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 <netinet/if_ether.h>
29 #include <netpacket/packet.h>
30 #include <linux/filter.h>
32 /* struct client_config_t client_config is in bb_common_bufsiz1 */
36 static const char udhcpc_longopts[] ALIGN1 =
37 "clientid-none\0" No_argument "C"
38 "vendorclass\0" Required_argument "V"
39 "hostname\0" Required_argument "H"
40 "fqdn\0" Required_argument "F"
41 "interface\0" Required_argument "i"
42 "now\0" No_argument "n"
43 "pidfile\0" Required_argument "p"
44 "quit\0" No_argument "q"
45 "release\0" No_argument "R"
46 "request\0" Required_argument "r"
47 "script\0" Required_argument "s"
48 "timeout\0" Required_argument "T"
49 "version\0" No_argument "v"
50 "retries\0" Required_argument "t"
51 "tryagain\0" Required_argument "A"
52 "syslog\0" No_argument "S"
53 "request-option\0" Required_argument "O"
54 "no-default-options\0" No_argument "o"
55 "foreground\0" No_argument "f"
56 "background\0" No_argument "b"
57 "broadcast\0" No_argument "B"
58 IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
59 IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
62 /* Must match getopt32 option string order */
85 /* The rest has variable bit positions, need to be clever */
87 USE_FOR_MMU( OPTBIT_b,)
88 IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
89 IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
90 USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
91 IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
92 IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
96 /*** Script execution code ***/
98 /* get a rough idea of how long an option will be (rounding up...) */
99 static const uint8_t len_of_option_as_string[] = {
100 [OPTION_IP ] = sizeof("255.255.255.255 "),
101 [OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2,
102 [OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "),
103 [OPTION_STRING ] = 1,
104 #if ENABLE_FEATURE_UDHCP_RFC3397
105 [OPTION_DNS_STRING ] = 1, /* unused */
106 /* Hmmm, this severely overestimates size if SIP_SERVERS option
107 * is in domain name form: N-byte option in binary form
108 * mallocs ~16*N bytes. But it is freed almost at once.
110 [OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "),
112 // [OPTION_BOOLEAN ] = sizeof("yes "),
113 [OPTION_U8 ] = sizeof("255 "),
114 [OPTION_U16 ] = sizeof("65535 "),
115 // [OPTION_S16 ] = sizeof("-32768 "),
116 [OPTION_U32 ] = sizeof("4294967295 "),
117 [OPTION_S32 ] = sizeof("-2147483684 "),
120 /* note: ip is a pointer to an IP in network order, possibly misaliged */
121 static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
123 return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
126 /* really simple implementation, just count the bits */
127 static int mton(uint32_t mask)
130 mask = ntohl(mask); /* 111110000-like bit pattern */
138 /* Create "opt_name=opt_value" string */
139 static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name)
141 unsigned upper_length;
142 int len, type, optlen;
145 /* option points to OPT_DATA, need to go back and get OPT_LEN */
146 len = option[OPT_LEN - OPT_DATA];
148 type = optflag->flags & OPTION_TYPE_MASK;
149 optlen = dhcp_option_lengths[type];
150 upper_length = len_of_option_as_string[type] * ((unsigned)len / (unsigned)optlen);
152 dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
153 dest += sprintf(ret, "%s=", opt_name);
155 while (len >= optlen) {
160 dest += sprint_nip(dest, "", option);
165 dest += sprint_nip(dest, "", option + ip_ofs);
167 // case OPTION_BOOLEAN:
168 // dest += sprintf(dest, *option ? "yes" : "no");
171 dest += sprintf(dest, "%u", *option);
176 move_from_unaligned16(val_u16, option);
177 dest += sprintf(dest, "%u", ntohs(val_u16));
183 move_from_unaligned32(val_u32, option);
184 dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
188 memcpy(dest, option, len);
190 return ret; /* Short circuit this case */
191 case OPTION_STATIC_ROUTES: {
192 /* Option binary format:
193 * mask [one byte, 0..32]
194 * ip [big endian, 0..4 bytes depending on mask]
195 * router [big endian, 4 bytes]
198 * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
200 const char *pfx = "";
202 while (len >= 1 + 4) { /* mask + 0-byte ip + router */
215 bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
216 while (--bytes >= 0) {
224 dest += sprint_nip(dest, pfx, (void*) &nip);
226 dest += sprintf(dest, "/%u ", mask);
228 dest += sprint_nip(dest, "", option);
235 #if ENABLE_FEATURE_UDHCP_RFC3397
236 case OPTION_DNS_STRING:
237 /* unpack option into dest; use ret for prefix (i.e., "optname=") */
238 dest = dname_dec(option, len, ret);
243 /* error. return "optname=" string */
245 case OPTION_SIP_SERVERS:
246 /* Option binary format:
248 * type=0: domain names, dns-compressed
253 if (option[-1] == 0) {
254 dest = dname_dec(option, len, ret);
260 if (option[-1] == 1) {
261 const char *pfx = "";
266 dest += sprint_nip(dest, pfx, option);
276 // TODO: it can be a list only if (optflag->flags & OPTION_LIST).
