1 /* vi: set sw=4 ts=4: */
5 * Russ Dill <Russ.Dill@asu.edu> July 2001
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 /* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
23 #define WANT_PIDFILE 1
28 #include <asm/types.h>
29 /*#if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined(_NEWLIB_VERSION)
30 # include <linux/if_packet.h>
31 # include <netinet/if_ether.h>
33 # include <linux/if_packet.h>
34 # include <linux/if_ether.h>
36 #include <linux/filter.h>
38 /* "struct client_config_t client_config" is in bb_common_bufsiz1 */
41 static const char udhcpc_longopts
[] ALIGN1
=
42 "clientid-none\0" No_argument
"C"
43 "vendorclass\0" Required_argument
"V"
44 "hostname\0" Required_argument
"H"
45 "fqdn\0" Required_argument
"F"
46 "interface\0" Required_argument
"i"
47 "now\0" No_argument
"n"
48 "pidfile\0" Required_argument
"p"
49 "quit\0" No_argument
"q"
50 "release\0" No_argument
"R"
51 "request\0" Required_argument
"r"
52 "script\0" Required_argument
"s"
53 "timeout\0" Required_argument
"T"
54 "version\0" No_argument
"v"
55 "retries\0" Required_argument
"t"
56 "tryagain\0" Required_argument
"A"
57 "syslog\0" No_argument
"S"
58 "request-option\0" Required_argument
"O"
59 "no-default-options\0" No_argument
"o"
60 "foreground\0" No_argument
"f"
61 "background\0" No_argument
"b"
62 "broadcast\0" No_argument
"B"
63 IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument
"a")
64 IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument
"P")
67 /* Must match getopt32 option string order */
90 OPT_m
= 1 << 21, // zzz
91 /* The rest has variable bit positions, need to be clever */
93 USE_FOR_MMU( OPTBIT_b
,)
94 IF_FEATURE_UDHCPC_ARPING(OPTBIT_a
,)
95 IF_FEATURE_UDHCP_PORT( OPTBIT_P
,)
96 USE_FOR_MMU( OPT_b
= 1 << OPTBIT_b
,)
97 IF_FEATURE_UDHCPC_ARPING(OPT_a
= 1 << OPTBIT_a
,)
98 IF_FEATURE_UDHCP_PORT( OPT_P
= 1 << OPTBIT_P
,)
102 /*** Script execution code ***/
104 /* get a rough idea of how long an option will be (rounding up...) */
105 static const uint8_t len_of_option_as_string
[] = {
106 [OPTION_IP
] = sizeof("255.255.255.255 "),
107 [OPTION_IP_PAIR
] = sizeof("255.255.255.255 ") * 2,
108 [OPTION_STATIC_ROUTES
] = sizeof("255.255.255.255/32 255.255.255.255 "),
109 [OPTION_6RD
] = sizeof("32 128 FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 255.255.255.255 "),
110 [OPTION_STRING
] = 1,
111 [OPTION_STRING_HOST
] = 1,
112 #if ENABLE_FEATURE_UDHCP_RFC3397
113 [OPTION_DNS_STRING
] = 1, /* unused */
114 /* Hmmm, this severely overestimates size if SIP_SERVERS option
115 * is in domain name form: N-byte option in binary form
116 * mallocs ~16*N bytes. But it is freed almost at once.
118 [OPTION_SIP_SERVERS
] = sizeof("255.255.255.255 "),
120 // [OPTION_BOOLEAN ] = sizeof("yes "),
121 [OPTION_U8
] = sizeof("255 "),
122 [OPTION_U16
] = sizeof("65535 "),
123 // [OPTION_S16 ] = sizeof("-32768 "),
124 [OPTION_U32
] = sizeof("4294967295 "),
125 [OPTION_S32
] = sizeof("-2147483684 "),
128 /* note: ip is a pointer to an IP in network order, possibly misaliged */
129 static int sprint_nip(char *dest
, const char *pre
, const uint8_t *ip
)
131 return sprintf(dest
, "%s%u.%u.%u.%u", pre
, ip
[0], ip
[1], ip
[2], ip
[3]);
134 /* really simple implementation, just count the bits */
135 static int mton(uint32_t mask
)
138 mask
= ntohl(mask
); /* 111110000-like bit pattern */
146 /* Check if a given label represents a valid DNS label
147 * Return pointer to the first character after the label upon success,
151 /* We don't need to be particularly anal. For example, allowing _, hyphen
152 * at the end, or leading and trailing dots would be ok, since it
153 * can't be used for attacks. (Leading hyphen can be, if someone uses
155 * in the script: then hostname may be treated as an option)
157 static const char *valid_domain_label(const char *label
)
164 if ((ch
|0x20) < 'a' || (ch
|0x20) > 'z') {
166 /* label must begin with letter */
169 if (ch
< '0' || ch
> '9') {
170 if (ch
== '\0' || ch
== '.')
172 /* DNS allows only '-', but we are more permissive */
173 if (ch
!= '-' && ch
!= '_')
180 //if (pos > 63) /* NS_MAXLABEL; labels must be 63 chars or less */
185 /* Check if a given name represents a valid DNS name */
186 /* See RFC1035, 2.3.1 */
187 static int good_hostname(const char *name
)
189 //const char *start = name;
192 name
= valid_domain_label(name
);
198 //return ((name - start) < 1025); /* NS_MAXDNAME */
203 /* Create "opt_name=opt_value" string */
204 static NOINLINE
char *xmalloc_optname_optval(uint8_t *option
, const struct dhcp_optflag
*optflag
, const char *opt_name
)
206 unsigned upper_length
;
207 int len
, type
, optlen
;
210 /* option points to OPT_DATA, need to go back to get OPT_LEN */
211 len
= option
[-OPT_DATA
+ OPT_LEN
];
213 type
= optflag
->flags
& OPTION_TYPE_MASK
;
214 optlen
= dhcp_option_lengths
[type
];
215 upper_length
= len_of_option_as_string
[type
]
216 * ((unsigned)(len
+ optlen
- 1) / (unsigned)optlen
);
218 dest
= ret
= xmalloc(upper_length
+ strlen(opt_name
) + 2);
219 dest
+= sprintf(ret
, "%s=", opt_name
);
221 while (len
>= optlen
) {
225 dest
+= sprint_nip(dest
, "", option
);
226 if (type
== OPTION_IP
)
228 dest
+= sprint_nip(dest
, "/", option
+ 4);
230 // case OPTION_BOOLEAN:
231 // dest += sprintf(dest, *option ? "yes" : "no");
234 dest
+= sprintf(dest
, "%u", *option
);
239 move_from_unaligned16(val_u16
, option
);
240 dest
+= sprintf(dest
, "%u", ntohs(val_u16
));
246 move_from_unaligned32(val_u32
, option
);
247 dest
+= sprintf(dest
, type
== OPTION_U32
? "%lu" : "%ld", (unsigned long) ntohl(val_u32
));
250 /* Note: options which use 'return' instead of 'break'
251 * (for example, OPTION_STRING) skip the code which handles
252 * the case of list of options.
255 case OPTION_STRING_HOST
:
256 memcpy(dest
, option
, len
);
258 if (type
== OPTION_STRING_HOST
&& !good_hostname(dest
))
259 safe_strncpy(dest
, "bad", len
);
261 case OPTION_STATIC_ROUTES
: {
262 /* Option binary format:
263 * mask [one byte, 0..32]
264 * ip [big endian, 0..4 bytes depending on mask]
265 * router [big endian, 4 bytes]
268 * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
270 const char *pfx
= "";
272 while (len
>= 1 + 4) { /* mask + 0-byte ip + router */
285 bytes
= (mask
+ 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
286 while (--bytes
>= 0) {
294 dest
+= sprint_nip(dest
, pfx
, (void*) &nip
);
296 dest
+= sprintf(dest
, "/%u ", mask
);
298 dest
+= sprint_nip(dest
, "", option
);
306 /* Option binary format (see RFC 5969):
308 * 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
309 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
310 * | OPTION_6RD | option-length | IPv4MaskLen | 6rdPrefixLen |
311 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
313 * ... (16 octets) ...
