timeout = 20;
1083 int discover_timeout = 3;
1084 int discover_retries = 3;
1085 struct in6_addr srv6_buf;
1086 struct in6_addr ipv6_buf;
1087 struct in6_addr *requested_ipv6;
1090 int timeout; /* must be signed */
1091 unsigned already_waited_sec;
1095 setup_common_bufsiz();
1097 /* Default options */
1098 IF_FEATURE_UDHCP_PORT(SERVER_PORT6 = 547;)
1099 IF_FEATURE_UDHCP_PORT(CLIENT_PORT6 = 546;)
1100 client_config.interface = "eth0";
1101 client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
1103 /* Parse command line */
1104 /* O,x: list; -T,-t,-A take numeric param */
1105 IF_UDHCP_VERBOSE(opt_complementary = "vv";)
1106 IF_LONG_OPTS(applet_long_options = udhcpc6_longopts;)
1107 opt = getopt32(argv, "i:np:qRr:s:T:+t:+SA:+O:*ox:*f"
1109 ///IF_FEATURE_UDHCPC_ARPING("a")
1110 IF_FEATURE_UDHCP_PORT("P:")
1112 , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
1113 , &client_config.script /* s */
1114 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
1117 IF_FEATURE_UDHCP_PORT(, &str_P)
1118 IF_UDHCP_VERBOSE(, &dhcp_verbose)
1120 requested_ipv6 = NULL;
1122 if (inet_pton(AF_INET6, str_r, &ipv6_buf) <= 0)
1123 bb_error_msg_and_die("bad IPv6 address '%s'", str_r);
1124 requested_ipv6 = &ipv6_buf;
1126 #if ENABLE_FEATURE_UDHCP_PORT
1128 CLIENT_PORT6 = xatou16(str_P);
1129 SERVER_PORT6 = CLIENT_PORT6 + 1;
1133 char *optstr = llist_pop(&list_O);
1134 unsigned n = bb_strtou(optstr, NULL, 0);
1135 if (errno || n > 254) {
1136 n = udhcp_option_idx(optstr, d6_option_strings);
1137 n = d6_optflags[n].code;
1139 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
1141 if (!(opt & OPT_o)) {
1143 for (i = 0; (n = d6_optflags[i].code) != 0; i++) {
1144 if (d6_optflags[i].flags & OPTION_REQ) {
1145 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
1150 char *optstr = llist_pop(&list_x);
1151 char *colon = strchr(optstr, ':');
1154 /* now it looks similar to udhcpd's config file line:
1155 * "optname optval", using the common routine: */
1156 udhcp_str2optset(optstr, &client_config.options, d6_optflags, d6_option_strings);
1158 *colon = ':'; /* restore it for NOMMU reexec */
1161 if (d6_read_interface(client_config.interface,
1162 &client_config.ifindex,
1163 &client6_data.ll_ip6,
1164 client_config.client_mac)
1169 /* Create client ID based on mac, set clientid_mac_ptr */
1171 struct d6_option *clientid;
1172 clientid = xzalloc(2+2+2+2+6);
1173 clientid->code = D6_OPT_CLIENTID;
1174 clientid->len = 2+2+6;
1175 clientid->data[1] = 3; /* DUID-LL */
1176 clientid->data[3] = 1; /* ethernet */
1177 clientid_mac_ptr = clientid->data + 2+2;
1178 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1179 client_config.clientid = (void*)clientid;
1183 /* on NOMMU reexec (i.e., background) early */
1184 if (!(opt & OPT_f)) {
1185 bb_daemonize_or_rexec(0 /* flags */, argv);
1186 logmode = LOGMODE_NONE;
1190 openlog(applet_name, LOG_PID, LOG_DAEMON);
1191 logmode |= LOGMODE_SYSLOG;
1194 /* Make sure fd 0,1,2 are open */
1195 bb_sanitize_stdio();
1196 /* Equivalent of doing a fflush after every \n */
1198 /* Create pidfile */
1199 write_pidfile(client_config.pidfile);
1200 /* Goes to stdout (unless NOMMU) and possibly syslog */
1201 bb_error_msg("started, v"BB_VER);
1202 /* Set up the signal pipe */
1204 /* We want random_xid to be random... */
1205 srand(monotonic_us());
1207 state = INIT_SELECTING;
1208 d6_run_script(NULL, "deconfig");
1209 change_listen_mode(LISTEN_RAW);
1212 already_waited_sec = 0;
1214 /* Main event loop. select() waits on signal pipe and possibly
1216 * "continue" statements in code below jump to the top of the loop.
