/* vi: set sw=4 ts=4: */
-/* dhcpc.c
- *
- * udhcp DHCP client
+/*
+ * udhcp client
*
* Russ Dill <Russ.Dill@asu.edu> July 2001
*
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
-
-#include <getopt.h>
-
+#include <syslog.h>
+/* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
+#define WANT_PIDFILE 1
#include "common.h"
#include "dhcpd.h"
#include "dhcpc.h"
-#include "options.h"
+#include <asm/types.h>
+#if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined(_NEWLIB_VERSION)
+# include <netpacket/packet.h>
+# include <net/ethernet.h>
+#else
+# include <linux/if_packet.h>
+# include <linux/if_ether.h>
+#endif
+#include <linux/filter.h>
+
+/* struct client_config_t client_config is in bb_common_bufsiz1 */
+
+
+/*** Script execution code ***/
+
+/* get a rough idea of how long an option will be (rounding up...) */
+static const uint8_t len_of_option_as_string[] = {
+ [OPTION_IP ] = sizeof("255.255.255.255 "),
+ [OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2,
+ [OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "),
+ [OPTION_STRING ] = 1,
+#if ENABLE_FEATURE_UDHCP_RFC3397
+ [OPTION_DNS_STRING ] = 1, /* unused */
+ /* Hmmm, this severely overestimates size if SIP_SERVERS option
+ * is in domain name form: N-byte option in binary form
+ * mallocs ~16*N bytes. But it is freed almost at once.
+ */
+ [OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "),
+#endif
+// [OPTION_BOOLEAN ] = sizeof("yes "),
+ [OPTION_U8 ] = sizeof("255 "),
+ [OPTION_U16 ] = sizeof("65535 "),
+// [OPTION_S16 ] = sizeof("-32768 "),
+ [OPTION_U32 ] = sizeof("4294967295 "),
+ [OPTION_S32 ] = sizeof("-2147483684 "),
+};
+
+/* note: ip is a pointer to an IP in network order, possibly misaliged */
+static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
+{
+ return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
+}
+
+/* really simple implementation, just count the bits */
+static int mton(uint32_t mask)
+{
+ int i = 0;
+ mask = ntohl(mask); /* 111110000-like bit pattern */
+ while (mask) {
+ i++;
+ mask <<= 1;
+ }
+ return i;
+}
-static int state;
-/* Something is definitely wrong here. IPv4 addresses
- * in variables of type long?? BTW, we use inet_ntoa()
- * in the code. Manpage says that struct in_addr has a member of type long (!)
- * which holds IPv4 address, and the struct is passed by value (!!)
+/* Create "opt_name=opt_value" string */
+static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name)
+{
+ unsigned upper_length;
+ int len, type, optlen;
+ char *dest, *ret;
+
+ /* option points to OPT_DATA, need to go back and get OPT_LEN */
+ len = option[OPT_LEN - OPT_DATA];
+
+ type = optflag->flags & OPTION_TYPE_MASK;
+ optlen = dhcp_option_lengths[type];
+ upper_length = len_of_option_as_string[type] * ((unsigned)len / (unsigned)optlen);
+
+ dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
+ dest += sprintf(ret, "%s=", opt_name);
+
+ while (len >= optlen) {
+ unsigned ip_ofs = 0;
+
+ switch (type) {
+ case OPTION_IP_PAIR:
+ dest += sprint_nip(dest, "", option);
+ *dest++ = '/';
+ ip_ofs = 4;
+ /* fall through */
+ case OPTION_IP:
+ dest += sprint_nip(dest, "", option + ip_ofs);
+ break;
+// case OPTION_BOOLEAN:
+// dest += sprintf(dest, *option ? "yes" : "no");
+// break;
+ case OPTION_U8:
+ dest += sprintf(dest, "%u", *option);
+ break;
+// case OPTION_S16:
+ case OPTION_U16: {
+ uint16_t val_u16;
+ move_from_unaligned16(val_u16, option);
+ dest += sprintf(dest, "%u", ntohs(val_u16));
+ break;
+ }
+ case OPTION_S32:
+ case OPTION_U32: {
+ uint32_t val_u32;
+ move_from_unaligned32(val_u32, option);
+ dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
+ break;
+ }
+ case OPTION_STRING:
+ memcpy(dest, option, len);
+ dest[len] = '\0';
+ return ret; /* Short circuit this case */
+ case OPTION_STATIC_ROUTES: {
+ /* Option binary format:
+ * mask [one byte, 0..32]
+ * ip [big endian, 0..4 bytes depending on mask]
+ * router [big endian, 4 bytes]
+ * may be repeated
+ *
+ * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
+ */
+ const char *pfx = "";
+
+ while (len >= 1 + 4) { /* mask + 0-byte ip + router */
+ uint32_t nip;
+ uint8_t *p;
+ unsigned mask;
+ int bytes;
+
+ mask = *option++;
+ if (mask > 32)
+ break;
+ len--;
+
+ nip = 0;
+ p = (void*) &nip;
+ bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
+ while (--bytes >= 0) {
+ *p++ = *option++;
+ len--;
+ }
+ if (len < 4)
+ break;
+
+ /* print ip/mask */
+ dest += sprint_nip(dest, pfx, (void*) &nip);
+ pfx = " ";
+ dest += sprintf(dest, "/%u ", mask);
+ /* print router */
+ dest += sprint_nip(dest, "", option);
+ option += 4;
+ len -= 4;
+ }
+
+ return ret;
+ }
+#if ENABLE_FEATURE_UDHCP_RFC3397
+ case OPTION_DNS_STRING:
+ /* unpack option into dest; use ret for prefix (i.e., "optname=") */
+ dest = dname_dec(option, len, ret);
