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 <netpacket/packet.h>
31 # include <net/ethernet.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 /*** Script execution code ***/
43 /* get a rough idea of how long an option will be (rounding up...) */
44 static const uint8_t len_of_option_as_string[] = {
45 [OPTION_IP] = sizeof("255.255.255.255 "),
46 [OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2,
47 [OPTION_STATIC_ROUTES]= sizeof("255.255.255.255/32 255.255.255.255 "),
49 #if ENABLE_FEATURE_UDHCP_RFC3397
52 // [OPTION_BOOLEAN] = sizeof("yes "),
53 [OPTION_U8] = sizeof("255 "),
54 [OPTION_U16] = sizeof("65535 "),
55 // [OPTION_S16] = sizeof("-32768 "),
56 [OPTION_U32] = sizeof("4294967295 "),
57 [OPTION_S32] = sizeof("-2147483684 "),
60 /* note: ip is a pointer to an IP in network order, possibly misaliged */
61 static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
63 return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
66 /* really simple implementation, just count the bits */
67 static int mton(uint32_t mask)
70 mask = ntohl(mask); /* 111110000-like bit pattern */
78 /* Create "opt_name=opt_value" string */
79 static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_option *type_p, const char *opt_name)
81 unsigned upper_length;
82 int len, type, optlen;
88 /* option points to OPT_DATA, need to go back and get OPT_LEN */
89 len = option[OPT_LEN - OPT_DATA];
90 type = type_p->flags & OPTION_TYPE_MASK;
91 optlen = dhcp_option_lengths[type];
92 upper_length = len_of_option_as_string[type] * (len / optlen);
94 dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
95 dest += sprintf(ret, "%s=", opt_name);
97 while (len >= optlen) {
100 dest += sprint_nip(dest, "", option);
105 dest += sprint_nip(dest, "", option);
106 // TODO: it can be a list only if (type_p->flags & OPTION_LIST).
107 // Should we bail out/warn if we see multi-ip option which is
108 // not allowed to be such? For example, DHCP_BROADCAST...
110 // case OPTION_BOOLEAN:
111 // dest += sprintf(dest, *option ? "yes" : "no");
114 dest += sprintf(dest, "%u", *option);
117 move_from_unaligned16(val_u16, option);
118 dest += sprintf(dest, "%u", ntohs(val_u16));
120 // case OPTION_S16: {
122 // move_from_unaligned16(val_s16, option);
123 // dest += sprintf(dest, "%d", ntohs(val_s16));
127 move_from_unaligned32(val_u32, option);
128 dest += sprintf(dest, "%lu", (unsigned long) ntohl(val_u32));
131 move_from_unaligned32(val_s32, option);
132 dest += sprintf(dest, "%ld", (long) ntohl(val_s32));
135 memcpy(dest, option, len);
137 return ret; /* Short circuit this case */
138 case OPTION_STATIC_ROUTES: {
139 /* Option binary format:
140 * mask [one byte, 0..32]
141 * ip [big endian, 0..4 bytes depending on mask]
142 * router [big endian, 4 bytes]
145 * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
147 const char *pfx = "";
149 while (len >= 1 + 4) { /* mask + 0-byte ip + router */
162 bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
163 while (--bytes >= 0) {
171 dest += sprint_nip(dest, pfx, (void*) &nip);
173 dest += sprintf(dest, "/%u ", mask);
175 dest += sprint_nip(dest, "", option);
182 #if ENABLE_FEATURE_UDHCP_RFC3397
184 /* unpack option into dest; use ret for prefix (i.e., "optname=") */
185 dest = dname_dec(option, len, ret);
190 /* error. return "optname=" string */
204 /* put all the parameters into the environment */
205 static char **fill_envp(struct dhcp_packet *packet)
210 const char *opt_name;
215 for (i = 0; dhcp_options[i].code; i++) {
216 if (udhcp_get_option(packet, dhcp_options[i].code)) {
218 if (dhcp_options[i].code == DHCP_SUBNET)
219 num_options++; /* for mton */
222 if (packet->siaddr_nip)
224 temp = udhcp_get_option(packet, DHCP_OPTION_OVERLOAD);
227 if (!(over & FILE_FIELD) && packet->file[0])
229 if (!(over & SNAME_FIELD) && packet->sname[0])
233 curr = envp = xzalloc(sizeof(char *) * (num_options + 3));
234 *curr = xasprintf("interface=%s", client_config.interface);