277 // Should we bail out/warn if we see multi-ip option which is
278 // not allowed to be such (for example, DHCP_BROADCAST)? -
279 if (len <= 0 /* || !(optflag->flags & OPTION_LIST) */)
287 /* put all the parameters into the environment */
288 static char **fill_envp(struct dhcp_packet *packet)
293 const char *opt_name;
295 uint8_t overload = 0;
297 #define BITMAP unsigned
298 #define BBITS (sizeof(BITMAP) * 8)
299 #define BMASK(i) (1 << (i & (sizeof(BITMAP) * 8 - 1)))
300 #define FOUND_OPTS(i) (found_opts[(unsigned)i / BBITS])
301 BITMAP found_opts[256 / BBITS];
303 memset(found_opts, 0, sizeof(found_opts));
305 /* We need 6 elements for:
307 * "ip=N.N.N.N" from packet->yiaddr
308 * "siaddr=IP" from packet->siaddr_nip (unless 0)
309 * "boot_file=FILE" from packet->file (unless overloaded)
310 * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded)
314 /* +1 element for each option, +2 for subnet option: */
316 /* note: do not search for "pad" (0) and "end" (255) options */
317 for (i = 1; i < 255; i++) {
318 temp = udhcp_get_option(packet, i);
320 if (i == DHCP_OPTION_OVERLOAD)
322 else if (i == DHCP_SUBNET)
323 envc++; /* for mton */
325 /*if (i != DHCP_MESSAGE_TYPE)*/
326 FOUND_OPTS(i) |= BMASK(i);
330 curr = envp = xzalloc(sizeof(envp[0]) * envc);
332 *curr = xasprintf("interface=%s", client_config.interface);
338 *curr = xmalloc(sizeof("ip=255.255.255.255"));
339 sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
342 opt_name = dhcp_option_strings;
345 uint8_t code = dhcp_optflags[i].code;
346 BITMAP *found_ptr = &FOUND_OPTS(code);
347 BITMAP found_mask = BMASK(code);
348 if (!(*found_ptr & found_mask))
350 *found_ptr &= ~found_mask; /* leave only unknown options */
351 temp = udhcp_get_option(packet, code);
352 *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name);
354 if (code == DHCP_SUBNET) {
355 /* Subnet option: make things like "$ip/$mask" possible */
357 move_from_unaligned32(subnet, temp);
358 *curr = xasprintf("mask=%d", mton(subnet));
362 opt_name += strlen(opt_name) + 1;
365 if (packet->siaddr_nip) {
366 *curr = xmalloc(sizeof("siaddr=255.255.255.255"));
367 sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
370 if (!(overload & FILE_FIELD) && packet->file[0]) {
371 /* watch out for invalid packets */
372 *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
375 if (!(overload & SNAME_FIELD) && packet->sname[0]) {
376 /* watch out for invalid packets */
377 *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
380 /* Handle unknown options */
381 for (i = 0; i < 256;) {
382 BITMAP bitmap = FOUND_OPTS(i);
387 if (bitmap & BMASK(i)) {
390 temp = udhcp_get_option(packet, i);
391 /* udhcp_get_option returns ptr to data portion,
392 * need to go back to get len
394 len = temp[-OPT_DATA + OPT_LEN];
395 *curr = xmalloc(sizeof("optNNN=") + 1 + len*2);
396 ofs = sprintf(*curr, "opt%u=", i);
397 bin2hex(*curr + ofs, (void*) temp, len)[0] = '\0';
405 /* Call a script with a par file and env vars */
406 static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
411 if (client_config.script == NULL)
414 envp = fill_envp(packet);
417 log1("Executing %s %s", client_config.script, name);
418 argv[0] = (char*) client_config.script;
419 argv[1] = (char*) name;
421 spawn_and_wait(argv);
423 for (curr = envp; *curr; curr++) {
425 bb_unsetenv_and_free(*curr);
431 /*** Sending/receiving packets ***/
433 static ALWAYS_INLINE uint32_t random_xid(void)
438 /* Initialize the packet with the proper defaults */
439 static void init_packet(struct dhcp_packet *packet, char type)
443 /* Fill in: op, htype, hlen, cookie fields; message type option: */
444 udhcp_init_header(packet, type);
446 packet->xid = random_xid();
448 client_config.last_secs = monotonic_sec();
449 if (client_config.first_secs == 0)
450 client_config.first_secs = client_config.last_secs;
451 secs = client_config.last_secs - client_config.first_secs;
452 packet->secs = htons(secs);
454 memcpy(packet->chaddr, client_config.client_mac, 6);
455 if (client_config.clientid)
456 udhcp_add_binary_option(packet, client_config.clientid);
459 static void add_client_options(struct dhcp_packet *packet)
464 udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
466 /* Add a "param req" option with the list of options we'd like to have
467 * from stubborn DHCP servers. Pull the data from the struct in common.c.
468 * No bounds checking because it goes towards the head of the packet. */
469 end = udhcp_end_option(packet->options);
471 for (i = 0; (c = dhcp_optflags[i].code) != 0; i++) {
472 if (( (dhcp_optflags[i].flags & OPTION_REQ)
473 && !client_config.no_default_options
475 || (client_config.opt_mask[c >> 3] & (1 << (c & 7)))
477 packet->options[end + OPT_DATA + len] = c;
482 packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
483 packet->options[end + OPT_LEN] = len;
484 packet->options[end + OPT_DATA + len] = DHCP_END;
487 if (client_config.vendorclass)
488 udhcp_add_binary_option(packet, client_config.vendorclass);
489 if (client_config.hostname)
490 udhcp_add_binary_option(packet, client_config.hostname);
491 if (client_config.fqdn)
492 udhcp_add_binary_option(packet, client_config.fqdn);
494 /* Request broadcast replies if we have no IP addr */
495 if ((option_mask32 & OPT_B) && packet->ciaddr == 0)
496 packet->flags |= htons(BROADCAST_FLAG);
498 /* Add -x options if any */
500 struct option_set *curr = client_config.options;
502 udhcp_add_binary_option(packet, curr->data);
505 // if (client_config.sname)
506 // strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
507 // if (client_config.boot_file)
508 // strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
513 * 4.4.4 Use of broadcast and unicast
515 * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
516 * messages, unless the client knows the address of a DHCP server.