+ if (dest) {
+ free(ret);
+ return dest;
+ }
+ /* error. return "optname=" string */
+ return ret;
+ case OPTION_SIP_SERVERS:
+ /* Option binary format:
+ * type: byte
+ * type=0: domain names, dns-compressed
+ * type=1: IP addrs
+ */
+ option++;
+ len--;
+ if (option[-1] == 0) {
+ dest = dname_dec(option, len, ret);
+ if (dest) {
+ free(ret);
+ return dest;
+ }
+ } else
+ if (option[-1] == 1) {
+ const char *pfx = "";
+ while (1) {
+ len -= 4;
+ if (len < 0)
+ break;
+ dest += sprint_nip(dest, pfx, option);
+ pfx = " ";
+ option += 4;
+ }
+ }
+ return ret;
+#endif
+ } /* switch */
+ option += optlen;
+ len -= optlen;
+// TODO: it can be a list only if (optflag->flags & OPTION_LIST).
+// Should we bail out/warn if we see multi-ip option which is
+// not allowed to be such (for example, DHCP_BROADCAST)? -
+ if (len <= 0 /* || !(optflag->flags & OPTION_LIST) */)
+ break;
+ *dest++ = ' ';
+ *dest = '\0';
+ }
+ return ret;
+}
+
+/* put all the parameters into the environment */
+static char **fill_envp(struct dhcp_packet *packet)
+{
+ int envc;
+ int i;
+ char **envp, **curr;
+ const char *opt_name;
+ uint8_t *temp;
+ uint8_t overload = 0;
+
+ /* We need 6 elements for:
+ * "interface=IFACE"
+ * "ip=N.N.N.N" from packet->yiaddr
+ * "siaddr=IP" from packet->siaddr_nip (unless 0)
+ * "boot_file=FILE" from packet->file (unless overloaded)
+ * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded)
+ * terminating NULL
+ */
+ envc = 6;
+ /* +1 element for each option, +2 for subnet option: */
+ if (packet) {
+ for (i = 0; dhcp_optflags[i].code; i++) {
+ if (udhcp_get_option(packet, dhcp_optflags[i].code)) {
+ if (dhcp_optflags[i].code == DHCP_SUBNET)
+ envc++; /* for mton */
+ envc++;
+ }
+ }
+ temp = udhcp_get_option(packet, DHCP_OPTION_OVERLOAD);
+ if (temp)
+ overload = *temp;
+ }
+ curr = envp = xzalloc(sizeof(char *) * envc);
+
+ *curr = xasprintf("interface=%s", client_config.interface);
+ putenv(*curr++);
+
+ if (!packet)
+ return envp;
+
+ *curr = xmalloc(sizeof("ip=255.255.255.255"));
+ sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
+ putenv(*curr++);
+
+ opt_name = dhcp_option_strings;
+ i = 0;
+ while (*opt_name) {
+ temp = udhcp_get_option(packet, dhcp_optflags[i].code);
+ if (!temp)
+ goto next;
+ *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name);
+ putenv(*curr++);
+ if (dhcp_optflags[i].code == DHCP_SUBNET) {
+ /* Subnet option: make things like "$ip/$mask" possible */
+ uint32_t subnet;
+ move_from_unaligned32(subnet, temp);
+ *curr = xasprintf("mask=%d", mton(subnet));
+ putenv(*curr++);
+ }
+ next:
+ opt_name += strlen(opt_name) + 1;
+ i++;
+ }
+ if (packet->siaddr_nip) {
+ *curr = xmalloc(sizeof("siaddr=255.255.255.255"));
+ sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
+ putenv(*curr++);
+ }
+ if (!(overload & FILE_FIELD) && packet->file[0]) {
+ /* watch out for invalid packets */
+ *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
+ putenv(*curr++);
+ }
+ if (!(overload & SNAME_FIELD) && packet->sname[0]) {
+ /* watch out for invalid packets */
+ *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
+ putenv(*curr++);
+ }
+ return envp;
+}
+
+/* Call a script with a par file and env vars */
+static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
+{
+ char **envp, **curr;
+ char *argv[3];
+
+ if (client_config.script == NULL)
+ return;
+
+ envp = fill_envp(packet);
+
+ /* call script */
+ log1("Executing %s %s", client_config.script, name);
+ argv[0] = (char*) client_config.script;
+ argv[1] = (char*) name;
+ argv[2] = NULL;
+ spawn_and_wait(argv);
+
+ for (curr = envp; *curr; curr++) {
+ log2(" %s", *curr);
+ bb_unsetenv_and_free(*curr);
+ }
+ free(envp);
+}
+
+
+/*** Sending/receiving packets ***/
+
+static ALWAYS_INLINE uint32_t random_xid(void)
+{
+ return rand();
+}
+
+/* Initialize the packet with the proper defaults */
+static void init_packet(struct dhcp_packet *packet, char type)
+{
+ /* Fill in: op, htype, hlen, cookie fields; message type option: */
+ udhcp_init_header(packet, type);
+
+ packet->xid = random_xid();
+
+ memcpy(packet->chaddr, client_config.client_mac, 6);
+ if (client_config.clientid)
+ udhcp_add_binary_option(packet, client_config.clientid);
+}
+
+static void add_client_options(struct dhcp_packet *packet)
+{
+ uint8_t c;
+ int i, end, len;
+
+ udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
+ if (client_config.hostname)
+ udhcp_add_binary_option(packet, client_config.hostname);
+ if (client_config.fqdn)
+ udhcp_add_binary_option(packet, client_config.fqdn);
+ if (client_config.vendorclass)
+ udhcp_add_binary_option(packet, client_config.vendorclass);
+
+ /* Add a "param req" option with the list of options we'd like to have
+ * from stubborn DHCP servers. Pull the data from the struct in common.c.