240 *curr = xmalloc(sizeof("ip=255.255.255.255"));
241 sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
244 opt_name = dhcp_option_strings;
247 temp = udhcp_get_option(packet, dhcp_options[i].code);
250 *curr = xmalloc_optname_optval(temp, &dhcp_options[i], opt_name);
253 /* Fill in a subnet bits option for things like /24 */
254 if (dhcp_options[i].code == DHCP_SUBNET) {
256 move_from_unaligned32(subnet, temp);
257 *curr = xasprintf("mask=%d", mton(subnet));
261 opt_name += strlen(opt_name) + 1;
264 if (packet->siaddr_nip) {
265 *curr = xmalloc(sizeof("siaddr=255.255.255.255"));
266 sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
269 if (!(over & FILE_FIELD) && packet->file[0]) {
270 /* watch out for invalid packets */
271 *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
274 if (!(over & SNAME_FIELD) && packet->sname[0]) {
275 /* watch out for invalid packets */
276 *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
282 /* Call a script with a par file and env vars */
283 static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
288 if (client_config.script == NULL)
291 envp = fill_envp(packet);
294 log1("Executing %s %s", client_config.script, name);
295 argv[0] = (char*) client_config.script;
296 argv[1] = (char*) name;
298 spawn_and_wait(argv);
300 for (curr = envp; *curr; curr++) {
309 /*** Sending/receiving packets ***/
311 static ALWAYS_INLINE uint32_t random_xid(void)
316 /* Initialize the packet with the proper defaults */
317 static void init_packet(struct dhcp_packet *packet, char type)
319 udhcp_init_header(packet, type);
320 memcpy(packet->chaddr, client_config.client_mac, 6);
321 if (client_config.clientid)
322 udhcp_add_binary_option(packet, client_config.clientid);
323 if (client_config.hostname)
324 udhcp_add_binary_option(packet, client_config.hostname);
325 if (client_config.fqdn)
326 udhcp_add_binary_option(packet, client_config.fqdn);
327 if (type != DHCPDECLINE
328 && type != DHCPRELEASE
329 && client_config.vendorclass
331 udhcp_add_binary_option(packet, client_config.vendorclass);
335 static void add_client_options(struct dhcp_packet *packet)
337 /* Add a "param req" option with the list of options we'd like to have
338 * from stubborn DHCP servers. Pull the data from the struct in common.c.
339 * No bounds checking because it goes towards the head of the packet. */
341 int end = udhcp_end_option(packet->options);
344 for (i = 0; (c = dhcp_options[i].code) != 0; i++) {
345 if (( (dhcp_options[i].flags & OPTION_REQ)
346 && !client_config.no_default_options
348 || (client_config.opt_mask[c >> 3] & (1 << (c & 7)))
350 packet->options[end + OPT_DATA + len] = c;
355 packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
356 packet->options[end + OPT_LEN] = len;
357 packet->options[end + OPT_DATA + len] = DHCP_END;
360 /* Add -x options if any */
362 struct option_set *curr = client_config.options;
364 udhcp_add_binary_option(packet, curr->data);
367 // if (client_config.sname)
368 // strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
369 // if (client_config.boot_file)
370 // strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
375 * 4.4.4 Use of broadcast and unicast
377 * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
378 * messages, unless the client knows the address of a DHCP server.
379 * The client unicasts DHCPRELEASE messages to the server. Because
380 * the client is declining the use of the IP address supplied by the server,
381 * the client broadcasts DHCPDECLINE messages.
383 * When the DHCP client knows the address of a DHCP server, in either
384 * INIT or REBOOTING state, the client may use that address
385 * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
386 * The client may also use unicast to send DHCPINFORM messages
387 * to a known DHCP server. If the client receives no response to DHCP
388 * messages sent to the IP address of a known DHCP server, the DHCP
389 * client reverts to using the IP broadcast address.