517 * The client unicasts DHCPRELEASE messages to the server. Because
518 * the client is declining the use of the IP address supplied by the server,
519 * the client broadcasts DHCPDECLINE messages.
521 * When the DHCP client knows the address of a DHCP server, in either
522 * INIT or REBOOTING state, the client may use that address
523 * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
524 * The client may also use unicast to send DHCPINFORM messages
525 * to a known DHCP server. If the client receives no response to DHCP
526 * messages sent to the IP address of a known DHCP server, the DHCP
527 * client reverts to using the IP broadcast address.
530 static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet)
532 return udhcp_send_raw_packet(packet,
533 /*src*/ INADDR_ANY, CLIENT_PORT,
534 /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
535 client_config.ifindex);
538 /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
539 /* NOINLINE: limit stack usage in caller */
540 static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
542 struct dhcp_packet packet;
544 /* Fill in: op, htype, hlen, cookie, chaddr fields,
545 * random xid field (we override it below),
546 * client-id option (unless -C), message type option:
548 init_packet(&packet, DHCPDISCOVER);
552 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
554 /* Add options: maxsize,
555 * optionally: hostname, fqdn, vendorclass,
556 * "param req" option according to -O, options specified with -x
558 add_client_options(&packet);
560 bb_info_msg("Sending discover...");
561 return raw_bcast_from_client_config_ifindex(&packet);
564 /* Broadcast a DHCP request message */
565 /* RFC 2131 3.1 paragraph 3:
566 * "The client _broadcasts_ a DHCPREQUEST message..."
568 /* NOINLINE: limit stack usage in caller */
569 static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
571 struct dhcp_packet packet;
575 * RFC 2131 4.3.2 DHCPREQUEST message
577 * If the DHCPREQUEST message contains a 'server identifier'
578 * option, the message is in response to a DHCPOFFER message.
579 * Otherwise, the message is a request to verify or extend an
580 * existing lease. If the client uses a 'client identifier'
581 * in a DHCPREQUEST message, it MUST use that same 'client identifier'
582 * in all subsequent messages. If the client included a list
583 * of requested parameters in a DHCPDISCOVER message, it MUST
584 * include that list in all subsequent messages.
586 /* Fill in: op, htype, hlen, cookie, chaddr fields,
587 * random xid field (we override it below),
588 * client-id option (unless -C), message type option:
590 init_packet(&packet, DHCPREQUEST);
593 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
595 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
597 /* Add options: maxsize,
598 * optionally: hostname, fqdn, vendorclass,
599 * "param req" option according to -O, and options specified with -x
601 add_client_options(&packet);
603 addr.s_addr = requested;
604 bb_info_msg("Sending select for %s...", inet_ntoa(addr));
605 return raw_bcast_from_client_config_ifindex(&packet);
608 /* Unicast or broadcast a DHCP renew message */
609 /* NOINLINE: limit stack usage in caller */
610 static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
612 struct dhcp_packet packet;
615 * RFC 2131 4.3.2 DHCPREQUEST message
617 * DHCPREQUEST generated during RENEWING state:
619 * 'server identifier' MUST NOT be filled in, 'requested IP address'
620 * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
621 * client's IP address. In this situation, the client is completely
622 * configured, and is trying to extend its lease. This message will
623 * be unicast, so no relay agents will be involved in its
624 * transmission. Because 'giaddr' is therefore not filled in, the
625 * DHCP server will trust the value in 'ciaddr', and use it when
626 * replying to the client.