1220 struct pollfd pfds[2];
1221 struct d6_packet packet;
1222 uint8_t *packet_end;
1223 /* silence "uninitialized!" warning */
1224 unsigned timestamp_before_wait = timestamp_before_wait;
1226 //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
1228 /* Was opening raw or udp socket here
1229 * if (listen_mode != LISTEN_NONE && sockfd < 0),
1230 * but on fast network renew responses return faster
1231 * than we open sockets. Thus this code is moved
1232 * to change_listen_mode(). Thus we open listen socket
1233 * BEFORE we send renew request (see "case BOUND:"). */
1235 udhcp_sp_fd_set(pfds, sockfd);
1237 tv = timeout - already_waited_sec;
1239 /* If we already timed out, fall through with retval = 0, else... */
1241 log1("waiting on select %u seconds", tv);
1242 timestamp_before_wait = (unsigned)monotonic_sec();
1243 retval = poll(pfds, 2, tv < INT_MAX/1000 ? tv * 1000 : INT_MAX);
1245 /* EINTR? A signal was caught, don't panic */
1246 if (errno == EINTR) {
1247 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1250 /* Else: an error occured, panic! */
1251 bb_perror_msg_and_die("select");
1255 /* If timeout dropped to zero, time to become active:
1256 * resend discover/renew/whatever
1259 /* When running on a bridge, the ifindex may have changed
1260 * (e.g. if member interfaces were added/removed
1261 * or if the status of the bridge changed).
1262 * Refresh ifindex and client_mac:
1264 if (d6_read_interface(client_config.interface,
1265 &client_config.ifindex,
1266 &client6_data.ll_ip6,
1267 client_config.client_mac)
1269 goto ret0; /* iface is gone? */
1272 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1274 /* We will restart the wait in any case */
1275 already_waited_sec = 0;
1278 case INIT_SELECTING:
1279 if (!discover_retries || packet_num < discover_retries) {
1280 if (packet_num == 0)
1283 send_d6_discover(xid, requested_ipv6);
1284 timeout = discover_timeout;
1289 d6_run_script(NULL, "leasefail");
1290 #if BB_MMU /* -b is not supported on NOMMU */
1291 if (opt & OPT_b) { /* background if no lease */
1292 bb_error_msg("no lease, forking to background");
1293 client_background();
1294 /* do not background again! */
1295 opt = ((opt & ~OPT_b) | OPT_f);
1298 if (opt & OPT_n) { /* abort if no lease */
1299 bb_error_msg("no lease, failing");
1303 /* wait before trying again */
1304 timeout = tryagain_timeout;
1308 if (!discover_retries || packet_num < discover_retries) {
1309 /* send multicast select packet */
1310 send_d6_select(xid);
1311 timeout = discover_timeout;
1315 /* Timed out, go back to init state.
1316 * "discover...select...discover..." loops
1317 * were seen in the wild. Treat them similarly
1318 * to "no response to discover" case */
1319 change_listen_mode(LISTEN_RAW);
1320 state = INIT_SELECTING;
1323 /* 1/2 lease passed, enter renewing state */
1325 client_config.first_secs = 0; /* make secs field count from 0 */
1326 change_listen_mode(LISTEN_KERNEL);
1327 log1("entering renew state");
1328 /* fall right through */
1329 case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
1330 case_RENEW_REQUESTED:
1333 /* send an unicast renew request */
1334 /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1335 * a new UDP socket for sending inside send_renew.
1336 * I hazard to guess existing listening socket
1337 * is somehow conflicting with it, but why is it
1338 * not deterministic then?! Strange.
1339 * Anyway, it does recover by eventually failing through
1340 * into INIT_SELECTING state.
1342 send_d6_renew(xid, &srv6_buf, requested_ipv6);
1346 /* Timed out, enter rebinding state */
1347 log1("entering rebinding state");
1349 /* fall right through */
1351 /* Switch to bcast receive */
1352 change_listen_mode(LISTEN_RAW);
1353 /* Lease is *really* about to run out,
1354 * try to find DHCP server using broadcast */
1356 /* send a broadcast renew request */
1357 send_d6_renew(xid, /*server_ipv6:*/ NULL, requested_ipv6);
1361 /* Timed out, enter init state */
1362 bb_error_msg("lease lost, entering init state");
1363 d6_run_script(NULL, "deconfig");
1364 state = INIT_SELECTING;
1365 client_config.first_secs = 0; /* make secs field count from 0 */
1366 /*timeout = 0; - already is */
1369 /* case RELEASED: */
1371 /* yah, I know, *you* say it would never happen */
1373 continue; /* back to main loop */
1374 } /* if select timed out */
1376 /* select() didn't timeout, something happened */
1378 /* Is it a signal? */
1379 /* note: udhcp_sp_read checks poll result before reading */
1380 switch (udhcp_sp_read(pfds)) {
1382 client_config.first_secs = 0; /* make secs field count from 0 */
1383 already_waited_sec = 0;
1385 if (state == RENEW_REQUESTED) {
1386 /* We might be either on the same network
1387 * (in which case renew might work),
1388 * or we might be on a completely different one
1389 * (in which case renew won't ever succeed).