+ * No bounds checking because it goes towards the head of the packet. */
+ end = udhcp_end_option(packet->options);
+ len = 0;
+ for (i = 0; (c = dhcp_optflags[i].code) != 0; i++) {
+ if (( (dhcp_optflags[i].flags & OPTION_REQ)
+ && !client_config.no_default_options
+ )
+ || (client_config.opt_mask[c >> 3] & (1 << (c & 7)))
+ ) {
+ packet->options[end + OPT_DATA + len] = c;
+ len++;
+ }
+ }
+ if (len) {
+ packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
+ packet->options[end + OPT_LEN] = len;
+ packet->options[end + OPT_DATA + len] = DHCP_END;
+ }
+
+ /* Add -x options if any */
+ {
+ struct option_set *curr = client_config.options;
+ while (curr) {
+ udhcp_add_binary_option(packet, curr->data);
+ curr = curr->next;
+ }
+// if (client_config.sname)
+// strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
+// if (client_config.boot_file)
+// strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
+ }
+}
+
+/* RFC 2131
+ * 4.4.4 Use of broadcast and unicast
+ *
+ * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
+ * messages, unless the client knows the address of a DHCP server.
+ * The client unicasts DHCPRELEASE messages to the server. Because
+ * the client is declining the use of the IP address supplied by the server,
+ * the client broadcasts DHCPDECLINE messages.
+ *
+ * When the DHCP client knows the address of a DHCP server, in either
+ * INIT or REBOOTING state, the client may use that address
+ * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
+ * The client may also use unicast to send DHCPINFORM messages
+ * to a known DHCP server. If the client receives no response to DHCP
+ * messages sent to the IP address of a known DHCP server, the DHCP
+ * client reverts to using the IP broadcast address.
+ */
+
+static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet)
+{
+ return udhcp_send_raw_packet(packet,
+ /*src*/ INADDR_ANY, CLIENT_PORT,
+ /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
+ client_config.ifindex);
+}
+
+/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
+static int send_discover(uint32_t xid, uint32_t requested)
+{
+ struct dhcp_packet packet;
+
+ /* Fill in: op, htype, hlen, cookie, chaddr fields,
+ * random xid field (we override it below),
+ * client-id option (unless -C), message type option:
+ */
+ init_packet(&packet, DHCPDISCOVER);
+
+ packet.xid = xid;
+ if (requested)
+ udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
+
+ /* Add options: maxsize,
+ * optionally: hostname, fqdn, vendorclass,
+ * "param req" option according to -O, options specified with -x
+ */
+ add_client_options(&packet);
+
+ bb_info_msg("Sending discover...");
+ return raw_bcast_from_client_config_ifindex(&packet);
+}
+
+/* Broadcast a DHCP request message */
+/* RFC 2131 3.1 paragraph 3:
+ * "The client _broadcasts_ a DHCPREQUEST message..."
+ */
+static int send_select(uint32_t xid, uint32_t server, uint32_t requested)
+{
+ struct dhcp_packet packet;
+ struct in_addr addr;
+
+/*
+ * RFC 2131 4.3.2 DHCPREQUEST message
+ * ...
+ * If the DHCPREQUEST message contains a 'server identifier'
+ * option, the message is in response to a DHCPOFFER message.
+ * Otherwise, the message is a request to verify or extend an
+ * existing lease. If the client uses a 'client identifier'
+ * in a DHCPREQUEST message, it MUST use that same 'client identifier'
+ * in all subsequent messages. If the client included a list
+ * of requested parameters in a DHCPDISCOVER message, it MUST
+ * include that list in all subsequent messages.