392 static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet)
394 return udhcp_send_raw_packet(packet,
395 /*src*/ INADDR_ANY, CLIENT_PORT,
396 /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
397 client_config.ifindex);
400 /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
401 static int send_discover(uint32_t xid, uint32_t requested)
403 struct dhcp_packet packet;
405 init_packet(&packet, DHCPDISCOVER);
408 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
409 /* Explicitly saying that we want RFC-compliant packets helps
410 * some buggy DHCP servers to NOT send bigger packets */
411 udhcp_add_simple_option(&packet, DHCP_MAX_SIZE, htons(576));
412 add_client_options(&packet);
414 bb_info_msg("Sending discover...");
415 return raw_bcast_from_client_config_ifindex(&packet);
418 /* Broadcast a DHCP request message */
419 /* RFC 2131 3.1 paragraph 3:
420 * "The client _broadcasts_ a DHCPREQUEST message..."
422 static int send_select(uint32_t xid, uint32_t server, uint32_t requested)
424 struct dhcp_packet packet;
427 init_packet(&packet, DHCPREQUEST);
429 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
430 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
431 add_client_options(&packet);
433 addr.s_addr = requested;
434 bb_info_msg("Sending select for %s...", inet_ntoa(addr));
435 return raw_bcast_from_client_config_ifindex(&packet);
438 /* Unicast or broadcast a DHCP renew message */
439 static int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
441 struct dhcp_packet packet;
443 init_packet(&packet, DHCPREQUEST);
445 packet.ciaddr = ciaddr;
446 add_client_options(&packet);
448 bb_info_msg("Sending renew...");
450 return udhcp_send_kernel_packet(&packet,
452 server, SERVER_PORT);
453 return raw_bcast_from_client_config_ifindex(&packet);
456 #if ENABLE_FEATURE_UDHCPC_ARPING
457 /* Broadcast a DHCP decline message */
458 static int send_decline(uint32_t xid, uint32_t server, uint32_t requested)
460 struct dhcp_packet packet;
462 init_packet(&packet, DHCPDECLINE);
464 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
465 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
467 bb_info_msg("Sending decline...");
468 return raw_bcast_from_client_config_ifindex(&packet);
472 /* Unicast a DHCP release message */
473 static int send_release(uint32_t server, uint32_t ciaddr)
475 struct dhcp_packet packet;
477 init_packet(&packet, DHCPRELEASE);
478 packet.xid = random_xid();
479 packet.ciaddr = ciaddr;
481 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
483 bb_info_msg("Sending release...");
484 return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
487 /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
488 static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
491 struct ip_udp_dhcp_packet packet;
494 memset(&packet, 0, sizeof(packet));
495 bytes = safe_read(fd, &packet, sizeof(packet));
497 log1("Packet read error, ignoring");
498 /* NB: possible down interface, etc. Caller should pause. */
499 return bytes; /* returns -1 */
502 if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
503 log1("Packet is too short, ignoring");
507 if (bytes < ntohs(packet.ip.tot_len)) {
508 /* packet is bigger than sizeof(packet), we did partial read */
509 log1("Oversized packet, ignoring");
513 /* ignore any extra garbage bytes */
514 bytes = ntohs(packet.ip.tot_len);
516 /* make sure its the right packet for us, and that it passes sanity checks */
517 if (packet.ip.protocol != IPPROTO_UDP || packet.ip.version != IPVERSION
518 || packet.ip.ihl != (sizeof(packet.ip) >> 2)
519 || packet.udp.dest != htons(CLIENT_PORT)
520 /* || bytes > (int) sizeof(packet) - can't happen */
521 || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
523 log1("Unrelated/bogus packet, ignoring");
527 /* verify IP checksum */