628 /* Fill in: op, htype, hlen, cookie, chaddr fields,
629 * random xid field (we override it below),
630 * client-id option (unless -C), message type option:
632 init_packet(&packet, DHCPREQUEST);
635 packet.ciaddr = ciaddr;
637 /* Add options: maxsize,
638 * optionally: hostname, fqdn, vendorclass,
639 * "param req" option according to -O, and options specified with -x
641 add_client_options(&packet);
643 bb_info_msg("Sending renew...");
645 return udhcp_send_kernel_packet(&packet,
647 server, SERVER_PORT);
648 return raw_bcast_from_client_config_ifindex(&packet);
651 #if ENABLE_FEATURE_UDHCPC_ARPING
652 /* Broadcast a DHCP decline message */
653 /* NOINLINE: limit stack usage in caller */
654 static NOINLINE int send_decline(uint32_t xid, uint32_t server, uint32_t requested)
656 struct dhcp_packet packet;
658 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
659 * client-id option (unless -C), message type option:
661 init_packet(&packet, DHCPDECLINE);
663 /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
664 * but in case the server is buggy and wants DHCPDECLINE's xid
665 * to match the xid which started entire handshake,
666 * we use the same xid we used in initial DHCPDISCOVER:
669 /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
670 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
672 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
674 bb_info_msg("Sending decline...");
675 return raw_bcast_from_client_config_ifindex(&packet);
679 /* Unicast a DHCP release message */
680 static int send_release(uint32_t server, uint32_t ciaddr)
682 struct dhcp_packet packet;
684 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
685 * client-id option (unless -C), message type option:
687 init_packet(&packet, DHCPRELEASE);
689 /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
690 packet.ciaddr = ciaddr;
692 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
694 bb_info_msg("Sending release...");
695 return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
698 /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
699 /* NOINLINE: limit stack usage in caller */
700 static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
703 struct ip_udp_dhcp_packet packet;
706 memset(&packet, 0, sizeof(packet));
707 bytes = safe_read(fd, &packet, sizeof(packet));
709 log1("Packet read error, ignoring");
710 /* NB: possible down interface, etc. Caller should pause. */
711 return bytes; /* returns -1 */
714 if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
715 log1("Packet is too short, ignoring");
719 if (bytes < ntohs(packet.ip.tot_len)) {
720 /* packet is bigger than sizeof(packet), we did partial read */
721 log1("Oversized packet, ignoring");
725 /* ignore any extra garbage bytes */
726 bytes = ntohs(packet.ip.tot_len);
728 /* make sure its the right packet for us, and that it passes sanity checks */
729 if (packet.ip.protocol != IPPROTO_UDP || packet.ip.version != IPVERSION
730 || packet.ip.ihl != (sizeof(packet.ip) >> 2)
731 || packet.udp.dest != htons(CLIENT_PORT)
732 /* || bytes > (int) sizeof(packet) - can't happen */
733 || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
735 log1("Unrelated/bogus packet, ignoring");
739 /* verify IP checksum */
740 check = packet.ip.check;
742 if (check != udhcp_checksum(&packet.ip, sizeof(packet.ip))) {
743 log1("Bad IP header checksum, ignoring");
747 /* verify UDP checksum. IP header has to be modified for this */
748 memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
749 /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
750 packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
751 check = packet.udp.check;
752 packet.udp.check = 0;
753 if (check && check != udhcp_checksum(&packet, bytes)) {
754 log1("Packet with bad UDP checksum received, ignoring");
758 memcpy(dhcp_pkt, &packet.data, bytes - (sizeof(packet.ip) + sizeof(packet.udp)));
760 if (dhcp_pkt->cookie != htonl(DHCP_MAGIC)) {
761 bb_info_msg("Packet with bad magic, ignoring");
764 log1("Got valid DHCP packet");
765 udhcp_dump_packet(dhcp_pkt);
766 return bytes - (sizeof(packet.ip) + sizeof(packet.udp));
772 static int sockfd = -1;
774 #define LISTEN_NONE 0
775 #define LISTEN_KERNEL 1
777 static smallint listen_mode;
779 /* initial state: (re)start DHCP negotiation */
780 #define INIT_SELECTING 0
781 /* discover was sent, DHCPOFFER reply received */
783 /* select/renew was sent, DHCPACK reply received */
785 /* half of lease passed, want to renew it by sending unicast renew requests */
787 /* renew requests were not answered, lease is almost over, send broadcast renew */
789 /* manually requested renew (SIGUSR1) */
790 #define RENEW_REQUESTED 5
791 /* release, possibly manually requested (SIGUSR2) */
793 static smallint state;
795 static int udhcp_raw_socket(int ifindex)
798 struct sockaddr_ll sock;
803 * I've selected not to see LL header, so BPF doesn't see it, too.
804 * The filter may also pass non-IP and non-ARP packets, but we do
805 * a more complete check when receiving the message in userspace.
807 * and filter shamelessly stolen from:
809 * http://www.flamewarmaster.de/software/dhcpclient/
811 * There are a few other interesting ideas on that page (look under
812 * "Motivation"). Use of netlink events is most interesting. Think
813 * of various network servers listening for events and reconfiguring.
814 * That would obsolete sending HUP signals and/or make use of restarts.
816 * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
819 * TODO: make conditional?
821 static const struct sock_filter filter_instr[] = {
822 /* load 9th byte (protocol) */
823 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
824 /* jump to L1 if it is IPPROTO_UDP, else to L4 */
825 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
826 /* L1: load halfword from offset 6 (flags and frag offset) */
827 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
828 /* jump to L4 if any bits in frag offset field are set, else to L2 */
829 BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
830 /* L2: skip IP header (load index reg with header len) */
831 BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
832 /* load udp destination port from halfword[header_len + 2] */
833 BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
834 /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
835 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
836 /* L3: accept packet */
837 BPF_STMT(BPF_RET|BPF_K, 0xffffffff),
838 /* L4: discard packet */
839 BPF_STMT(BPF_RET|BPF_K, 0),
841 static const struct sock_fprog filter_prog = {
842 .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
843 /* casting const away: */
844 .filter = (struct sock_filter *) filter_instr,
847 log1("Opening raw socket on ifindex %d", ifindex); //log2?
849 fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
850 log1("Got raw socket fd %d", fd); //log2?
852 sock.sll_family = AF_PACKET;
853 sock.sll_protocol = htons(ETH_P_IP);
854 sock.sll_ifindex = ifindex;
855 xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
857 if (CLIENT_PORT == 68) {
858 /* Use only if standard port is in use */
859 /* Ignoring error (kernel may lack support for this) */
860 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
861 sizeof(filter_prog)) >= 0)
862 log1("Attached filter to raw socket fd %d", fd); // log?