*/
-static unsigned long requested_ip; /* = 0 */
-static uint32_t server_addr;
-static unsigned long timeout;
-static int packet_num; /* = 0 */
-static int fd = -1;
+ /* Fill in: op, htype, hlen, cookie, chaddr fields,
+ * random xid field (we override it below),
+ * client-id option (unless -C), message type option:
+ */
+ init_packet(&packet, DHCPREQUEST);
+
+ packet.xid = xid;
+ udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
+
+ udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
+
+ /* Add options: maxsize,
+ * optionally: hostname, fqdn, vendorclass,
+ * "param req" option according to -O, and options specified with -x
+ */
+ add_client_options(&packet);
+
+ addr.s_addr = requested;
+ bb_info_msg("Sending select for %s...", inet_ntoa(addr));
+ return raw_bcast_from_client_config_ifindex(&packet);
+}
+
+/* Unicast or broadcast a DHCP renew message */
+static int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
+{
+ struct dhcp_packet packet;
+
+/*
+ * RFC 2131 4.3.2 DHCPREQUEST message
+ * ...
+ * DHCPREQUEST generated during RENEWING state:
+ *
+ * 'server identifier' MUST NOT be filled in, 'requested IP address'
+ * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
+ * client's IP address. In this situation, the client is completely
+ * configured, and is trying to extend its lease. This message will
+ * be unicast, so no relay agents will be involved in its
+ * transmission. Because 'giaddr' is therefore not filled in, the
+ * DHCP server will trust the value in 'ciaddr', and use it when
+ * replying to the client.
+ */
+ /* Fill in: op, htype, hlen, cookie, chaddr fields,
+ * random xid field (we override it below),
+ * client-id option (unless -C), message type option:
+ */
+ init_packet(&packet, DHCPREQUEST);
+
+ packet.xid = xid;
+ packet.ciaddr = ciaddr;
+
+ /* Add options: maxsize,
+ * optionally: hostname, fqdn, vendorclass,
+ * "param req" option according to -O, and options specified with -x
+ */
+ add_client_options(&packet);
+
+ bb_info_msg("Sending renew...");
+ if (server)
+ return udhcp_send_kernel_packet(&packet,
+ ciaddr, CLIENT_PORT,
+ server, SERVER_PORT);
+ return raw_bcast_from_client_config_ifindex(&packet);
+}
+
+#if ENABLE_FEATURE_UDHCPC_ARPING
+/* Broadcast a DHCP decline message */
+static int send_decline(uint32_t xid, uint32_t server, uint32_t requested)
+{
+ struct dhcp_packet packet;
+
+ /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
+ * client-id option (unless -C), message type option:
+ */
+ init_packet(&packet, DHCPDECLINE);
+
+ /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
+ * but in case the server is buggy and wants DHCPDECLINE's xid
+ * to match the xid which started entire handshake,
+ * we use the same xid we used in initial DHCPDISCOVER:
+ */
+ packet.xid = xid;
+ /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
+ udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
+
+ udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
+
+ bb_info_msg("Sending decline...");
+ return raw_bcast_from_client_config_ifindex(&packet);
+}
+#endif
+
+/* Unicast a DHCP release message */
+static int send_release(uint32_t server, uint32_t ciaddr)
+{
+ struct dhcp_packet packet;
+
+ /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
+ * client-id option (unless -C), message type option:
+ */
+ init_packet(&packet, DHCPRELEASE);
+
+ /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
+ packet.ciaddr = ciaddr;
+
+ udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
+
+ bb_info_msg("Sending release...");
+ return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
+}
+
+/* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
+static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
+{
+ int bytes;
+ struct ip_udp_dhcp_packet packet;
+ uint16_t check;
+
+ memset(&packet, 0, sizeof(packet));
+ bytes = safe_read(fd, &packet, sizeof(packet));
+ if (bytes < 0) {
+ log1("Packet read error, ignoring");
+ /* NB: possible down interface, etc. Caller should pause. */
+ return bytes; /* returns -1 */
+ }
-#define LISTEN_NONE 0
+ if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
+ log1("Packet is too short, ignoring");
+ return -2;
+ }
+
+ if (bytes < ntohs(packet.ip.tot_len)) {
+ /* packet is bigger than sizeof(packet), we did partial read */
+ log1("Oversized packet, ignoring");
+ return -2;
+ }
+
+ /* ignore any extra garbage bytes */
+ bytes = ntohs(packet.ip.tot_len);
+