528 check = packet.ip.check;
530 if (check != udhcp_checksum(&packet.ip, sizeof(packet.ip))) {
531 log1("Bad IP header checksum, ignoring");
535 /* verify UDP checksum. IP header has to be modified for this */
536 memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
537 /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
538 packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
539 check = packet.udp.check;
540 packet.udp.check = 0;
541 if (check && check != udhcp_checksum(&packet, bytes)) {
542 log1("Packet with bad UDP checksum received, ignoring");
546 memcpy(dhcp_pkt, &packet.data, bytes - (sizeof(packet.ip) + sizeof(packet.udp)));
548 if (dhcp_pkt->cookie != htonl(DHCP_MAGIC)) {
549 bb_info_msg("Packet with bad magic, ignoring");
552 log1("Got valid DHCP packet");
553 udhcp_dump_packet(dhcp_pkt);
554 return bytes - (sizeof(packet.ip) + sizeof(packet.udp));
560 static int sockfd = -1;
562 #define LISTEN_NONE 0
563 #define LISTEN_KERNEL 1
565 static smallint listen_mode;
567 /* initial state: (re)start DHCP negotiation */
568 #define INIT_SELECTING 0
569 /* discover was sent, DHCPOFFER reply received */
571 /* select/renew was sent, DHCPACK reply received */
573 /* half of lease passed, want to renew it by sending unicast renew requests */
575 /* renew requests were not answered, lease is almost over, send broadcast renew */
577 /* manually requested renew (SIGUSR1) */
578 #define RENEW_REQUESTED 5
579 /* release, possibly manually requested (SIGUSR2) */
581 static smallint state;
583 static int udhcp_raw_socket(int ifindex)
586 struct sockaddr_ll sock;
591 * I've selected not to see LL header, so BPF doesn't see it, too.
592 * The filter may also pass non-IP and non-ARP packets, but we do
593 * a more complete check when receiving the message in userspace.
595 * and filter shamelessly stolen from:
597 * http://www.flamewarmaster.de/software/dhcpclient/
599 * There are a few other interesting ideas on that page (look under
600 * "Motivation"). Use of netlink events is most interesting. Think
601 * of various network servers listening for events and reconfiguring.
602 * That would obsolete sending HUP signals and/or make use of restarts.
604 * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
607 * TODO: make conditional?
609 #define SERVER_AND_CLIENT_PORTS ((67 << 16) + 68)
610 static const struct sock_filter filter_instr[] = {
612 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
613 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 2, 0), /* L5, L1, is UDP? */
614 /* ugly check for arp on ethernet-like and IPv4 */
615 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2), /* L1: */
616 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 0x08000604, 3, 4), /* L3, L4 */
618 BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0), /* L5: */
619 /* check udp source and destination ports */
620 BPF_STMT(BPF_LD|BPF_W|BPF_IND, 0),
621 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, SERVER_AND_CLIENT_PORTS, 0, 1), /* L3, L4 */
623 BPF_STMT(BPF_RET|BPF_K, 0x0fffffff ), /* L3: pass */
624 BPF_STMT(BPF_RET|BPF_K, 0), /* L4: reject */
626 static const struct sock_fprog filter_prog = {
627 .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
628 /* casting const away: */
629 .filter = (struct sock_filter *) filter_instr,
632 log1("Opening raw socket on ifindex %d", ifindex); //log2?
634 fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
635 log1("Got raw socket fd %d", fd); //log2?
637 if (SERVER_PORT == 67 && CLIENT_PORT == 68) {
638 /* Use only if standard ports are in use */
639 /* Ignoring error (kernel may lack support for this) */
640 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
641 sizeof(filter_prog)) >= 0)
642 log1("Attached filter to raw socket fd %d", fd); // log?