314 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
315 * ... 6rdBRIPv4Address(es) ...
316 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
317 * We convert it to a string
318 * "IPv4MaskLen 6rdPrefixLen 6rdPrefix 6rdBRIPv4Address..."
320 * Sanity check: ensure that our length is at least 22 bytes, that
322 * 6rdPrefixLen <= 128,
323 * 6rdPrefixLen + (32 - IPv4MaskLen) <= 128
324 * (2nd condition need no check - it follows from 1st and 3rd).
325 * Else, return envvar with empty value ("optname=")
327 if (len
>= (1 + 1 + 16 + 4)
329 && (option
[1] + 32 - option
[0]) <= 128
332 dest
+= sprintf(dest
, "%u ", *option
++);
334 dest
+= sprintf(dest
, "%u ", *option
++);
336 dest
+= sprint_nip6(dest
, /* "", */ option
);
338 len
-= 1 + 1 + 16 + 4;
339 /* "+ 4" above corresponds to the length of IPv4 addr
340 * we consume in the loop below */
342 /* 6rdBRIPv4Address(es) */
343 dest
+= sprint_nip(dest
, " ", option
);
345 len
-= 4; /* do we have yet another 4+ bytes? */
352 #if ENABLE_FEATURE_UDHCP_RFC3397
353 case OPTION_DNS_STRING
:
354 /* unpack option into dest; use ret for prefix (i.e., "optname=") */
355 dest
= dname_dec(option
, len
, ret
);
360 /* error. return "optname=" string */
362 case OPTION_SIP_SERVERS
:
363 /* Option binary format:
365 * type=0: domain names, dns-compressed
370 if (option
[-1] == 0) {
371 dest
= dname_dec(option
, len
, ret
);
377 if (option
[-1] == 1) {
378 const char *pfx
= "";
383 dest
+= sprint_nip(dest
, pfx
, option
);
392 /* If we are here, try to format any remaining data
393 * in the option as another, similarly-formatted option
397 // TODO: it can be a list only if (optflag->flags & OPTION_LIST).
398 // Should we bail out/warn if we see multi-ip option which is
399 // not allowed to be such (for example, DHCP_BROADCAST)? -
400 if (len
< optlen
/* || !(optflag->flags & OPTION_LIST) */)
409 /* put all the parameters into the environment */
410 static char **fill_envp(struct dhcp_packet
*packet
)
415 const char *opt_name
;
417 uint8_t overload
= 0;
419 #define BITMAP unsigned
420 #define BBITS (sizeof(BITMAP) * 8)
421 #define BMASK(i) (1 << (i & (sizeof(BITMAP) * 8 - 1)))
422 #define FOUND_OPTS(i) (found_opts[(unsigned)i / BBITS])
423 BITMAP found_opts
[256 / BBITS
];
425 memset(found_opts
, 0, sizeof(found_opts
));
427 /* We need 6 elements for:
429 * "ip=N.N.N.N" from packet->yiaddr
430 * "siaddr=IP" from packet->siaddr_nip (unless 0)
431 * "boot_file=FILE" from packet->file (unless overloaded)
432 * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded)
436 /* +1 element for each option, +2 for subnet option: */
438 /* note: do not search for "pad" (0) and "end" (255) options */
439 //TODO: change logic to scan packet _once_
440 for (i
= 1; i
< 255; i
++) {
441 temp
= udhcp_get_option(packet
, i
);
443 if (i
== DHCP_OPTION_OVERLOAD
)
445 else if (i
== DHCP_SUBNET
)
446 envc
++; /* for $mask */
448 /*if (i != DHCP_MESSAGE_TYPE)*/
449 FOUND_OPTS(i
) |= BMASK(i
);
453 curr
= envp
= xzalloc(sizeof(envp
[0]) * envc
);
455 *curr
= xasprintf("interface=%s", client_config
.interface
);
461 /* Export BOOTP fields. Fields we don't (yet?) export:
462 * uint8_t op; // always BOOTREPLY
463 * uint8_t htype; // hardware address type. 1 = 10mb ethernet
464 * uint8_t hlen; // hardware address length
465 * uint8_t hops; // used by relay agents only
467 * uint16_t secs; // elapsed since client began acquisition/renewal
468 * uint16_t flags; // only one flag so far: bcast. Never set by server
469 * uint32_t ciaddr; // client IP (usually == yiaddr. can it be different
470 * // if during renew server wants to give us differn IP?)
471 * uint32_t gateway_nip; // relay agent IP address
472 * uint8_t chaddr[16]; // link-layer client hardware address (MAC)
473 * TODO: export gateway_nip as $giaddr?
475 /* Most important one: yiaddr as $ip */
476 *curr
= xmalloc(sizeof("ip=255.255.255.255"));
477 sprint_nip(*curr
, "ip=", (uint8_t *) &packet
->yiaddr
);
479 if (packet
->siaddr_nip
) {
480 /* IP address of next server to use in bootstrap */
481 *curr
= xmalloc(sizeof("siaddr=255.255.255.255"));
482 sprint_nip(*curr
, "siaddr=", (uint8_t *) &packet
->siaddr_nip
);
485 if (!(overload
& FILE_FIELD
) && packet
->file
[0]) {
486 /* watch out for invalid packets */
487 *curr
= xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR
"s", packet
->file
);
490 if (!(overload
& SNAME_FIELD
) && packet
->sname
[0]) {
491 /* watch out for invalid packets */
492 *curr
= xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR
"s", packet
->sname
);
496 /* Export known DHCP options */
497 opt_name
= dhcp_option_strings
;
500 uint8_t code
= dhcp_optflags
[i
].code
;
501 BITMAP
*found_ptr
= &FOUND_OPTS(code
);
502 BITMAP found_mask
= BMASK(code
);
503 if (!(*found_ptr
& found_mask
))
505 *found_ptr
&= ~found_mask
; /* leave only unknown options */
506 temp
= udhcp_get_option(packet
, code
);
507 *curr
= xmalloc_optname_optval(temp
, &dhcp_optflags
[i
], opt_name
);
509 if (code
== DHCP_SUBNET
) {
510 /* Subnet option: make things like "$ip/$mask" possible */
512 move_from_unaligned32(subnet
, temp
);
513 *curr
= xasprintf("mask=%u", mton(subnet
));
517 opt_name
+= strlen(opt_name
) + 1;
520 /* Export unknown options */
521 for (i
= 0; i
< 256;) {
522 BITMAP bitmap
= FOUND_OPTS(i
);
527 if (bitmap
& BMASK(i
)) {
530 temp
= udhcp_get_option(packet
, i
);
531 /* udhcp_get_option returns ptr to data portion,
532 * need to go back to get len
534 len
= temp
[-OPT_DATA
+ OPT_LEN
];
535 *curr
= xmalloc(sizeof("optNNN=") + 1 + len
*2);
536 ofs
= sprintf(*curr
, "opt%u=", i
);
537 *bin2hex(*curr
+ ofs
, (void*) temp
, len
) = '\0';
546 /* Call a script with a par file and env vars */
547 static void udhcp_run_script(struct dhcp_packet
*packet
, const char *name
)
552 envp
= fill_envp(packet
);
555 log1("Executing %s %s", client_config
.script
, name
);
556 argv
[0] = (char*) client_config
.script
;
557 argv
[1] = (char*) name
;
559 spawn_and_wait(argv
);
561 for (curr
= envp
; *curr
; curr
++) {
563 bb_unsetenv_and_free(*curr
);
569 /*** Sending/receiving packets ***/
571 static ALWAYS_INLINE
uint32_t random_xid(void)
576 /* Initialize the packet with the proper defaults */
577 static void init_packet(struct dhcp_packet
*packet
, char type
)
581 /* Fill in: op, htype, hlen, cookie fields; message type option: */
582 udhcp_init_header(packet
, type
);
584 packet
->xid
= random_xid();
586 client_config
.last_secs
= monotonic_sec();
587 if (client_config
.first_secs
== 0)
588 client_config
.first_secs
= client_config
.last_secs
;
589 secs
= client_config
.last_secs
- client_config
.first_secs
;
590 packet
->secs
= htons(secs
);
592 memcpy(packet
->chaddr
, client_config
.client_mac
, 6);
593 if (client_config
.clientid
)
594 udhcp_add_binary_option(packet
, client_config
.clientid
);
597 static void add_client_options(struct dhcp_packet
*packet
)
601 len
= sizeof(struct ip_udp_dhcp_packet
);
602 if (client_config
.client_mtu
== 0 ||
603 client_config
.client_mtu
> len
)
604 udhcp_add_simple_option(packet
, DHCP_MAX_SIZE
, htons(len
));
606 /* Add a "param req" option with the list of options we'd like to have
607 * from stubborn DHCP servers. Pull the data from the struct in common.c.