+ /* make sure its the right packet for us, and that it passes sanity checks */
+ if (packet.ip.protocol != IPPROTO_UDP || packet.ip.version != IPVERSION
+ || packet.ip.ihl != (sizeof(packet.ip) >> 2)
+ || packet.udp.dest != htons(CLIENT_PORT)
+ /* || bytes > (int) sizeof(packet) - can't happen */
+ || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
+ ) {
+ log1("Unrelated/bogus packet, ignoring");
+ return -2;
+ }
+
+ /* verify IP checksum */
+ check = packet.ip.check;
+ packet.ip.check = 0;
+ if (check != udhcp_checksum(&packet.ip, sizeof(packet.ip))) {
+ log1("Bad IP header checksum, ignoring");
+ return -2;
+ }
+
+ /* verify UDP checksum. IP header has to be modified for this */
+ memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
+ /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
+ packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
+ check = packet.udp.check;
+ packet.udp.check = 0;
+ if (check && check != udhcp_checksum(&packet, bytes)) {
+ log1("Packet with bad UDP checksum received, ignoring");
+ return -2;
+ }
+
+ memcpy(dhcp_pkt, &packet.data, bytes - (sizeof(packet.ip) + sizeof(packet.udp)));
+
+ if (dhcp_pkt->cookie != htonl(DHCP_MAGIC)) {
+ bb_info_msg("Packet with bad magic, ignoring");
+ return -2;
+ }
+ log1("Got valid DHCP packet");
+ udhcp_dump_packet(dhcp_pkt);
+ return bytes - (sizeof(packet.ip) + sizeof(packet.udp));
+}
+
+
+/*** Main ***/
+
+static int sockfd = -1;
+
+#define LISTEN_NONE 0
#define LISTEN_KERNEL 1
-#define LISTEN_RAW 2
-static int listen_mode;
+#define LISTEN_RAW 2
+static smallint listen_mode;
+
+/* initial state: (re)start DHCP negotiation */
+#define INIT_SELECTING 0
+/* discover was sent, DHCPOFFER reply received */
+#define REQUESTING 1
+/* select/renew was sent, DHCPACK reply received */
+#define BOUND 2
+/* half of lease passed, want to renew it by sending unicast renew requests */
+#define RENEWING 3
+/* renew requests were not answered, lease is almost over, send broadcast renew */
+#define REBINDING 4
+/* manually requested renew (SIGUSR1) */
+#define RENEW_REQUESTED 5
+/* release, possibly manually requested (SIGUSR2) */
+#define RELEASED 6
+static smallint state;
-struct client_config_t client_config;
+static int udhcp_raw_socket(int ifindex)
+{
+ int fd;
+ struct sockaddr_ll sock;
+ /*
+ * Comment:
+ *
+ * I've selected not to see LL header, so BPF doesn't see it, too.
+ * The filter may also pass non-IP and non-ARP packets, but we do
+ * a more complete check when receiving the message in userspace.
+ *
+ * and filter shamelessly stolen from:
+ *
+ * http://www.flamewarmaster.de/software/dhcpclient/
+ *
+ * There are a few other interesting ideas on that page (look under
+ * "Motivation"). Use of netlink events is most interesting. Think
+ * of various network servers listening for events and reconfiguring.
+ * That would obsolete sending HUP signals and/or make use of restarts.
+ *
+ * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
+ * License: GPL v2.
+ *
+ * TODO: make conditional?
+ */
+#define SERVER_AND_CLIENT_PORTS ((67 << 16) + 68)
+ static const struct sock_filter filter_instr[] = {
+ /* check for udp */
+ BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 2, 0), /* L5, L1, is UDP? */
+ /* ugly check for arp on ethernet-like and IPv4 */
+ BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2), /* L1: */
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 0x08000604, 3, 4), /* L3, L4 */
+ /* skip IP header */
+ BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0), /* L5: */
+ /* check udp source and destination ports */
+ BPF_STMT(BPF_LD|BPF_W|BPF_IND, 0),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, SERVER_AND_CLIENT_PORTS, 0, 1), /* L3, L4 */
+ /* returns */
+ BPF_STMT(BPF_RET|BPF_K, 0x0fffffff ), /* L3: pass */
+ BPF_STMT(BPF_RET|BPF_K, 0), /* L4: reject */
+ };
+ static const struct sock_fprog filter_prog = {
+ .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
+ /* casting const away: */
+ .filter = (struct sock_filter *) filter_instr,
+ };
+
+ log1("Opening raw socket on ifindex %d", ifindex); //log2?
+
+ fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
+ log1("Got raw socket fd %d", fd); //log2?
+
+ if (SERVER_PORT == 67 && CLIENT_PORT == 68) {
+ /* Use only if standard ports are in use */
+ /* Ignoring error (kernel may lack support for this) */
+ if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
+ sizeof(filter_prog)) >= 0)
+ log1("Attached filter to raw socket fd %d", fd); // log?