645 sock.sll_family = AF_PACKET;
646 sock.sll_protocol = htons(ETH_P_IP);
647 sock.sll_ifindex = ifindex;
648 xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
649 log1("Created raw socket");
654 static void change_listen_mode(int new_mode)
656 log1("Entering listen mode: %s",
657 new_mode != LISTEN_NONE
658 ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
662 listen_mode = new_mode;
667 if (new_mode == LISTEN_KERNEL)
668 sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
669 else if (new_mode != LISTEN_NONE)
670 sockfd = udhcp_raw_socket(client_config.ifindex);
671 /* else LISTEN_NONE: sockfd stays closed */
674 static void perform_renew(void)
676 bb_info_msg("Performing a DHCP renew");
679 change_listen_mode(LISTEN_KERNEL);
682 state = RENEW_REQUESTED;
684 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
685 udhcp_run_script(NULL, "deconfig");
688 change_listen_mode(LISTEN_RAW);
689 state = INIT_SELECTING;
696 static void perform_release(uint32_t requested_ip, uint32_t server_addr)
698 char buffer[sizeof("255.255.255.255")];
699 struct in_addr temp_addr;
701 /* send release packet */
702 if (state == BOUND || state == RENEWING || state == REBINDING) {
703 temp_addr.s_addr = server_addr;
704 strcpy(buffer, inet_ntoa(temp_addr));
705 temp_addr.s_addr = requested_ip;
706 bb_info_msg("Unicasting a release of %s to %s",
707 inet_ntoa(temp_addr), buffer);
708 send_release(server_addr, requested_ip); /* unicast */
709 udhcp_run_script(NULL, "deconfig");
711 bb_info_msg("Entering released state");
713 change_listen_mode(LISTEN_NONE);
717 static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
720 int len = strnlen(str, 255);
721 storage = xzalloc(len + extra + OPT_DATA);
722 storage[OPT_CODE] = code;
723 storage[OPT_LEN] = len + extra;
724 memcpy(storage + extra + OPT_DATA, str, len);
729 static void client_background(void)
732 logmode &= ~LOGMODE_STDIO;
733 /* rewrite pidfile, as our pid is different now */
734 write_pidfile(client_config.pidfile);
738 int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
739 int udhcpc_main(int argc UNUSED_PARAM, char **argv)
741 uint8_t *temp, *message;
742 const char *str_c, *str_V, *str_h, *str_F, *str_r;
743 IF_FEATURE_UDHCP_PORT(char *str_P;)
744 llist_t *list_O = NULL;
745 llist_t *list_x = NULL;
746 int tryagain_timeout = 20;
747 int discover_timeout = 3;
748 int discover_retries = 3;
749 uint32_t server_addr = server_addr; /* for compiler */
750 uint32_t requested_ip = 0;
752 uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */
754 int timeout; /* must be signed */
755 unsigned already_waited_sec;
760 struct dhcp_packet packet;
764 static const char udhcpc_longopts[] ALIGN1 =
765 "clientid\0" Required_argument "c"
766 "clientid-none\0" No_argument "C"
767 "vendorclass\0" Required_argument "V"
768 "hostname\0" Required_argument "H"
769 "fqdn\0" Required_argument "F"
770 "interface\0" Required_argument "i"
771 "now\0" No_argument "n"
772 "pidfile\0" Required_argument "p"
773 "quit\0" No_argument "q"
774 "release\0" No_argument "R"
775 "request\0" Required_argument "r"
776 "script\0" Required_argument "s"
777 "timeout\0" Required_argument "T"
778 "version\0" No_argument "v"
779 "retries\0" Required_argument "t"
780 "tryagain\0" Required_argument "A"
781 "syslog\0" No_argument "S"
782 "request-option\0" Required_argument "O"
783 "no-default-options\0" No_argument "o"
784 "foreground\0" No_argument "f"
785 "background\0" No_argument "b"
786 IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
787 IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
812 /* The rest has variable bit positions, need to be clever */
814 USE_FOR_MMU( OPTBIT_b,)
815 IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
816 IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
817 USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
818 IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
819 IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
822 /* Default options. */
823 IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
824 IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
825 client_config.interface = "eth0";
826 client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
827 str_V = "udhcp "BB_VER;
829 /* Parse command line */
830 /* Cc: mutually exclusive; O,x: list; -T,-t,-A take numeric param */
831 opt_complementary = "c--C:C--c:O::x::T+:t+:A+"
832 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
836 IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
837 opt = getopt32(argv, "c:CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:f"
839 IF_FEATURE_UDHCPC_ARPING("a")
840 IF_FEATURE_UDHCP_PORT("P:")
842 , &str_c, &str_V, &str_h, &str_h, &str_F
843 , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
844 , &client_config.script /* s */
845 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
848 IF_FEATURE_UDHCP_PORT(, &str_P)
849 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
853 if (opt & (OPT_h|OPT_H))
854 client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
856 /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
857 client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
858 /* Flag bits: 0000NEOS
859 * S: 1 = Client requests server to update A RR in DNS as well as PTR
860 * O: 1 = Server indicates to client that DNS has been updated regardless
861 * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
862 * not "host.domain.com". Format 0 is obsolete.