608 * No bounds checking because it goes towards the head of the packet. */
609 end
= udhcp_end_option(packet
->options
);
611 for (i
= 1; i
< DHCP_END
; i
++) {
612 if (client_config
.opt_mask
[i
>> 3] & (1 << (i
& 7))) {
613 packet
->options
[end
+ OPT_DATA
+ len
] = i
;
618 packet
->options
[end
+ OPT_CODE
] = DHCP_PARAM_REQ
;
619 packet
->options
[end
+ OPT_LEN
] = len
;
620 packet
->options
[end
+ OPT_DATA
+ len
] = DHCP_END
;
623 if (client_config
.vendorclass
)
624 udhcp_add_binary_option(packet
, client_config
.vendorclass
);
625 if (client_config
.hostname
)
626 udhcp_add_binary_option(packet
, client_config
.hostname
);
627 if (client_config
.fqdn
)
628 udhcp_add_binary_option(packet
, client_config
.fqdn
);
630 /* Request broadcast replies if we have no IP addr */
631 if ((option_mask32
& OPT_B
) && packet
->ciaddr
== 0)
632 packet
->flags
|= htons(BROADCAST_FLAG
);
634 /* Request broadcast replies if we have no IP addr */
635 if ((option_mask32
& OPT_B
) && packet
->ciaddr
== 0)
636 packet
->flags
|= htons(BROADCAST_FLAG
);
638 /* Add -x options if any */
640 struct option_set
*curr
= client_config
.options
;
642 udhcp_add_binary_option(packet
, curr
->data
);
645 // if (client_config.sname)
646 // strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
647 // if (client_config.boot_file)
648 // strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
651 // This will be needed if we remove -V VENDOR_STR in favor of
652 // -x vendor:VENDOR_STR
653 //if (!udhcp_find_option(packet.options, DHCP_VENDOR))
654 // /* not set, set the default vendor ID */
655 // ...add (DHCP_VENDOR, "udhcp "BB_VER) opt...
659 * 4.4.4 Use of broadcast and unicast
661 * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
662 * messages, unless the client knows the address of a DHCP server.
663 * The client unicasts DHCPRELEASE messages to the server. Because
664 * the client is declining the use of the IP address supplied by the server,
665 * the client broadcasts DHCPDECLINE messages.
667 * When the DHCP client knows the address of a DHCP server, in either
668 * INIT or REBOOTING state, the client may use that address
669 * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
670 * The client may also use unicast to send DHCPINFORM messages
671 * to a known DHCP server. If the client receives no response to DHCP
672 * messages sent to the IP address of a known DHCP server, the DHCP
673 * client reverts to using the IP broadcast address.
676 static int raw_bcast_from_client_config_ifindex(struct dhcp_packet
*packet
)
678 return udhcp_send_raw_packet(packet
,
679 /*src*/ INADDR_ANY
, CLIENT_PORT
,
680 /*dst*/ INADDR_BROADCAST
, SERVER_PORT
, MAC_BCAST_ADDR
,
681 client_config
.ifindex
);
684 /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
685 /* NOINLINE: limit stack usage in caller */
686 static NOINLINE
int send_discover(uint32_t xid
, uint32_t requested
)
688 struct dhcp_packet packet
;
691 /* Fill in: op, htype, hlen, cookie, chaddr fields,
692 * random xid field (we override it below),
693 * client-id option (unless -C), message type option:
695 init_packet(&packet
, DHCPDISCOVER
);
699 udhcp_add_simple_option(&packet
, DHCP_REQUESTED_IP
, requested
);
701 /* Add options: maxsize,
702 * optionally: hostname, fqdn, vendorclass,
703 * "param req" option according to -O, options specified with -x
705 add_client_options(&packet
);
708 bb_info_msg("Sending discover...");
709 return raw_bcast_from_client_config_ifindex(&packet
);
712 /* Broadcast a DHCP request message */
713 /* RFC 2131 3.1 paragraph 3:
714 * "The client _broadcasts_ a DHCPREQUEST message..."
716 /* NOINLINE: limit stack usage in caller */
717 static NOINLINE
int send_select(uint32_t xid
, uint32_t server
, uint32_t requested
)
719 struct dhcp_packet packet
;
723 * RFC 2131 4.3.2 DHCPREQUEST message
725 * If the DHCPREQUEST message contains a 'server identifier'
726 * option, the message is in response to a DHCPOFFER message.
727 * Otherwise, the message is a request to verify or extend an
728 * existing lease. If the client uses a 'client identifier'
729 * in a DHCPREQUEST message, it MUST use that same 'client identifier'
730 * in all subsequent messages. If the client included a list
731 * of requested parameters in a DHCPDISCOVER message, it MUST
732 * include that list in all subsequent messages.
734 /* Fill in: op, htype, hlen, cookie, chaddr fields,
735 * random xid field (we override it below),
736 * client-id option (unless -C), message type option:
738 init_packet(&packet
, DHCPREQUEST
);
741 udhcp_add_simple_option(&packet
, DHCP_REQUESTED_IP
, requested
);
743 udhcp_add_simple_option(&packet
, DHCP_SERVER_ID
, server
);
745 /* Add options: maxsize,
746 * optionally: hostname, fqdn, vendorclass,
747 * "param req" option according to -O, and options specified with -x
749 add_client_options(&packet
);
751 addr
.s_addr
= requested
;
752 bb_info_msg("Sending select for %s...", inet_ntoa(addr
));
753 return raw_bcast_from_client_config_ifindex(&packet
);
756 /* Unicast or broadcast a DHCP renew message */
757 /* NOINLINE: limit stack usage in caller */
758 static NOINLINE
int send_renew(uint32_t xid
, uint32_t server
, uint32_t ciaddr
)
760 struct dhcp_packet packet
;
763 * RFC 2131 4.3.2 DHCPREQUEST message
765 * DHCPREQUEST generated during RENEWING state:
767 * 'server identifier' MUST NOT be filled in, 'requested IP address'
768 * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
769 * client's IP address. In this situation, the client is completely
770 * configured, and is trying to extend its lease. This message will
771 * be unicast, so no relay agents will be involved in its
772 * transmission. Because 'giaddr' is therefore not filled in, the
773 * DHCP server will trust the value in 'ciaddr', and use it when
774 * replying to the client.