+ }
-/* just a little helper */
-static void change_mode(int new_mode)
+ sock.sll_family = AF_PACKET;
+ sock.sll_protocol = htons(ETH_P_IP);
+ sock.sll_ifindex = ifindex;
+ xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
+ log1("Created raw socket");
+
+ return fd;
+}
+
+static void change_listen_mode(int new_mode)
{
- DEBUG("entering %s listen mode",
- new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
- if (fd >= 0) close(fd);
- fd = -1;
+ log1("Entering listen mode: %s",
+ new_mode != LISTEN_NONE
+ ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
+ : "none"
+ );
+
listen_mode = new_mode;
+ if (sockfd >= 0) {
+ close(sockfd);
+ sockfd = -1;
+ }
+ if (new_mode == LISTEN_KERNEL)
+ sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
+ else if (new_mode != LISTEN_NONE)
+ sockfd = udhcp_raw_socket(client_config.ifindex);
+ /* else LISTEN_NONE: sockfd stays closed */
}
-
-/* perform a renew */
static void perform_renew(void)
{
bb_info_msg("Performing a DHCP renew");
switch (state) {
case BOUND:
- change_mode(LISTEN_KERNEL);
+ change_listen_mode(LISTEN_KERNEL);
case RENEWING:
case REBINDING:
state = RENEW_REQUESTED;
udhcp_run_script(NULL, "deconfig");
case REQUESTING:
case RELEASED:
- change_mode(LISTEN_RAW);
+ change_listen_mode(LISTEN_RAW);
state = INIT_SELECTING;
break;
case INIT_SELECTING:
break;
}
-
- /* start things over */
- packet_num = 0;
-
- /* Kill any timeouts because the user wants this to hurry along */
- timeout = 0;
}
-
-/* perform a release */
-static void perform_release(void)
+static void perform_release(uint32_t requested_ip, uint32_t server_addr)
{
- char buffer[16];
+ char buffer[sizeof("255.255.255.255")];
struct in_addr temp_addr;
/* send release packet */
if (state == BOUND || state == RENEWING || state == REBINDING) {
temp_addr.s_addr = server_addr;
- sprintf(buffer, "%s", inet_ntoa(temp_addr));
+ strcpy(buffer, inet_ntoa(temp_addr));
temp_addr.s_addr = requested_ip;
bb_info_msg("Unicasting a release of %s to %s",
inet_ntoa(temp_addr), buffer);
}
bb_info_msg("Entering released state");
- change_mode(LISTEN_NONE);
+ change_listen_mode(LISTEN_NONE);
state = RELEASED;
- timeout = 0x7fffffff;
}
-
-static void client_background(void)
-{
- udhcp_background(client_config.pidfile);
- client_config.foreground = 1; /* Do not fork again. */
- client_config.background_if_no_lease = 0;
-}
-
-
static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
{
uint8_t *storage;
- int len = strlen(str);
- if (len > 255) len = 255;
+ int len = strnlen(str, 255);
storage = xzalloc(len + extra + OPT_DATA);
storage[OPT_CODE] = code;
storage[OPT_LEN] = len + extra;
return storage;
}
+#if BB_MMU
+static void client_background(void)
+{
+ bb_daemonize(0);
+ logmode &= ~LOGMODE_STDIO;
+ /* rewrite pidfile, as our pid is different now */
+ write_pidfile(client_config.pidfile);
+}
+#endif
-int udhcpc_main(int argc, char *argv[])
+//usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
+//usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
+//usage:#else
+//usage:# define IF_UDHCP_VERBOSE(...)
+//usage:#endif
+//usage:#define udhcpc_trivial_usage
+//usage: "[-fbnq"IF_UDHCP_VERBOSE("v")"oCR] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]\n"
+//usage: " [-H HOSTNAME] [-V VENDOR] [-x OPT:VAL]... [-O OPT]..." IF_FEATURE_UDHCP_PORT(" [-P N]")
+//usage:#define udhcpc_full_usage "\n"
+//usage: IF_LONG_OPTS(
+//usage: "\n -i,--interface IFACE Interface to use (default eth0)"
+//usage: "\n -p,--pidfile FILE Create pidfile"
+//usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
+//usage: "\n -t,--retries N Send up to N discover packets"
+//usage: "\n -T,--timeout N Pause between packets (default 3 seconds)"
+//usage: "\n -A,--tryagain N Wait N seconds after failure (default 20)"
+//usage: "\n -f,--foreground Run in foreground"
+//usage: USE_FOR_MMU(
+//usage: "\n -b,--background Background if lease is not obtained"
+//usage: )
+//usage: "\n -n,--now Exit if lease is not obtained"
+//usage: "\n -q,--quit Exit after obtaining lease"
+//usage: "\n -R,--release Release IP on exit"
+//usage: "\n -S,--syslog Log to syslog too"
+//usage: IF_FEATURE_UDHCP_PORT(
+//usage: "\n -P,--client-port N Use port N (default 68)"
+//usage: )
+//usage: IF_FEATURE_UDHCPC_ARPING(
+//usage: "\n -a,--arping Use arping to validate offered address"
+//usage: )
+//usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
+//usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
+//usage: "\n -r,--request IP Request this IP address"
+//usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
+//usage: "\n Examples of string, numeric, and hex byte opts:"
+//usage: "\n -x hostname:bbox - option 12"