865 log1("Created raw socket");
870 static void change_listen_mode(int new_mode)
872 log1("Entering listen mode: %s",
873 new_mode != LISTEN_NONE
874 ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
878 listen_mode = new_mode;
883 if (new_mode == LISTEN_KERNEL)
884 sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
885 else if (new_mode != LISTEN_NONE)
886 sockfd = udhcp_raw_socket(client_config.ifindex);
887 /* else LISTEN_NONE: sockfd stays closed */
890 /* Called only on SIGUSR1 */
891 static void perform_renew(void)
893 bb_info_msg("Performing a DHCP renew");
896 change_listen_mode(LISTEN_KERNEL);
899 state = RENEW_REQUESTED;
901 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
902 udhcp_run_script(NULL, "deconfig");
905 change_listen_mode(LISTEN_RAW);
906 state = INIT_SELECTING;
913 static void perform_release(uint32_t requested_ip, uint32_t server_addr)
915 char buffer[sizeof("255.255.255.255")];
916 struct in_addr temp_addr;
918 /* send release packet */
919 if (state == BOUND || state == RENEWING || state == REBINDING) {
920 temp_addr.s_addr = server_addr;
921 strcpy(buffer, inet_ntoa(temp_addr));
922 temp_addr.s_addr = requested_ip;
923 bb_info_msg("Unicasting a release of %s to %s",
924 inet_ntoa(temp_addr), buffer);
925 send_release(server_addr, requested_ip); /* unicast */
926 udhcp_run_script(NULL, "deconfig");
928 bb_info_msg("Entering released state");
930 change_listen_mode(LISTEN_NONE);
934 static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
937 int len = strnlen(str, 255);
938 storage = xzalloc(len + extra + OPT_DATA);
939 storage[OPT_CODE] = code;
940 storage[OPT_LEN] = len + extra;
941 memcpy(storage + extra + OPT_DATA, str, len);
946 static void client_background(void)
949 logmode &= ~LOGMODE_STDIO;
950 /* rewrite pidfile, as our pid is different now */
951 write_pidfile(client_config.pidfile);
955 //usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
956 //usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
958 //usage:# define IF_UDHCP_VERBOSE(...)
960 //usage:#define udhcpc_trivial_usage
961 //usage: "[-fbnq"IF_UDHCP_VERBOSE("v")"oCRB] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]\n"
962 //usage: " [-H HOSTNAME] [-V VENDOR] [-x OPT:VAL]... [-O OPT]..." IF_FEATURE_UDHCP_PORT(" [-P N]")
963 //usage:#define udhcpc_full_usage "\n"
964 //usage: IF_LONG_OPTS(
965 //usage: "\n -i,--interface IFACE Interface to use (default eth0)"
966 //usage: "\n -p,--pidfile FILE Create pidfile"
967 //usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
968 //usage: "\n -B,--broadcast Request broadcast replies"
969 //usage: "\n -t,--retries N Send up to N discover packets"
970 //usage: "\n -T,--timeout N Pause between packets (default 3 seconds)"
971 //usage: "\n -A,--tryagain N Wait N seconds after failure (default 20)"
972 //usage: "\n -f,--foreground Run in foreground"
973 //usage: USE_FOR_MMU(
974 //usage: "\n -b,--background Background if lease is not obtained"
976 //usage: "\n -n,--now Exit if lease is not obtained"
977 //usage: "\n -q,--quit Exit after obtaining lease"
978 //usage: "\n -R,--release Release IP on exit"
979 //usage: "\n -S,--syslog Log to syslog too"
980 //usage: IF_FEATURE_UDHCP_PORT(
981 //usage: "\n -P,--client-port N Use port N (default 68)"
983 //usage: IF_FEATURE_UDHCPC_ARPING(
984 //usage: "\n -a,--arping Use arping to validate offered address"
986 //usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
987 //usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
988 //usage: "\n -r,--request IP Request this IP address"
989 //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
990 //usage: "\n Examples of string, numeric, and hex byte opts:"
991 //usage: "\n -x hostname:bbox - option 12"
992 //usage: "\n -x lease:3600 - option 51 (lease time)"
993 //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
994 //usage: "\n -F,--fqdn NAME Ask server to update DNS mapping for NAME"
995 //usage: "\n -H,-h,--hostname NAME Send NAME as client hostname (default none)"
996 //usage: "\n -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')"
997 //usage: "\n -C,--clientid-none Don't send MAC as client identifier"
998 //usage: IF_UDHCP_VERBOSE(
999 //usage: "\n -v Verbose"
1002 //usage: IF_NOT_LONG_OPTS(
1003 //usage: "\n -i IFACE Interface to use (default eth0)"
1004 //usage: "\n -p FILE Create pidfile"
1005 //usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
1006 //usage: "\n -B Request broadcast replies"
1007 //usage: "\n -t N Send up to N discover packets"
1008 //usage: "\n -T N Pause between packets (default 3 seconds)"
1009 //usage: "\n -A N Wait N seconds (default 20) after failure"
1010 //usage: "\n -f Run in foreground"
1011 //usage: USE_FOR_MMU(
1012 //usage: "\n -b Background if lease is not obtained"
1014 //usage: "\n -n Exit if lease is not obtained"
1015 //usage: "\n -q Exit after obtaining lease"
1016 //usage: "\n -R Release IP on exit"
1017 //usage: "\n -S Log to syslog too"
1018 //usage: IF_FEATURE_UDHCP_PORT(
1019 //usage: "\n -P N Use port N (default 68)"
1021 //usage: IF_FEATURE_UDHCPC_ARPING(
1022 //usage: "\n -a Use arping to validate offered address"
1024 //usage: "\n -O OPT Request option OPT from server (cumulative)"
1025 //usage: "\n -o Don't request any options (unless -O is given)"
1026 //usage: "\n -r IP Request this IP address"