776 /* Fill in: op, htype, hlen, cookie, chaddr fields,
777 * random xid field (we override it below),
778 * client-id option (unless -C), message type option:
780 init_packet(&packet
, DHCPREQUEST
);
783 packet
.ciaddr
= ciaddr
;
785 /* Add options: maxsize,
786 * optionally: hostname, fqdn, vendorclass,
787 * "param req" option according to -O, and options specified with -x
789 add_client_options(&packet
);
791 bb_info_msg("Sending renew...");
793 return udhcp_send_kernel_packet(&packet
,
795 server
, SERVER_PORT
);
796 return raw_bcast_from_client_config_ifindex(&packet
);
799 #if ENABLE_FEATURE_UDHCPC_ARPING
800 /* Broadcast a DHCP decline message */
801 /* NOINLINE: limit stack usage in caller */
802 static NOINLINE
int send_decline(/*uint32_t xid,*/ uint32_t server
, uint32_t requested
)
804 struct dhcp_packet packet
;
806 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
807 * client-id option (unless -C), message type option:
809 init_packet(&packet
, DHCPDECLINE
);
812 /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
813 * but in case the server is buggy and wants DHCPDECLINE's xid
814 * to match the xid which started entire handshake,
815 * we use the same xid we used in initial DHCPDISCOVER:
819 /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
820 udhcp_add_simple_option(&packet
, DHCP_REQUESTED_IP
, requested
);
822 udhcp_add_simple_option(&packet
, DHCP_SERVER_ID
, server
);
824 bb_info_msg("Sending decline...");
825 return raw_bcast_from_client_config_ifindex(&packet
);
829 /* Unicast a DHCP release message */
830 static int send_release(uint32_t server
, uint32_t ciaddr
)
832 struct dhcp_packet packet
;
834 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
835 * client-id option (unless -C), message type option:
837 init_packet(&packet
, DHCPRELEASE
);
839 /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
840 packet
.ciaddr
= ciaddr
;
842 udhcp_add_simple_option(&packet
, DHCP_SERVER_ID
, server
);
844 bb_info_msg("Sending release...");
845 return udhcp_send_kernel_packet(&packet
, ciaddr
, CLIENT_PORT
, server
, SERVER_PORT
);
848 /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
849 /* NOINLINE: limit stack usage in caller */
850 static NOINLINE
int udhcp_recv_raw_packet(struct dhcp_packet
*dhcp_pkt
, int fd
)
853 struct ip_udp_dhcp_packet packet
;
855 unsigned char cmsgbuf
[CMSG_LEN(sizeof(struct tpacket_auxdata
))];
858 struct cmsghdr
*cmsg
;
860 /* used to use just safe_read(fd, &packet, sizeof(packet))
861 * but we need to check for TP_STATUS_CSUMNOTREADY :(
863 iov
.iov_base
= &packet
;
864 iov
.iov_len
= sizeof(packet
);
865 memset(&msg
, 0, sizeof(msg
));
868 msg
.msg_control
= cmsgbuf
;
869 msg
.msg_controllen
= sizeof(cmsgbuf
);
871 bytes
= recvmsg(fd
, &msg
, 0);
875 log1("Packet read error, ignoring");
876 /* NB: possible down interface, etc. Caller should pause. */
877 return bytes
; /* returns -1 */
882 if (bytes
< (int) (sizeof(packet
.ip
) + sizeof(packet
.udp
))) {
883 log1("Packet is too short, ignoring");
887 if (bytes
< ntohs(packet
.ip
.tot_len
)) {
888 /* packet is bigger than sizeof(packet), we did partial read */
889 log1("Oversized packet, ignoring");
893 /* ignore any extra garbage bytes */
894 bytes
= ntohs(packet
.ip
.tot_len
);
896 /* make sure its the right packet for us, and that it passes sanity checks */
897 if (packet
.ip
.protocol
!= IPPROTO_UDP
898 || packet
.ip
.version
!= IPVERSION
899 || packet
.ip
.ihl
!= (sizeof(packet
.ip
) >> 2)
900 || packet
.udp
.dest
!= htons(CLIENT_PORT
)
901 /* || bytes > (int) sizeof(packet) - can't happen */
902 || ntohs(packet
.udp
.len
) != (uint16_t)(bytes
- sizeof(packet
.ip
))
904 log1("Unrelated/bogus packet, ignoring");
908 /* verify IP checksum */
909 check
= packet
.ip
.check
;
911 if (check
!= inet_cksum((uint16_t *)&packet
.ip
, sizeof(packet
.ip
))) {
912 log1("Bad IP header checksum, ignoring");
916 for (cmsg
= CMSG_FIRSTHDR(&msg
); cmsg
; cmsg
= CMSG_NXTHDR(&msg
, cmsg
)) {
917 if (cmsg
->cmsg_level
== SOL_PACKET
918 && cmsg
->cmsg_type
== PACKET_AUXDATA
920 /* some VMs don't checksum UDP and TCP data
921 * they send to the same physical machine,
922 * here we detect this case:
924 struct tpacket_auxdata
*aux
= (void *)CMSG_DATA(cmsg
);
925 if (aux
->tp_status
& TP_STATUS_CSUMNOTREADY
)
926 goto skip_udp_sum_check
;
930 /* verify UDP checksum. IP header has to be modified for this */
931 memset(&packet
.ip
, 0, offsetof(struct iphdr
, protocol
));
932 /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
933 packet
.ip
.tot_len
= packet
.udp
.len
; /* yes, this is needed */
934 check
= packet
.udp
.check
;
935 packet
.udp
.check
= 0;
936 if (check
&& check
!= inet_cksum((uint16_t *)&packet
, bytes
)) {
937 log1("Packet with bad UDP checksum received, ignoring");
942 if (packet
.data
.cookie
!= htonl(DHCP_MAGIC
)) {
943 bb_info_msg("Packet with bad magic, ignoring");
947 log1("Received a packet");
948 udhcp_dump_packet(&packet
.data
);
950 bytes
-= sizeof(packet
.ip
) + sizeof(packet
.udp
);
951 memcpy(dhcp_pkt
, &packet
.data
, bytes
);
958 static int sockfd
= -1;
960 #define LISTEN_NONE 0
961 #define LISTEN_KERNEL 1
963 static smallint listen_mode
;
965 /* initial state: (re)start DHCP negotiation */
966 #define INIT_SELECTING 0
967 /* discover was sent, DHCPOFFER reply received */
969 /* select/renew was sent, DHCPACK reply received */
971 /* half of lease passed, want to renew it by sending unicast renew requests */
973 /* renew requests were not answered, lease is almost over, send broadcast renew */
975 /* manually requested renew (SIGUSR1) */
976 #define RENEW_REQUESTED 5
977 /* release, possibly manually requested (SIGUSR2) */
979 static smallint state
;
981 static int udhcp_raw_socket(int ifindex
)
984 struct sockaddr_ll sock
;
989 * I've selected not to see LL header, so BPF doesn't see it, too.
990 * The filter may also pass non-IP and non-ARP packets, but we do
991 * a more complete check when receiving the message in userspace.
993 * and filter shamelessly stolen from:
995 * http://www.flamewarmaster.de/software/dhcpclient/
997 * There are a few other interesting ideas on that page (look under
998 * "Motivation"). Use of netlink events is most interesting. Think
999 * of various network servers listening for events and reconfiguring.