863 * N: 1 = Client requests server to not update DNS (S must be 0 then)
864 * Two [0] bytes which follow are deprecated and must be 0.
866 client_config.fqdn[OPT_DATA + 0] = 0x1;
867 /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
868 /*client_config.fqdn[OPT_DATA + 2] = 0; */
871 requested_ip = inet_addr(str_r);
872 #if ENABLE_FEATURE_UDHCP_PORT
874 CLIENT_PORT = xatou16(str_P);
875 SERVER_PORT = CLIENT_PORT - 1;
879 client_config.no_default_options = 1;
881 char *optstr = llist_pop(&list_O);
882 int n = index_in_strings(dhcp_option_strings, optstr);
884 bb_error_msg_and_die("unknown option '%s'", optstr);
885 n = dhcp_options[n].code;
886 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
890 char *optstr = llist_pop(&list_x);
891 char *colon = strchr(optstr, ':');
894 n = index_in_strings(dhcp_option_strings, optstr);
896 bb_error_msg_and_die("unknown option '%s'", optstr);
899 udhcp_str2optset(optstr, &client_config.options);
902 if (udhcp_read_interface(client_config.interface,
903 &client_config.ifindex,
905 client_config.client_mac)
911 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
912 } else if (!(opt & OPT_C)) {
913 /* not set and not suppressed, set the default client ID */
914 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
915 client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
916 memcpy(client_config.clientid + OPT_DATA+1, client_config.client_mac, 6);
918 if (str_V[0] != '\0')
919 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
921 /* on NOMMU reexec (i.e., background) early */
922 if (!(opt & OPT_f)) {
923 bb_daemonize_or_rexec(0 /* flags */, argv);
924 logmode = LOGMODE_NONE;
928 openlog(applet_name, LOG_PID, LOG_DAEMON);
929 logmode |= LOGMODE_SYSLOG;
932 /* Make sure fd 0,1,2 are open */
934 /* Equivalent of doing a fflush after every \n */
937 write_pidfile(client_config.pidfile);
938 /* Goes to stdout (unless NOMMU) and possibly syslog */
939 bb_info_msg("%s (v"BB_VER") started", applet_name);
940 /* Set up the signal pipe */
942 /* We want random_xid to be random... */
943 srand(monotonic_us());
945 state = INIT_SELECTING;
946 udhcp_run_script(NULL, "deconfig");
947 change_listen_mode(LISTEN_RAW);
950 already_waited_sec = 0;
952 /* Main event loop. select() waits on signal pipe and possibly
954 * "continue" statements in code below jump to the top of the loop.
957 /* silence "uninitialized!" warning */
958 unsigned timestamp_before_wait = timestamp_before_wait;
960 //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
962 /* Was opening raw or udp socket here
963 * if (listen_mode != LISTEN_NONE && sockfd < 0),
964 * but on fast network renew responses return faster
965 * than we open sockets. Thus this code is moved
966 * to change_listen_mode(). Thus we open listen socket
967 * BEFORE we send renew request (see "case BOUND:"). */
969 max_fd = udhcp_sp_fd_set(&rfds, sockfd);
971 tv.tv_sec = timeout - already_waited_sec;
974 /* If we already timed out, fall through with retval = 0, else... */
975 if ((int)tv.tv_sec > 0) {
976 timestamp_before_wait = (unsigned)monotonic_sec();
977 log1("Waiting on select...");
978 retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
980 /* EINTR? A signal was caught, don't panic */
981 if (errno == EINTR) {
982 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
985 /* Else: an error occured, panic! */
986 bb_perror_msg_and_die("select");
990 /* If timeout dropped to zero, time to become active:
991 * resend discover/renew/whatever
994 /* We will restart the wait in any case */
995 already_waited_sec = 0;
999 if (packet_num < discover_retries) {
1000 if (packet_num == 0)
1003 send_discover(xid, requested_ip);
1004 timeout = discover_timeout;
1009 udhcp_run_script(NULL, "leasefail");
1010 #if BB_MMU /* -b is not supported on NOMMU */
1011 if (opt & OPT_b) { /* background if no lease */
1012 bb_info_msg("No lease, forking to background");
1013 client_background();
1014 /* do not background again! */
1015 opt = ((opt & ~OPT_b) | OPT_f);
1018 if (opt & OPT_n) { /* abort if no lease */
1019 bb_info_msg("No lease, failing");
1023 /* wait before trying again */
1024 timeout = tryagain_timeout;
1028 if (packet_num < discover_retries) {
1029 /* send broadcast select packet */
1030 send_select(xid, server_addr, requested_ip);
1031 timeout = discover_timeout;
1035 /* Timed out, go back to init state.