+//usage: "\n -x lease:3600 - option 51 (lease time)"
+//usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
+//usage: "\n -F,--fqdn NAME Ask server to update DNS mapping for NAME"
+//usage: "\n -H,-h,--hostname NAME Send NAME as client hostname (default none)"
+//usage: "\n -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')"
+//usage: "\n -C,--clientid-none Don't send MAC as client identifier"
+//usage: IF_UDHCP_VERBOSE(
+//usage: "\n -v Verbose"
+//usage: )
+//usage: )
+//usage: IF_NOT_LONG_OPTS(
+//usage: "\n -i IFACE Interface to use (default eth0)"
+//usage: "\n -p FILE Create pidfile"
+//usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
+//usage: "\n -t N Send up to N discover packets"
+//usage: "\n -T N Pause between packets (default 3 seconds)"
+//usage: "\n -A N Wait N seconds (default 20) after failure"
+//usage: "\n -f Run in foreground"
+//usage: USE_FOR_MMU(
+//usage: "\n -b Background if lease is not obtained"
+//usage: )
+//usage: "\n -n Exit if lease is not obtained"
+//usage: "\n -q Exit after obtaining lease"
+//usage: "\n -R Release IP on exit"
+//usage: "\n -S Log to syslog too"
+//usage: IF_FEATURE_UDHCP_PORT(
+//usage: "\n -P N Use port N (default 68)"
+//usage: )
+//usage: IF_FEATURE_UDHCPC_ARPING(
+//usage: "\n -a Use arping to validate offered address"
+//usage: )
+//usage: "\n -O OPT Request option OPT from server (cumulative)"
+//usage: "\n -o Don't request any options (unless -O is given)"
+//usage: "\n -r IP Request this IP address"
+//usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
+//usage: "\n Examples of string, numeric, and hex byte opts:"
+//usage: "\n -x hostname:bbox - option 12"
+//usage: "\n -x lease:3600 - option 51 (lease time)"
+//usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
+//usage: "\n -F NAME Ask server to update DNS mapping for NAME"
+//usage: "\n -H,-h NAME Send NAME as client hostname (default none)"
+//usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
+//usage: "\n -C Don't send MAC as client identifier"
+//usage: IF_UDHCP_VERBOSE(
+//usage: "\n -v Verbose"
+//usage: )
+//usage: )
+
+int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int udhcpc_main(int argc UNUSED_PARAM, char **argv)
{
uint8_t *temp, *message;
- char *str_c, *str_V, *str_h, *str_F, *str_r, *str_T, *str_t;
- unsigned long t1 = 0, t2 = 0, xid = 0;
- unsigned long start = 0, lease = 0;
- long now;
+ const char *str_V, *str_h, *str_F, *str_r;
+ IF_FEATURE_UDHCP_PORT(char *str_P;)
+ llist_t *list_O = NULL;
+ llist_t *list_x = NULL;
+ int tryagain_timeout = 20;
+ int discover_timeout = 3;
+ int discover_retries = 3;
+ uint32_t server_addr = server_addr; /* for compiler */
+ uint32_t requested_ip = 0;
+ uint32_t xid = 0;
+ uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */
+ int packet_num;
+ int timeout; /* must be signed */
+ unsigned already_waited_sec;
unsigned opt;
int max_fd;
- int sig;
int retval;
- int len;
- int no_clientid = 0;
- fd_set rfds;
struct timeval tv;
- struct dhcpMessage packet;
- struct in_addr temp_addr;
+ struct dhcp_packet packet;
+ fd_set rfds;
+#if ENABLE_LONG_OPTS
+ static const char udhcpc_longopts[] ALIGN1 =
+ "clientid-none\0" No_argument "C"
+ "vendorclass\0" Required_argument "V"
+ "hostname\0" Required_argument "H"
+ "fqdn\0" Required_argument "F"
+ "interface\0" Required_argument "i"
+ "now\0" No_argument "n"
+ "pidfile\0" Required_argument "p"
+ "quit\0" No_argument "q"
+ "release\0" No_argument "R"
+ "request\0" Required_argument "r"
+ "script\0" Required_argument "s"
+ "timeout\0" Required_argument "T"
+ "version\0" No_argument "v"
+ "retries\0" Required_argument "t"
+ "tryagain\0" Required_argument "A"
+ "syslog\0" No_argument "S"
+ "request-option\0" Required_argument "O"
+ "no-default-options\0" No_argument "o"
+ "foreground\0" No_argument "f"
+ "background\0" No_argument "b"
+ IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
+ IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
+ ;
+#endif
enum {
- OPT_c = 1 << 0,
- OPT_C = 1 << 1,
- OPT_V = 1 << 2,
- OPT_f = 1 << 3,
- OPT_b = 1 << 4,
- OPT_H = 1 << 5,
- OPT_h = 1 << 6,
- OPT_F = 1 << 7,
- OPT_i = 1 << 8,
- OPT_n = 1 << 9,
- OPT_p = 1 << 10,
- OPT_q = 1 << 11,
- OPT_R = 1 << 12,
- OPT_r = 1 << 13,
- OPT_s = 1 << 14,
- OPT_T = 1 << 15,
- OPT_t = 1 << 16,
- OPT_v = 1 << 17,
- };
-#if ENABLE_GETOPT_LONG
- static const struct option arg_options[] = {
- { "clientid", required_argument, 0, 'c' },
- { "clientid-none", no_argument, 0, 'C' },
- { "vendorclass", required_argument, 0, 'V' },
- { "foreground", no_argument, 0, 'f' },
- { "background", no_argument, 0, 'b' },
- { "hostname", required_argument, 0, 'H' },
- { "hostname", required_argument, 0, 'h' },