1000 * That would obsolete sending HUP signals and/or make use of restarts.
1002 * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
1005 * TODO: make conditional?
1007 static const struct sock_filter filter_instr
[] = {
1008 /* load 9th byte (protocol) */
1009 BPF_STMT(BPF_LD
|BPF_B
|BPF_ABS
, 9),
1010 /* jump to L1 if it is IPPROTO_UDP, else to L4 */
1011 BPF_JUMP(BPF_JMP
|BPF_JEQ
|BPF_K
, IPPROTO_UDP
, 0, 6),
1012 /* L1: load halfword from offset 6 (flags and frag offset) */
1013 BPF_STMT(BPF_LD
|BPF_H
|BPF_ABS
, 6),
1014 /* jump to L4 if any bits in frag offset field are set, else to L2 */
1015 BPF_JUMP(BPF_JMP
|BPF_JSET
|BPF_K
, 0x1fff, 4, 0),
1016 /* L2: skip IP header (load index reg with header len) */
1017 BPF_STMT(BPF_LDX
|BPF_B
|BPF_MSH
, 0),
1018 /* load udp destination port from halfword[header_len + 2] */
1019 BPF_STMT(BPF_LD
|BPF_H
|BPF_IND
, 2),
1020 /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
1021 BPF_JUMP(BPF_JMP
|BPF_JEQ
|BPF_K
, 68, 0, 1),
1022 /* L3: accept packet */
1023 BPF_STMT(BPF_RET
|BPF_K
, 0xffffffff),
1024 /* L4: discard packet */
1025 BPF_STMT(BPF_RET
|BPF_K
, 0),
1027 static const struct sock_fprog filter_prog
= {
1028 .len
= sizeof(filter_instr
) / sizeof(filter_instr
[0]),
1029 /* casting const away: */
1030 .filter
= (struct sock_filter
*) filter_instr
,
1033 log1("Opening raw socket on ifindex %d", ifindex
); //log2?
1035 fd
= xsocket(PF_PACKET
, SOCK_DGRAM
, htons(ETH_P_IP
));
1036 log1("Got raw socket fd"); //log2?
1038 sock
.sll_family
= AF_PACKET
;
1039 sock
.sll_protocol
= htons(ETH_P_IP
);
1040 sock
.sll_ifindex
= ifindex
;
1041 xbind(fd
, (struct sockaddr
*) &sock
, sizeof(sock
));
1043 if (CLIENT_PORT
== 68) {
1044 /* Use only if standard port is in use */
1045 /* Ignoring error (kernel may lack support for this) */
1046 if (setsockopt(fd
, SOL_SOCKET
, SO_ATTACH_FILTER
, &filter_prog
,
1047 sizeof(filter_prog
)) >= 0)
1048 log1("Attached filter to raw socket fd"); // log?
1051 if (setsockopt(fd
, SOL_PACKET
, PACKET_AUXDATA
,
1052 &const_int_1
, sizeof(int)) < 0
1054 if (errno
!= ENOPROTOOPT
)
1055 log1("Can't set PACKET_AUXDATA on raw socket");
1058 log1("Created raw socket");
1063 static void change_listen_mode(int new_mode
)
1065 log1("Entering listen mode: %s",
1066 new_mode
!= LISTEN_NONE
1067 ? (new_mode
== LISTEN_KERNEL
? "kernel" : "raw")
1071 listen_mode
= new_mode
;
1076 if (new_mode
== LISTEN_KERNEL
)
1077 sockfd
= udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT
, client_config
.interface
);
1078 else if (new_mode
!= LISTEN_NONE
)
1079 sockfd
= udhcp_raw_socket(client_config
.ifindex
);
1080 /* else LISTEN_NONE: sockfd stays closed */
1083 /* Called only on SIGUSR1 */
1084 static void perform_renew(void)
1086 bb_info_msg("Performing a DHCP renew");
1089 change_listen_mode(LISTEN_RAW
); // zzz
1092 // state = RENEW_REQUESTED; // zzz
1094 case RENEW_REQUESTED
: /* impatient are we? fine, square 1 */
1097 change_listen_mode(LISTEN_RAW
);
1098 state
= INIT_SELECTING
;
1100 case INIT_SELECTING
:
1105 static void perform_release(uint32_t server_addr
, uint32_t requested_ip
)
1107 char buffer
[sizeof("255.255.255.255")];
1108 struct in_addr temp_addr
;
1110 /* send release packet */
1111 if (state
== BOUND
|| state
== RENEWING
|| state
== REBINDING
) {
1112 temp_addr
.s_addr
= server_addr
;
1113 strcpy(buffer
, inet_ntoa(temp_addr
));
1114 temp_addr
.s_addr
= requested_ip
;
1115 bb_info_msg("Unicasting a release of %s to %s",
1116 inet_ntoa(temp_addr
), buffer
);
1117 send_release(server_addr
, requested_ip
); /* unicast */
1118 udhcp_run_script(NULL
, "deconfig");
1120 bb_info_msg("Entering released state");
1122 change_listen_mode(LISTEN_NONE
);
1126 static uint8_t* alloc_dhcp_option(int code
, const char *str
, int extra
)
1129 int len
= strnlen(str
, 255);
1130 storage
= xzalloc(len
+ extra
+ OPT_DATA
);
1131 storage
[OPT_CODE
] = code
;
1132 storage
[OPT_LEN
] = len
+ extra
;
1133 memcpy(storage
+ extra
+ OPT_DATA
, str
, len
);
1138 static void client_background(void)
1141 logmode
&= ~LOGMODE_STDIO
;
1142 /* rewrite pidfile, as our pid is different now */
1143 write_pidfile(client_config
.pidfile
);
1147 //usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
1148 //usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
1150 //usage:# define IF_UDHCP_VERBOSE(...)