1390 * For the second case, must make sure timeout
1391 * is not too big, or else we can send
1392 * futile renew requests for hours.
1393 * (Ab)use -A TIMEOUT value (usually 20 sec)
1394 * as a cap on the timeout.
1396 if (timeout > tryagain_timeout)
1397 timeout = tryagain_timeout;
1398 goto case_RENEW_REQUESTED;
1400 /* Start things over */
1402 /* Kill any timeouts, user wants this to hurry along */
1406 perform_d6_release(&srv6_buf, requested_ipv6);
1410 bb_error_msg("received %s", "SIGTERM");
1414 /* Is it a packet? */
1415 if (listen_mode == LISTEN_NONE || !pfds[1].revents)
1421 /* A packet is ready, read it */
1422 if (listen_mode == LISTEN_KERNEL)
1423 len = d6_recv_kernel_packet(&srv6_buf, &packet, sockfd);
1425 len = d6_recv_raw_packet(&srv6_buf, &packet, sockfd);
1427 /* Error is severe, reopen socket */
1428 bb_error_msg("read error: %s, reopening socket", strerror(errno));
1429 sleep(discover_timeout); /* 3 seconds by default */
1430 change_listen_mode(listen_mode); /* just close and reopen */
1432 /* If this packet will turn out to be unrelated/bogus,
1433 * we will go back and wait for next one.
1434 * Be sure timeout is properly decreased. */
1435 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1438 packet_end = (uint8_t*)&packet + len;
1441 if ((packet.d6_xid32 & htonl(0x00ffffff)) != xid) {
1442 log1("xid %x (our is %x), ignoring packet",
1443 (unsigned)(packet.d6_xid32 & htonl(0x00ffffff)), (unsigned)xid);
1448 case INIT_SELECTING:
1449 if (packet.d6_msg_type == D6_MSG_ADVERTISE)
1451 /* DHCPv6 has "Rapid Commit", when instead of Advertise,
1452 * server sends Reply right away.
1453 * Fall through to check for this case.
1457 case RENEW_REQUESTED:
1459 if (packet.d6_msg_type == D6_MSG_REPLY) {
1460 uint32_t lease_seconds;
1461 struct d6_option *option, *iaaddr;
1463 option = d6_find_option(packet.d6_options, packet_end, D6_OPT_STATUS_CODE);
1464 if (option && (option->data[0] | option->data[1]) != 0) {
1465 /* return to init state */
1466 bb_error_msg("received DHCP NAK (%u)", option->data[4]);
1467 d6_run_script(&packet, "nak");
1468 if (state != REQUESTING)
1469 d6_run_script(NULL, "deconfig");
1470 change_listen_mode(LISTEN_RAW);
1471 sleep(3); /* avoid excessive network traffic */
1472 state = INIT_SELECTING;
1473 client_config.first_secs = 0; /* make secs field count from 0 */
1474 requested_ipv6 = NULL;
1477 already_waited_sec = 0;
1480 option = d6_copy_option(packet.d6_options, packet_end, D6_OPT_SERVERID);
1482 bb_error_msg("no server ID, ignoring packet");
1484 /* still selecting - this server looks bad */
1486 //Note: we do not bother comparing server IDs in Advertise and Reply msgs.
1487 //server_id variable is used solely for creation of proper server_id option
1488 //in outgoing packets. (why DHCPv6 even introduced it is a mystery).
1489 free(client6_data.server_id);
1490 client6_data.server_id = option;
1491 if (packet.d6_msg_type == D6_MSG_ADVERTISE) {
1492 /* enter requesting state */
1496 already_waited_sec = 0;
1499 /* It's a D6_MSG_REPLY */
1501 * RFC 3315 18.1.8. Receipt of Reply Messages
1503 * Upon the receipt of a valid Reply message in response to a Solicit
1504 * (with a Rapid Commit option), Request, Confirm, Renew, Rebind or
1505 * Information-request message, the client extracts the configuration
1506 * information contained in the Reply. The client MAY choose to report
1507 * any status code or message from the status code option in the Reply
1510 * The client SHOULD perform duplicate address detection [17] on each of
1511 * the addresses in any IAs it receives in the Reply message before
1512 * using that address for traffic. If any of the addresses are found to
1513 * be in use on the link, the client sends a Decline message to the
1514 * server as described in section 18.1.7.