1036 * "discover...select...discover..." loops
1037 * were seen in the wild. Treat them similarly
1038 * to "no response to discover" case */
1039 change_listen_mode(LISTEN_RAW);
1040 state = INIT_SELECTING;
1043 /* 1/2 lease passed, enter renewing state */
1045 change_listen_mode(LISTEN_KERNEL);
1046 log1("Entering renew state");
1047 /* fall right through */
1048 case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
1049 case_RENEW_REQUESTED:
1052 /* send an unicast renew request */
1053 /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1054 * a new UDP socket for sending inside send_renew.
1055 * I hazard to guess existing listening socket
1056 * is somehow conflicting with it, but why is it
1057 * not deterministic then?! Strange.
1058 * Anyway, it does recover by eventually failing through
1059 * into INIT_SELECTING state.
1061 send_renew(xid, server_addr, requested_ip);
1065 /* Timed out, enter rebinding state */
1066 log1("Entering rebinding state");
1068 /* fall right through */
1070 /* Switch to bcast receive */
1071 change_listen_mode(LISTEN_RAW);
1072 /* Lease is *really* about to run out,
1073 * try to find DHCP server using broadcast */
1075 /* send a broadcast renew request */
1076 send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
1080 /* Timed out, enter init state */
1081 bb_info_msg("Lease lost, entering init state");
1082 udhcp_run_script(NULL, "deconfig");
1083 state = INIT_SELECTING;
1084 /*timeout = 0; - already is */
1087 /* case RELEASED: */
1089 /* yah, I know, *you* say it would never happen */
1091 continue; /* back to main loop */
1092 } /* if select timed out */
1094 /* select() didn't timeout, something happened */
1096 /* Is it a signal? */
1097 /* note: udhcp_sp_read checks FD_ISSET before reading */
1098 switch (udhcp_sp_read(&rfds)) {
1101 if (state == RENEW_REQUESTED)
1102 goto case_RENEW_REQUESTED;
1103 /* Start things over */
1105 /* Kill any timeouts, user wants this to hurry along */
1109 perform_release(requested_ip, server_addr);
1113 bb_info_msg("Received SIGTERM");
1114 if (opt & OPT_R) /* release on quit */
1115 perform_release(requested_ip, server_addr);
1119 /* Is it a packet? */
1120 if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
1126 /* A packet is ready, read it */
1127 if (listen_mode == LISTEN_KERNEL)
1128 len = udhcp_recv_kernel_packet(&packet, sockfd);
1130 len = udhcp_recv_raw_packet(&packet, sockfd);
1132 /* Error is severe, reopen socket */
1133 bb_info_msg("Read error: %s, reopening socket", strerror(errno));
1134 sleep(discover_timeout); /* 3 seconds by default */
1135 change_listen_mode(listen_mode); /* just close and reopen */
1137 /* If this packet will turn out to be unrelated/bogus,
1138 * we will go back and wait for next one.
1139 * Be sure timeout is properly decreased. */
1140 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
1145 if (packet.xid != xid) {
1146 log1("xid %x (our is %x), ignoring packet",
1147 (unsigned)packet.xid, (unsigned)xid);
1151 /* Ignore packets that aren't for us */
1152 if (packet.hlen != 6
1153 || memcmp(packet.chaddr, client_config.client_mac, 6)
1155 //FIXME: need to also check that last 10 bytes are zero
1156 log1("chaddr does not match, ignoring packet"); // log2?