1152 //usage:#define udhcpc_trivial_usage
1153 //usage: "[-fbnq"IF_UDHCP_VERBOSE("v")"oCRB] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]\n"
1154 //usage: " [-V VENDOR] [-x OPT:VAL]... [-O OPT]..." IF_FEATURE_UDHCP_PORT(" [-P N]")
1155 //usage:#define udhcpc_full_usage "\n"
1156 //usage: IF_LONG_OPTS(
1157 //usage: "\n -i,--interface IFACE Interface to use (default eth0)"
1158 //usage: "\n -p,--pidfile FILE Create pidfile"
1159 //usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
1160 //usage: "\n -B,--broadcast Request broadcast replies"
1161 //usage: "\n -t,--retries N Send up to N discover packets"
1162 //usage: "\n -T,--timeout N Pause between packets (default 3 seconds)"
1163 //usage: "\n -A,--tryagain N Wait N seconds after failure (default 20)"
1164 //usage: "\n -f,--foreground Run in foreground"
1165 //usage: USE_FOR_MMU(
1166 //usage: "\n -b,--background Background if lease is not obtained"
1168 //usage: "\n -n,--now Exit if lease is not obtained"
1169 //usage: "\n -q,--quit Exit after obtaining lease"
1170 //usage: "\n -R,--release Release IP on exit"
1171 //usage: "\n -S,--syslog Log to syslog too"
1172 //usage: IF_FEATURE_UDHCP_PORT(
1173 //usage: "\n -P,--client-port N Use port N (default 68)"
1175 //usage: IF_FEATURE_UDHCPC_ARPING(
1176 //usage: "\n -a,--arping Use arping to validate offered address"
1178 //usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
1179 //usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
1180 //usage: "\n -r,--request IP Request this IP address"
1181 //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
1182 //usage: "\n Examples of string, numeric, and hex byte opts:"
1183 //usage: "\n -x hostname:bbox - option 12"
1184 //usage: "\n -x lease:3600 - option 51 (lease time)"
1185 //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
1186 //usage: "\n -F,--fqdn NAME Ask server to update DNS mapping for NAME"
1187 //usage: "\n -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')"
1188 //usage: "\n -C,--clientid-none Don't send MAC as client identifier"
1189 //usage: IF_UDHCP_VERBOSE(
1190 //usage: "\n -v Verbose"
1193 //usage: IF_NOT_LONG_OPTS(
1194 //usage: "\n -i IFACE Interface to use (default eth0)"
1195 //usage: "\n -p FILE Create pidfile"
1196 //usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
1197 //usage: "\n -B Request broadcast replies"
1198 //usage: "\n -t N Send up to N discover packets"
1199 //usage: "\n -T N Pause between packets (default 3 seconds)"
1200 //usage: "\n -A N Wait N seconds (default 20) after failure"
1201 //usage: "\n -f Run in foreground"
1202 //usage: USE_FOR_MMU(
1203 //usage: "\n -b Background if lease is not obtained"
1205 //usage: "\n -n Exit if lease is not obtained"
1206 //usage: "\n -q Exit after obtaining lease"
1207 //usage: "\n -R Release IP on exit"
1208 //usage: "\n -S Log to syslog too"
1209 //usage: IF_FEATURE_UDHCP_PORT(
1210 //usage: "\n -P N Use port N (default 68)"
1212 //usage: IF_FEATURE_UDHCPC_ARPING(
1213 //usage: "\n -a Use arping to validate offered address"
1215 //usage: "\n -O OPT Request option OPT from server (cumulative)"
1216 //usage: "\n -o Don't request any options (unless -O is given)"
1217 //usage: "\n -r IP Request this IP address"
1218 //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
1219 //usage: "\n Examples of string, numeric, and hex byte opts:"
1220 //usage: "\n -x hostname:bbox - option 12"
1221 //usage: "\n -x lease:3600 - option 51 (lease time)"
1222 //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
1223 //usage: "\n -F NAME Ask server to update DNS mapping for NAME"
1224 //usage: "\n -H,-h NAME Send NAME as client hostname (default none)"
1225 //usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
1226 //usage: "\n -C Don't send MAC as client identifier"
1227 //usage: IF_UDHCP_VERBOSE(
1228 //usage: "\n -v Verbose"
1231 //usage: "\nSignals:"
1232 //usage: "\n USR1 Renew current lease"
1233 //usage: "\n USR2 Release current lease"
1236 int udhcpc_main(int argc
, char **argv
) MAIN_EXTERNALLY_VISIBLE
;
1237 int udhcpc_main(int argc UNUSED_PARAM
, char **argv
)
1239 uint8_t *temp
, *message
;
1240 const char *str_V
, *str_h
, *str_F
, *str_r
;
1241 IF_FEATURE_UDHCP_PORT(char *str_P
;)
1242 void *clientid_mac_ptr
;
1243 llist_t
*list_O
= NULL
;
1244 llist_t
*list_x
= NULL
;
1245 int tryagain_timeout
= 20;
1246 int discover_timeout
= 3;
1247 int discover_retries
= 5;
1248 uint32_t server_addr
= server_addr
; /* for compiler */
1249 uint32_t requested_ip
= 0;
1250 uint32_t xid
= xid
; /* for compiler */
1252 int timeout
; /* must be signed */
1253 unsigned already_waited_sec
;
1259 /* Default options */
1260 IF_FEATURE_UDHCP_PORT(SERVER_PORT
= 67;)
1261 IF_FEATURE_UDHCP_PORT(CLIENT_PORT
= 68;)
1262 client_config
.interface
= "eth0";
1263 client_config
.script
= CONFIG_UDHCPC_DEFAULT_SCRIPT
;
1264 str_V
= "udhcp "BB_VER
;
1266 /* Parse command line */
1267 /* O,x: list; -T,-t,-A take numeric param */
1268 opt_complementary
= "O::x::T+:t+:A+" IF_UDHCP_VERBOSE(":vv") ;
1270 IF_LONG_OPTS(applet_long_options
= udhcpc_longopts
;)
1271 opt
= getopt32(argv
, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:fB"
1274 IF_FEATURE_UDHCPC_ARPING("a")
1275 IF_FEATURE_UDHCP_PORT("P:")
1277 , &str_V
, &str_h
, &str_h
, &str_F
1278 , &client_config
.interface
, &client_config
.pidfile
, &str_r
/* i,p */
1279 , &client_config
.script
/* s */
1280 , &discover_timeout
, &discover_retries
, &tryagain_timeout
/* T,t,A */
1283 IF_FEATURE_UDHCP_PORT(, &str_P
)
1284 IF_UDHCP_VERBOSE(, &dhcp_verbose
)
1286 if (opt
& (OPT_h
|OPT_H
)) {
1288 bb_error_msg("option -h NAME is deprecated, use -x hostname:NAME");
1289 client_config
.hostname
= alloc_dhcp_option(DHCP_HOST_NAME
, str_h
, 0);
1292 /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
1293 client_config
.fqdn
= alloc_dhcp_option(DHCP_FQDN
, str_F
, 3);
1294 /* Flag bits: 0000NEOS
1295 * S: 1 = Client requests server to update A RR in DNS as well as PTR
1296 * O: 1 = Server indicates to client that DNS has been updated regardless
1297 * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
1298 * not "host.domain.com". Format 0 is obsolete.
1299 * N: 1 = Client requests server to not update DNS (S must be 0 then)
1300 * Two [0] bytes which follow are deprecated and must be 0.
1302 client_config
.fqdn
[OPT_DATA
+ 0] = 0x1;
1303 /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
1304 /*client_config.fqdn[OPT_DATA + 2] = 0; */
1307 requested_ip
= inet_addr(str_r
);
1308 #if ENABLE_FEATURE_UDHCP_PORT
1310 CLIENT_PORT
= xatou16(str_P
);
1311 SERVER_PORT
= CLIENT_PORT
- 1;
1315 char *optstr
= llist_pop(&list_O
);
1316 unsigned n
= bb_strtou(optstr
, NULL
, 0);
1317 if (errno
|| n
> 254) {
1318 n
= udhcp_option_idx(optstr
);
1319 n
= dhcp_optflags
[n
].code
;
1321 client_config
.opt_mask
[n
>> 3] |= 1 << (n
& 7);
1323 if (!(opt
& OPT_o
)) {
1325 for (i
= 0; (n
= dhcp_optflags
[i
].code
) != 0; i
++) {
1326 if (dhcp_optflags
[i
].flags
& OPTION_REQ
) {
1327 client_config
.opt_mask
[n
>> 3] |= 1 << (n
& 7);
1332 char *optstr
= llist_pop(&list_x
);
1333 char *colon
= strchr(optstr
, ':');
1336 /* now it looks similar to udhcpd's config file line:
1337 * "optname optval", using the common routine: */
1338 udhcp_str2optset(optstr
, &client_config
.options
);
1341 if (opt
& OPT_m
) // zzz
1344 if (udhcp_read_interface(client_config
.interface
,
1345 &client_config
.ifindex
,
1347 client_config
.client_mac
,
1348 &client_config
.client_mtu
)
1353 clientid_mac_ptr
= NULL
;
1354 if (!(opt
& OPT_C
) && !udhcp_find_option(client_config
.options
, DHCP_CLIENT_ID
)) {
1355 /* not suppressed and not set, set the default client ID */
1356 client_config
.clientid
= alloc_dhcp_option(DHCP_CLIENT_ID
, "", 7);
1357 client_config
.clientid
[OPT_DATA
] = 1; /* type: ethernet */
1358 clientid_mac_ptr
= client_config
.clientid
+ OPT_DATA
+1;
1359 memcpy(clientid_mac_ptr
, client_config
.client_mac
, 6);
1361 if (str_V
[0] != '\0') {
1362 // can drop -V, str_V, client_config.vendorclass,
1363 // but need to add "vendor" to the list of recognized
1364 // string opts for this to work;
1365 // and need to tweak add_client_options() too...