1516 * If the Reply was received in response to a Solicit (with a Rapid
1517 * Commit option), Request, Renew or Rebind message, the client updates
1518 * the information it has recorded about IAs from the IA options
1519 * contained in the Reply message:
1521 * - Record T1 and T2 times.
1523 * - Add any new addresses in the IA option to the IA as recorded by
1526 * - Update lifetimes for any addresses in the IA option that the
1527 * client already has recorded in the IA.
1529 * - Discard any addresses from the IA, as recorded by the client, that
1530 * have a valid lifetime of 0 in the IA Address option.
1532 * - Leave unchanged any information about addresses the client has
1533 * recorded in the IA but that were not included in the IA from the
1536 * Management of the specific configuration information is detailed in
1537 * the definition of each option in section 22.
1539 * If the client receives a Reply message with a Status Code containing
1540 * UnspecFail, the server is indicating that it was unable to process
1541 * the message due to an unspecified failure condition. If the client
1542 * retransmits the original message to the same server to retry the
1543 * desired operation, the client MUST limit the rate at which it
1544 * retransmits the message and limit the duration of the time during
1545 * which it retransmits the message.
1547 * When the client receives a Reply message with a Status Code option
1548 * with the value UseMulticast, the client records the receipt of the
1549 * message and sends subsequent messages to the server through the
1550 * interface on which the message was received using multicast. The
1551 * client resends the original message using multicast.
1553 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1554 * | OPTION_IA_NA | option-len |
1555 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1556 * | IAID (4 octets) |
1557 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1559 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1561 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1565 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1568 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1569 * | OPTION_IAADDR | option-len |
1570 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1575 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1576 * | preferred-lifetime |
1577 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1578 * | valid-lifetime |
1579 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1581 * . IAaddr-options .
1583 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1585 free(client6_data.ia_na);
1586 client6_data.ia_na = d6_copy_option(packet.d6_options, packet_end, D6_OPT_IA_NA);
1587 if (!client6_data.ia_na) {
1588 bb_error_msg("no %s option, ignoring packet", "IA_NA");
1591 if (client6_data.ia_na->len < (4 + 4 + 4) + (2 + 2 + 16 + 4 + 4)) {
1592 bb_error_msg("IA_NA option is too short:%d bytes", client6_data.ia_na->len);
1595 iaaddr = d6_find_option(client6_data.ia_na->data + 4 + 4 + 4,
1596 client6_data.ia_na->data + client6_data.ia_na->len,
1600 bb_error_msg("no %s option, ignoring packet", "IAADDR");
1603 if (iaaddr->len < (16 + 4 + 4)) {
1604 bb_error_msg("IAADDR option is too short:%d bytes", iaaddr->len);
1607 /* Note: the address is sufficiently aligned for cast:
1608 * we _copied_ IA-NA, and copy is always well-aligned.
1610 requested_ipv6 = (struct in6_addr*) iaaddr->data;
1611 move_from_unaligned32(lease_seconds, iaaddr->data + 16 + 4);
1612 lease_seconds = ntohl(lease_seconds);
1613 /* paranoia: must not be too small and not prone to overflows */
1614 if (lease_seconds < 0x10)
1615 lease_seconds = 0x10;
1616 /// TODO: check for 0 lease time?
1617 if (lease_seconds > 0x7fffffff / 1000)
1618 lease_seconds = 0x7fffffff / 1000;
1619 /* enter bound state */
1620 timeout = lease_seconds / 2;
1621 bb_error_msg("lease obtained, lease time %u",
1622 /*inet_ntoa(temp_addr),*/ (unsigned)lease_seconds);
1623 d6_run_script(&packet, state == REQUESTING ? "bound" : "renew");
1626 change_listen_mode(LISTEN_NONE);
1627 if (opt & OPT_q) { /* quit after lease */
1630 /* future renew failures should not exit (JM) */
1632 #if BB_MMU /* NOMMU case backgrounded earlier */
1633 if (!(opt & OPT_f)) {
1634 client_background();
1635 /* do not background again! */
1636 opt = ((opt & ~OPT_b) | OPT_f);
1639 already_waited_sec = 0;
1640 continue; /* back to main loop */
1643 /* case BOUND: - ignore all packets */
1644 /* case RELEASED: - ignore all packets */
1646 /* back to main loop */
1647 } /* for (;;) - main loop ends */
1650 if (opt & OPT_R) /* release on quit */
1651 perform_d6_release(&srv6_buf, requested_ipv6);
1654 /*if (client_config.pidfile) - remove_pidfile has its own check */
1655 remove_pidfile(client_config.pidfile);