1027 //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
1028 //usage: "\n Examples of string, numeric, and hex byte opts:"
1029 //usage: "\n -x hostname:bbox - option 12"
1030 //usage: "\n -x lease:3600 - option 51 (lease time)"
1031 //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
1032 //usage: "\n -F NAME Ask server to update DNS mapping for NAME"
1033 //usage: "\n -H,-h NAME Send NAME as client hostname (default none)"
1034 //usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
1035 //usage: "\n -C Don't send MAC as client identifier"
1036 //usage: IF_UDHCP_VERBOSE(
1037 //usage: "\n -v Verbose"
1040 //usage: "\nSignals:"
1041 //usage: "\n USR1 Renew current lease"
1042 //usage: "\n USR2 Release current lease"
1045 int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1046 int udhcpc_main(int argc UNUSED_PARAM, char **argv)
1048 uint8_t *temp, *message;
1049 const char *str_V, *str_h, *str_F, *str_r;
1050 IF_FEATURE_UDHCP_PORT(char *str_P;)
1051 void *clientid_mac_ptr;
1052 llist_t *list_O = NULL;
1053 llist_t *list_x = NULL;
1054 int tryagain_timeout = 20;
1055 int discover_timeout = 3;
1056 int discover_retries = 3;
1057 uint32_t server_addr = server_addr; /* for compiler */
1058 uint32_t requested_ip = 0;
1060 uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */
1062 int timeout; /* must be signed */
1063 unsigned already_waited_sec;
1068 struct dhcp_packet packet;
1071 /* Default options */
1072 IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
1073 IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
1074 client_config.interface = "eth0";
1075 client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
1076 str_V = "udhcp "BB_VER;
1078 /* Parse command line */
1079 /* O,x: list; -T,-t,-A take numeric param */
1080 opt_complementary = "O::x::T+:t+:A+"
1081 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
1085 IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
1086 opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:fB"
1088 IF_FEATURE_UDHCPC_ARPING("a")
1089 IF_FEATURE_UDHCP_PORT("P:")
1091 , &str_V, &str_h, &str_h, &str_F
1092 , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
1093 , &client_config.script /* s */
1094 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
1097 IF_FEATURE_UDHCP_PORT(, &str_P)
1098 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
1102 if (opt & (OPT_h|OPT_H))
1103 client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
1105 /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
1106 client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
1107 /* Flag bits: 0000NEOS
1108 * S: 1 = Client requests server to update A RR in DNS as well as PTR
1109 * O: 1 = Server indicates to client that DNS has been updated regardless
1110 * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
1111 * not "host.domain.com". Format 0 is obsolete.
1112 * N: 1 = Client requests server to not update DNS (S must be 0 then)
1113 * Two [0] bytes which follow are deprecated and must be 0.
1115 client_config.fqdn[OPT_DATA + 0] = 0x1;
1116 /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
1117 /*client_config.fqdn[OPT_DATA + 2] = 0; */
1120 requested_ip = inet_addr(str_r);
1121 #if ENABLE_FEATURE_UDHCP_PORT
1123 CLIENT_PORT = xatou16(str_P);
1124 SERVER_PORT = CLIENT_PORT - 1;
1128 client_config.no_default_options = 1;
1130 char *optstr = llist_pop(&list_O);
1131 unsigned n = bb_strtou(optstr, NULL, 0);
1132 if (errno || n > 254) {
1133 n = udhcp_option_idx(optstr);
1134 n = dhcp_optflags[n].code;
1136 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
1139 char *optstr = llist_pop(&list_x);
1140 char *colon = strchr(optstr, ':');
1143 /* now it looks similar to udhcpd's config file line:
1144 * "optname optval", using the common routine: */
1145 udhcp_str2optset(optstr, &client_config.options);
1148 if (udhcp_read_interface(client_config.interface,
1149 &client_config.ifindex,
1151 client_config.client_mac)
1156 clientid_mac_ptr = NULL;
1157 if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) {
1158 /* not suppressed and not set, set the default client ID */
1159 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
1160 client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
1161 clientid_mac_ptr = client_config.clientid + OPT_DATA+1;
1162 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1164 if (str_V[0] != '\0')
1165 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
1167 /* on NOMMU reexec (i.e., background) early */
1168 if (!(opt & OPT_f)) {
1169 bb_daemonize_or_rexec(0 /* flags */, argv);
1170 logmode = LOGMODE_NONE;
1174 openlog(applet_name, LOG_PID, LOG_DAEMON);
1175 logmode |= LOGMODE_SYSLOG;
1178 /* Make sure fd 0,1,2 are open */
1179 bb_sanitize_stdio();
1180 /* Equivalent of doing a fflush after every \n */
1182 /* Create pidfile */
1183 write_pidfile(client_config.pidfile);
1184 /* Goes to stdout (unless NOMMU) and possibly syslog */
1185 bb_info_msg("%s (v"BB_VER") started", applet_name);
1186 /* Set up the signal pipe */
1188 /* We want random_xid to be random... */
1189 srand(monotonic_us());
1191 state = INIT_SELECTING;
1192 udhcp_run_script(NULL, "deconfig");
1193 change_listen_mode(LISTEN_RAW);
1196 already_waited_sec = 0;
1198 /* Main event loop. select() waits on signal pipe and possibly
1200 * "continue" statements in code below jump to the top of the loop.