1366 // ...so the question is, should we?
1367 //bb_error_msg("option -V VENDOR is deprecated, use -x vendor:VENDOR");
1368 client_config
.vendorclass
= alloc_dhcp_option(DHCP_VENDOR
, str_V
, 0);
1372 /* on NOMMU reexec (i.e., background) early */
1373 if (!(opt
& OPT_f
)) {
1374 bb_daemonize_or_rexec(0 /* flags */, argv
);
1375 logmode
= LOGMODE_NONE
;
1379 openlog(applet_name
, LOG_PID
, LOG_DAEMON
);
1380 logmode
|= LOGMODE_SYSLOG
;
1383 /* Make sure fd 0,1,2 are open */
1384 bb_sanitize_stdio();
1385 /* Equivalent of doing a fflush after every \n */
1387 /* Create pidfile */
1388 write_pidfile(client_config
.pidfile
);
1389 /* Goes to stdout (unless NOMMU) and possibly syslog */
1390 bb_info_msg("%s (v"BB_VER
") started", applet_name
);
1391 /* Set up the signal pipe */
1393 /* We want random_xid to be random... */
1394 srand(monotonic_us());
1396 state
= INIT_SELECTING
;
1397 udhcp_run_script(NULL
, "deconfig");
1398 change_listen_mode(LISTEN_RAW
);
1401 already_waited_sec
= 0;
1403 /* Main event loop. select() waits on signal pipe and possibly
1405 * "continue" statements in code below jump to the top of the loop.
1409 struct dhcp_packet packet
;
1410 /* silence "uninitialized!" warning */
1411 unsigned timestamp_before_wait
= timestamp_before_wait
;
1413 //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
1415 /* Was opening raw or udp socket here
1416 * if (listen_mode != LISTEN_NONE && sockfd < 0),
1417 * but on fast network renew responses return faster
1418 * than we open sockets. Thus this code is moved
1419 * to change_listen_mode(). Thus we open listen socket
1420 * BEFORE we send renew request (see "case BOUND:"). */
1422 max_fd
= udhcp_sp_fd_set(&rfds
, sockfd
);
1424 tv
.tv_sec
= timeout
- already_waited_sec
;
1427 /* If we already timed out, fall through with retval = 0, else... */
1428 if ((int)tv
.tv_sec
> 0) {
1429 log1("Waiting on select %u seconds", (int)tv
.tv_sec
);
1430 timestamp_before_wait
= (unsigned)monotonic_sec();
1431 retval
= select(max_fd
+ 1, &rfds
, NULL
, NULL
, &tv
);
1433 /* EINTR? A signal was caught, don't panic */
1434 if (errno
== EINTR
) {
1435 already_waited_sec
+= (unsigned)monotonic_sec() - timestamp_before_wait
;
1438 /* Else: an error occured, panic! */
1439 bb_perror_msg_and_die("select");
1443 /* If timeout dropped to zero, time to become active:
1444 * resend discover/renew/whatever
1447 /* When running on a bridge, the ifindex may have changed
1448 * (e.g. if member interfaces were added/removed
1449 * or if the status of the bridge changed).
1450 * Refresh ifindex and client_mac:
1452 if (udhcp_read_interface(client_config
.interface
,
1453 &client_config
.ifindex
,
1455 client_config
.client_mac
,
1456 &client_config
.client_mtu
)
1458 goto ret0
; /* iface is gone? */
1460 if (clientid_mac_ptr
)
1461 memcpy(clientid_mac_ptr
, client_config
.client_mac
, 6);
1463 /* We will restart the wait in any case */
1464 already_waited_sec
= 0;
1467 case INIT_SELECTING
:
1468 if (!discover_retries
|| packet_num
< discover_retries
) {
1469 if (packet_num
== 0)
1472 send_discover(xid
, requested_ip
);
1473 timeout
= discover_timeout
;
1478 udhcp_run_script(NULL
, "leasefail");
1479 #if BB_MMU /* -b is not supported on NOMMU */
1480 if (opt
& OPT_b
) { /* background if no lease */
1481 bb_info_msg("No lease, forking to background");
1482 client_background();
1483 /* do not background again! */
1484 opt
= ((opt
& ~OPT_b
) | OPT_f
);
1487 if (opt
& OPT_n
) { /* abort if no lease */
1488 bb_info_msg("No lease, failing");
1492 /* wait before trying again */
1493 timeout
= tryagain_timeout
;
1497 if (!discover_retries
|| packet_num
< discover_retries
) {
1498 /* send broadcast select packet */
1499 send_select(xid
, server_addr
, requested_ip
);
1500 timeout
= discover_timeout
;
1504 /* Timed out, go back to init state.
1505 * "discover...select...discover..." loops
1506 * were seen in the wild. Treat them similarly
1507 * to "no response to discover" case */
1508 change_listen_mode(LISTEN_RAW
);
1509 state
= INIT_SELECTING
;
1512 /* 1/2 lease passed, enter renewing state */
1514 client_config
.first_secs
= 0; /* make secs field count from 0 */
1515 change_listen_mode(LISTEN_RAW
); // was: LISTEN_KERNEL -- zzz
1516 log1("Entering renew state");
1517 /* fall right through */
1518 case RENEW_REQUESTED
: /* manual (SIGUSR1) renew */
1519 case_RENEW_REQUESTED
:
1522 /* send an unicast renew request */
1523 /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1524 * a new UDP socket for sending inside send_renew.
1525 * I hazard to guess existing listening socket
1526 * is somehow conflicting with it, but why is it
1527 * not deterministic then?! Strange.
1528 * Anyway, it does recover by eventually failing through
1529 * into INIT_SELECTING state.
1531 send_renew(xid
, server_addr
, requested_ip
);
1535 /* Timed out, enter rebinding state */
1536 log1("Entering rebinding state");
1538 /* fall right through */
1540 /* Switch to bcast receive */
1541 change_listen_mode(LISTEN_RAW
);
1542 /* Lease is *really* about to run out,
1543 * try to find DHCP server using broadcast */
1545 /* send a broadcast renew request */
1546 send_renew(xid
, 0 /*INADDR_ANY*/, requested_ip
);
1550 /* Timed out, enter init state */
1551 bb_info_msg("Lease lost, entering init state");
1552 udhcp_run_script(NULL
, "deconfig");
1553 state
= INIT_SELECTING
;
1554 client_config
.first_secs
= 0; /* make secs field count from 0 */
1555 /*timeout = 0; - already is */
1558 /* case RELEASED: */
1560 /* yah, I know, *you* say it would never happen */
1562 continue; /* back to main loop */
1563 } /* if select timed out */
1565 /* select() didn't timeout, something happened */
1567 /* Is it a signal? */
1568 /* note: udhcp_sp_read checks FD_ISSET before reading */
1569 switch (udhcp_sp_read(&rfds
)) {
1571 client_config
.first_secs
= 0; /* make secs field count from 0 */
1572 // already_waited_sec = 0; /* shibby - this broke tomato renew button */
1574 if (state
== RENEW_REQUESTED
)
1575 // if (timeout > tryagain_timeout) /* shibby - this broke tomato renew button */
1576 // timeout = tryagain_timeout; /* shibby - this broke tomato renew button */
1577 goto case_RENEW_REQUESTED
;
1578 /* Start things over */
1580 /* Kill any timeouts, user wants this to hurry along */
1584 perform_release(server_addr
, requested_ip
);
1588 bb_info_msg("Received SIGTERM");
1592 /* Is it a packet? */
1593 if (listen_mode
== LISTEN_NONE
|| !FD_ISSET(sockfd
, &rfds
))
1599 /* A packet is ready, read it */
1600 if (listen_mode
== LISTEN_KERNEL
)
1601 len
= udhcp_recv_kernel_packet(&packet
, sockfd
);
1603 len
= udhcp_recv_raw_packet(&packet
, sockfd
);
1605 /* Error is severe, reopen socket */
1606 bb_info_msg("Read error: %s, reopening socket", strerror(errno
));
1607 sleep(discover_timeout
); /* 3 seconds by default */
1608 change_listen_mode(listen_mode
); /* just close and reopen */
1610 /* If this packet will turn out to be unrelated/bogus,
1611 * we will go back and wait for next one.