1160 message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
1161 if (message == NULL) {
1162 bb_error_msg("no message type option, ignoring packet");
1167 case INIT_SELECTING:
1168 /* Must be a DHCPOFFER to one of our xid's */
1169 if (*message == DHCPOFFER) {
1170 /* TODO: why we don't just fetch server's IP from IP header? */
1171 temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
1173 bb_error_msg("no server ID in message");
1175 /* still selecting - this server looks bad */
1177 /* it IS unaligned sometimes, don't "optimize" */
1178 move_from_unaligned32(server_addr, temp);
1180 requested_ip = packet.yiaddr;
1182 /* enter requesting state */
1186 already_waited_sec = 0;
1191 case RENEW_REQUESTED:
1193 if (*message == DHCPACK) {
1194 temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
1196 bb_error_msg("no lease time with ACK, using 1 hour lease");
1197 lease_seconds = 60 * 60;
1199 /* it IS unaligned sometimes, don't "optimize" */
1200 move_from_unaligned32(lease_seconds, temp);
1201 lease_seconds = ntohl(lease_seconds);
1202 lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
1203 if (lease_seconds < 10) /* and not too small */
1206 #if ENABLE_FEATURE_UDHCPC_ARPING
1208 /* RFC 2131 3.1 paragraph 5:
1209 * "The client receives the DHCPACK message with configuration
1210 * parameters. The client SHOULD perform a final check on the
1211 * parameters (e.g., ARP for allocated network address), and notes
1212 * the duration of the lease specified in the DHCPACK message. At this
1213 * point, the client is configured. If the client detects that the
1214 * address is already in use (e.g., through the use of ARP),
1215 * the client MUST send a DHCPDECLINE message to the server and restarts
1216 * the configuration process..." */
1217 if (!arpping(packet.yiaddr,
1220 client_config.client_mac,
1221 client_config.interface)
1223 bb_info_msg("Offered address is in use "
1224 "(got ARP reply), declining");
1225 send_decline(xid, server_addr, packet.yiaddr);
1227 if (state != REQUESTING)
1228 udhcp_run_script(NULL, "deconfig");
1229 change_listen_mode(LISTEN_RAW);
1230 state = INIT_SELECTING;
1232 timeout = tryagain_timeout;
1234 already_waited_sec = 0;
1235 continue; /* back to main loop */
1239 /* enter bound state */
1240 timeout = lease_seconds / 2;
1242 struct in_addr temp_addr;
1243 temp_addr.s_addr = packet.yiaddr;
1244 bb_info_msg("Lease of %s obtained, lease time %u",
1245 inet_ntoa(temp_addr), (unsigned)lease_seconds);
1247 requested_ip = packet.yiaddr;
1248 udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
1251 change_listen_mode(LISTEN_NONE);
1252 if (opt & OPT_q) { /* quit after lease */
1253 if (opt & OPT_R) /* release on quit */
1254 perform_release(requested_ip, server_addr);
1257 /* future renew failures should not exit (JM) */
1259 #if BB_MMU /* NOMMU case backgrounded earlier */
1260 if (!(opt & OPT_f)) {
1261 client_background();
1262 /* do not background again! */
1263 opt = ((opt & ~OPT_b) | OPT_f);
1266 already_waited_sec = 0;
1267 continue; /* back to main loop */
1269 if (*message == DHCPNAK) {
1270 /* return to init state */
1271 bb_info_msg("Received DHCP NAK");
1272 udhcp_run_script(&packet, "nak");
1273 if (state != REQUESTING)
1274 udhcp_run_script(NULL, "deconfig");
1275 change_listen_mode(LISTEN_RAW);
1276 sleep(3); /* avoid excessive network traffic */
1277 state = INIT_SELECTING;
1281 already_waited_sec = 0;
1284 /* case BOUND: - ignore all packets */
1285 /* case RELEASED: - ignore all packets */
1287 /* back to main loop */
1288 } /* for (;;) - main loop ends */
1293 /*if (client_config.pidfile) - remove_pidfile has its own check */
1294 remove_pidfile(client_config.pidfile);