1203 /* silence "uninitialized!" warning */
1204 unsigned timestamp_before_wait = timestamp_before_wait;
1206 //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
1208 /* Was opening raw or udp socket here
1209 * if (listen_mode != LISTEN_NONE && sockfd < 0),
1210 * but on fast network renew responses return faster
1211 * than we open sockets. Thus this code is moved
1212 * to change_listen_mode(). Thus we open listen socket
1213 * BEFORE we send renew request (see "case BOUND:"). */
1215 max_fd = udhcp_sp_fd_set(&rfds, sockfd);
1217 tv.tv_sec = timeout - already_waited_sec;
1220 /* If we already timed out, fall through with retval = 0, else... */
1221 if ((int)tv.tv_sec > 0) {
1222 timestamp_before_wait = (unsigned)monotonic_sec();
1223 log1("Waiting on select...");
1224 retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
1226 /* EINTR? A signal was caught, don't panic */
1227 if (errno == EINTR) {
1228 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1231 /* Else: an error occured, panic! */
1232 bb_perror_msg_and_die("select");
1236 /* If timeout dropped to zero, time to become active:
1237 * resend discover/renew/whatever
1240 /* When running on a bridge, the ifindex may have changed
1241 * (e.g. if member interfaces were added/removed
1242 * or if the status of the bridge changed).
1243 * Refresh ifindex and client_mac:
1245 if (udhcp_read_interface(client_config.interface,
1246 &client_config.ifindex,
1248 client_config.client_mac)
1250 return 1; /* iface is gone? */
1252 if (clientid_mac_ptr)
1253 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
1255 /* We will restart the wait in any case */
1256 already_waited_sec = 0;
1259 case INIT_SELECTING:
1260 if (packet_num < discover_retries) {
1261 if (packet_num == 0)
1264 send_discover(xid, requested_ip);
1265 timeout = discover_timeout;
1270 udhcp_run_script(NULL, "leasefail");
1271 #if BB_MMU /* -b is not supported on NOMMU */
1272 if (opt & OPT_b) { /* background if no lease */
1273 bb_info_msg("No lease, forking to background");
1274 client_background();
1275 /* do not background again! */
1276 opt = ((opt & ~OPT_b) | OPT_f);
1279 if (opt & OPT_n) { /* abort if no lease */
1280 bb_info_msg("No lease, failing");
1284 /* wait before trying again */
1285 timeout = tryagain_timeout;
1289 if (packet_num < discover_retries) {
1290 /* send broadcast select packet */
1291 send_select(xid, server_addr, requested_ip);
1292 timeout = discover_timeout;
1296 /* Timed out, go back to init state.
1297 * "discover...select...discover..." loops
1298 * were seen in the wild. Treat them similarly
1299 * to "no response to discover" case */
1300 change_listen_mode(LISTEN_RAW);
1301 state = INIT_SELECTING;
1304 /* 1/2 lease passed, enter renewing state */
1306 client_config.first_secs = 0; /* make secs field count from 0 */
1307 change_listen_mode(LISTEN_KERNEL);
1308 log1("Entering renew state");
1309 /* fall right through */
1310 case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
1311 case_RENEW_REQUESTED:
1314 /* send an unicast renew request */
1315 /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1316 * a new UDP socket for sending inside send_renew.
1317 * I hazard to guess existing listening socket
1318 * is somehow conflicting with it, but why is it
1319 * not deterministic then?! Strange.
1320 * Anyway, it does recover by eventually failing through
1321 * into INIT_SELECTING state.
1323 send_renew(xid, server_addr, requested_ip);
1327 /* Timed out, enter rebinding state */
1328 log1("Entering rebinding state");
1330 /* fall right through */
1332 /* Switch to bcast receive */
1333 change_listen_mode(LISTEN_RAW);
1334 /* Lease is *really* about to run out,
1335 * try to find DHCP server using broadcast */
1337 /* send a broadcast renew request */
1338 send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
1342 /* Timed out, enter init state */
1343 bb_info_msg("Lease lost, entering init state");
1344 udhcp_run_script(NULL, "deconfig");
1345 state = INIT_SELECTING;
1346 client_config.first_secs = 0; /* make secs field count from 0 */
1347 /*timeout = 0; - already is */
1350 /* case RELEASED: */
1352 /* yah, I know, *you* say it would never happen */
1354 continue; /* back to main loop */
1355 } /* if select timed out */
1357 /* select() didn't timeout, something happened */
1359 /* Is it a signal? */
1360 /* note: udhcp_sp_read checks FD_ISSET before reading */
1361 switch (udhcp_sp_read(&rfds)) {
1363 client_config.first_secs = 0; /* make secs field count from 0 */
1365 if (state == RENEW_REQUESTED)
1366 goto case_RENEW_REQUESTED;
1367 /* Start things over */
1369 /* Kill any timeouts, user wants this to hurry along */
1373 perform_release(requested_ip, server_addr);
1377 bb_info_msg("Received SIGTERM");
1378 if (opt & OPT_R) /* release on quit */
1379 perform_release(requested_ip, server_addr);
1383 /* Is it a packet? */
1384 if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
1390 /* A packet is ready, read it */
1391 if (listen_mode == LISTEN_KERNEL)
1392 len = udhcp_recv_kernel_packet(&packet, sockfd);
1394 len = udhcp_recv_raw_packet(&packet, sockfd);
1396 /* Error is severe, reopen socket */
1397 bb_info_msg("Read error: %s, reopening socket", strerror(errno));
1398 sleep(discover_timeout); /* 3 seconds by default */
1399 change_listen_mode(listen_mode); /* just close and reopen */
1401 /* If this packet will turn out to be unrelated/bogus,
1402 * we will go back and wait for next one.