1612 * Be sure timeout is properly decreased. */
1613 already_waited_sec
+= (unsigned)monotonic_sec() - timestamp_before_wait
;
1618 if (packet
.xid
!= xid
) {
1619 log1("xid %x (our is %x), ignoring packet",
1620 (unsigned)packet
.xid
, (unsigned)xid
);
1624 /* Ignore packets that aren't for us */
1625 if (packet
.hlen
!= 6
1626 || memcmp(packet
.chaddr
, client_config
.client_mac
, 6) != 0
1628 //FIXME: need to also check that last 10 bytes are zero
1629 log1("chaddr does not match, ignoring packet"); // log2?
1633 message
= udhcp_get_option(&packet
, DHCP_MESSAGE_TYPE
);
1634 if (message
== NULL
) {
1635 bb_error_msg("no message type option, ignoring packet");
1640 case INIT_SELECTING
:
1641 /* Must be a DHCPOFFER */
1642 if (*message
== DHCPOFFER
) {
1643 /* What exactly is server's IP? There are several values.
1644 * Example DHCP offer captured with tchdump:
1646 * 10.34.25.254:67 > 10.34.25.202:68 // IP header's src
1648 * Your-IP 10.34.25.202
1649 * Server-IP 10.34.32.125 // "next server" IP
1650 * Gateway-IP 10.34.25.254 // relay's address (if DHCP relays are in use)
1652 * DHCP-Message Option 53, length 1: Offer
1653 * Server-ID Option 54, length 4: 10.34.255.7 // "server ID"
1654 * Default-Gateway Option 3, length 4: 10.34.25.254 // router
1656 * We think that real server IP (one to use in renew/release)
1657 * is one in Server-ID option. But I am not 100% sure.
1658 * IP header's src and Gateway-IP (same in this example)
1660 * "Next server" and router are definitely wrong ones to use, though...
1662 temp
= udhcp_get_option(&packet
, DHCP_SERVER_ID
);
1664 bb_error_msg("no server ID, ignoring packet");
1666 /* still selecting - this server looks bad */
1668 /* it IS unaligned sometimes, don't "optimize" */
1669 move_from_unaligned32(server_addr
, temp
);
1670 /*xid = packet.xid; - already is */
1671 requested_ip
= packet
.yiaddr
;
1673 /* enter requesting state */
1677 already_waited_sec
= 0;
1682 case RENEW_REQUESTED
:
1684 if (*message
== DHCPACK
) {
1685 uint32_t lease_seconds
;
1686 struct in_addr temp_addr
;
1688 temp
= udhcp_get_option(&packet
, DHCP_LEASE_TIME
);
1690 bb_error_msg("no lease time with ACK, using 1 hour lease");
1691 lease_seconds
= 60 * 60;
1693 /* it IS unaligned sometimes, don't "optimize" */
1694 move_from_unaligned32(lease_seconds
, temp
);
1695 lease_seconds
= ntohl(lease_seconds
);
1696 /* paranoia: must not be too small and not prone to overflows */
1697 if (lease_seconds
< 0x10)
1698 lease_seconds
= 0x10;
1699 if (lease_seconds
>= 0x10000000)
1700 lease_seconds
= 0x0fffffff;
1702 #if ENABLE_FEATURE_UDHCPC_ARPING
1704 /* RFC 2131 3.1 paragraph 5:
1705 * "The client receives the DHCPACK message with configuration
1706 * parameters. The client SHOULD perform a final check on the
1707 * parameters (e.g., ARP for allocated network address), and notes
1708 * the duration of the lease specified in the DHCPACK message. At this
1709 * point, the client is configured. If the client detects that the
1710 * address is already in use (e.g., through the use of ARP),
1711 * the client MUST send a DHCPDECLINE message to the server and restarts
1712 * the configuration process..." */
1713 if (!arpping(packet
.yiaddr
,
1716 client_config
.client_mac
,
1717 client_config
.interface
)
1719 bb_info_msg("Offered address is in use "
1720 "(got ARP reply), declining");
1721 send_decline(/*xid,*/ server_addr
, packet
.yiaddr
);
1723 if (state
!= REQUESTING
)
1724 udhcp_run_script(NULL
, "deconfig");
1725 change_listen_mode(LISTEN_RAW
);
1726 state
= INIT_SELECTING
;
1727 client_config
.first_secs
= 0; /* make secs field count from 0 */
1729 timeout
= tryagain_timeout
;
1731 already_waited_sec
= 0;
1732 continue; /* back to main loop */
1736 /* enter bound state */
1737 timeout
= lease_seconds
/ 2;
1738 temp_addr
.s_addr
= packet
.yiaddr
;
1739 bb_info_msg("Lease of %s obtained, lease time %u",
1740 inet_ntoa(temp_addr
), (unsigned)lease_seconds
);
1741 requested_ip
= packet
.yiaddr
;
1742 udhcp_run_script(&packet
, state
== REQUESTING
? "bound" : "renew");
1745 change_listen_mode(LISTEN_NONE
);
1746 if (opt
& OPT_q
) { /* quit after lease */
1749 /* future renew failures should not exit (JM) */
1751 #if BB_MMU /* NOMMU case backgrounded earlier */
1752 if (!(opt
& OPT_f
)) {
1753 client_background();
1754 /* do not background again! */
1755 opt
= ((opt
& ~OPT_b
) | OPT_f
);
1758 /* make future renew packets use different xid */
1759 /* xid = random_xid(); ...but why bother? */
1760 already_waited_sec
= 0;
1761 continue; /* back to main loop */
1763 if (*message
== DHCPNAK
) {
1764 /* return to init state */
1765 bb_info_msg("Received DHCP NAK");
1766 udhcp_run_script(&packet
, "nak");
1767 if (state
!= REQUESTING
)
1768 udhcp_run_script(NULL
, "deconfig");
1769 change_listen_mode(LISTEN_RAW
);
1770 sleep(3); /* avoid excessive network traffic */
1771 state
= INIT_SELECTING
;
1772 client_config
.first_secs
= 0; /* make secs field count from 0 */
1776 already_waited_sec
= 0;
1779 /* case BOUND: - ignore all packets */
1780 /* case RELEASED: - ignore all packets */
1782 /* back to main loop */
1783 } /* for (;;) - main loop ends */
1786 if (opt
& OPT_R
) /* release on quit */
1787 perform_release(server_addr
, requested_ip
);
1790 /*if (client_config.pidfile) - remove_pidfile has its own check */
1791 remove_pidfile(client_config
.pidfile
);