1403 * Be sure timeout is properly decreased. */
1404 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1409 if (packet.xid != xid) {
1410 log1("xid %x (our is %x), ignoring packet",
1411 (unsigned)packet.xid, (unsigned)xid);
1415 /* Ignore packets that aren't for us */
1416 if (packet.hlen != 6
1417 || memcmp(packet.chaddr, client_config.client_mac, 6) != 0
1419 //FIXME: need to also check that last 10 bytes are zero
1420 log1("chaddr does not match, ignoring packet"); // log2?
1424 message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
1425 if (message == NULL) {
1426 bb_error_msg("no message type option, ignoring packet");
1431 case INIT_SELECTING:
1432 /* Must be a DHCPOFFER to one of our xid's */
1433 if (*message == DHCPOFFER) {
1434 /* TODO: why we don't just fetch server's IP from IP header? */
1435 temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
1437 bb_error_msg("no server ID, ignoring packet");
1439 /* still selecting - this server looks bad */
1441 /* it IS unaligned sometimes, don't "optimize" */
1442 move_from_unaligned32(server_addr, temp);
1443 /*xid = packet.xid; - already is */
1444 requested_ip = packet.yiaddr;
1446 /* enter requesting state */
1450 already_waited_sec = 0;
1455 case RENEW_REQUESTED:
1457 if (*message == DHCPACK) {
1458 temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
1460 bb_error_msg("no lease time with ACK, using 1 hour lease");
1461 lease_seconds = 60 * 60;
1463 /* it IS unaligned sometimes, don't "optimize" */
1464 move_from_unaligned32(lease_seconds, temp);
1465 lease_seconds = ntohl(lease_seconds);
1466 lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
1467 if (lease_seconds < 10) /* and not too small */
1470 #if ENABLE_FEATURE_UDHCPC_ARPING
1472 /* RFC 2131 3.1 paragraph 5:
1473 * "The client receives the DHCPACK message with configuration
1474 * parameters. The client SHOULD perform a final check on the
1475 * parameters (e.g., ARP for allocated network address), and notes
1476 * the duration of the lease specified in the DHCPACK message. At this
1477 * point, the client is configured. If the client detects that the
1478 * address is already in use (e.g., through the use of ARP),
1479 * the client MUST send a DHCPDECLINE message to the server and restarts
1480 * the configuration process..." */
1481 if (!arpping(packet.yiaddr,
1484 client_config.client_mac,
1485 client_config.interface)
1487 bb_info_msg("Offered address is in use "
1488 "(got ARP reply), declining");
1489 send_decline(xid, server_addr, packet.yiaddr);
1491 if (state != REQUESTING)
1492 udhcp_run_script(NULL, "deconfig");
1493 change_listen_mode(LISTEN_RAW);
1494 state = INIT_SELECTING;
1495 client_config.first_secs = 0; /* make secs field count from 0 */
1497 timeout = tryagain_timeout;
1499 already_waited_sec = 0;
1500 continue; /* back to main loop */
1504 /* enter bound state */
1505 timeout = lease_seconds / 2;
1507 struct in_addr temp_addr;
1508 temp_addr.s_addr = packet.yiaddr;
1509 bb_info_msg("Lease of %s obtained, lease time %u",
1510 inet_ntoa(temp_addr), (unsigned)lease_seconds);
1512 requested_ip = packet.yiaddr;
1513 udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
1516 change_listen_mode(LISTEN_NONE);
1517 if (opt & OPT_q) { /* quit after lease */
1518 if (opt & OPT_R) /* release on quit */
1519 perform_release(requested_ip, server_addr);
1522 /* future renew failures should not exit (JM) */
1524 #if BB_MMU /* NOMMU case backgrounded earlier */
1525 if (!(opt & OPT_f)) {
1526 client_background();
1527 /* do not background again! */
1528 opt = ((opt & ~OPT_b) | OPT_f);
1531 already_waited_sec = 0;
1532 continue; /* back to main loop */
1534 if (*message == DHCPNAK) {
1535 /* return to init state */
1536 bb_info_msg("Received DHCP NAK");
1537 udhcp_run_script(&packet, "nak");
1538 if (state != REQUESTING)
1539 udhcp_run_script(NULL, "deconfig");
1540 change_listen_mode(LISTEN_RAW);
1541 sleep(3); /* avoid excessive network traffic */
1542 state = INIT_SELECTING;
1543 client_config.first_secs = 0; /* make secs field count from 0 */
1547 already_waited_sec = 0;
1550 /* case BOUND: - ignore all packets */
1551 /* case RELEASED: - ignore all packets */
1553 /* back to main loop */
1554 } /* for (;;) - main loop ends */
1559 /*if (client_config.pidfile) - remove_pidfile has its own check */
1560 remove_pidfile(client_config.pidfile);