- { "fqdn", required_argument, 0, 'F' },
- { "interface", required_argument, 0, 'i' },
- { "now", no_argument, 0, 'n' },
- { "pidfile", required_argument, 0, 'p' },
- { "quit", no_argument, 0, 'q' },
- { "release", no_argument, 0, 'R' },
- { "request", required_argument, 0, 'r' },
- { "script", required_argument, 0, 's' },
- { "timeout", required_argument, 0, 'T' },
- { "version", no_argument, 0, 'v' },
- { "retries", required_argument, 0, 't' },
- { 0, 0, 0, 0 }
+ OPT_C = 1 << 0,
+ OPT_V = 1 << 1,
+ OPT_H = 1 << 2,
+ OPT_h = 1 << 3,
+ OPT_F = 1 << 4,
+ OPT_i = 1 << 5,
+ OPT_n = 1 << 6,
+ OPT_p = 1 << 7,
+ OPT_q = 1 << 8,
+ OPT_R = 1 << 9,
+ OPT_r = 1 << 10,
+ OPT_s = 1 << 11,
+ OPT_T = 1 << 12,
+ OPT_t = 1 << 13,
+ OPT_S = 1 << 14,
+ OPT_A = 1 << 15,
+ OPT_O = 1 << 16,
+ OPT_o = 1 << 17,
+ OPT_x = 1 << 18,
+ OPT_f = 1 << 19,
+/* The rest has variable bit positions, need to be clever */
+ OPTBIT_f = 19,
+ USE_FOR_MMU( OPTBIT_b,)
+ IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
+ IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
+ USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
+ IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
+ IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
};
-#endif
+
/* Default options. */
+ IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
+ IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
client_config.interface = "eth0";
- client_config.script = DEFAULT_SCRIPT;
- client_config.retries = 3;
- client_config.timeout = 3;
+ client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
+ str_V = "udhcp "BB_VER;
/* Parse command line */
- opt_complementary = "?:c--C:C--c" // mutually exclusive
- ":hH:Hh"; // -h and -H are the same
-#if ENABLE_GETOPT_LONG
- applet_long_options = arg_options;
+ /* O,x: list; -T,-t,-A take numeric param */
+ opt_complementary = "O::x::T+:t+:A+"
+#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
+ ":vv"
+#endif
+ ;
+ IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
+ opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:f"
+ USE_FOR_MMU("b")
+ IF_FEATURE_UDHCPC_ARPING("a")
+ IF_FEATURE_UDHCP_PORT("P:")
+ "v"
+ , &str_V, &str_h, &str_h, &str_F
+ , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
+ , &client_config.script /* s */
+ , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
+ , &list_O
+ , &list_x
+ IF_FEATURE_UDHCP_PORT(, &str_P)
+#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
+ , &dhcp_verbose
#endif
- opt = getopt32(argc, argv, "c:CV:fbH:h:F:i:np:qRr:s:T:t:v",
- &str_c, &str_V, &str_h, &str_h, &str_F,
- &client_config.interface, &client_config.pidfile, &str_r,
- &client_config.script, &str_T, &str_t
);
-
- if (opt & OPT_c)
- client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
- if (opt & OPT_C)
- no_clientid = 1;
- if (opt & OPT_V)
- client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
- if (opt & OPT_f)
- client_config.foreground = 1;
- if (opt & OPT_b)
- client_config.background_if_no_lease = 1;
- if (opt & OPT_h)
+ if (opt & (OPT_h|OPT_H))
client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
if (opt & OPT_F) {
+ /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
- /* Flags: 0000NEOS
- S: 1 => Client requests Server to update A RR in DNS as well as PTR
- O: 1 => Server indicates to client that DNS has been updated regardless
- E: 1 => Name data is DNS format, i.e. <4>host<6>domain<4>com<0> not "host.domain.com"
- N: 1 => Client requests Server to not update DNS
- */
+ /* Flag bits: 0000NEOS
+ * S: 1 = Client requests server to update A RR in DNS as well as PTR
+ * O: 1 = Server indicates to client that DNS has been updated regardless
+ * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
+ * not "host.domain.com". Format 0 is obsolete.
+ * N: 1 = Client requests server to not update DNS (S must be 0 then)
+ * Two [0] bytes which follow are deprecated and must be 0.
+ */
client_config.fqdn[OPT_DATA + 0] = 0x1;
- /* client_config.fqdn[OPT_DATA + 1] = 0; - redundant */
- /* client_config.fqdn[OPT_DATA + 2] = 0; - redundant */
+ /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
+ /*client_config.fqdn[OPT_DATA + 2] = 0; */
}
- // if (opt & OPT_i) client_config.interface = ...
- if (opt & OPT_n)
- client_config.abort_if_no_lease = 1;
- // if (opt & OPT_p) client_config.pidfile = ...
- if (opt & OPT_q)
- client_config.quit_after_lease = 1;
- if (opt & OPT_R)
- client_config.release_on_quit = 1;
if (opt & OPT_r)
requested_ip = inet_addr(str_r);
- // if (opt & OPT_s) client_config.script = ...
- if (opt & OPT_T)
- client_config.timeout = xatoi_u(str_T);
- if (opt & OPT_t)
- client_config.retries = xatoi_u(str_t);
- if (opt & OPT_v) {
- printf("version %s\n\n", BB_VER);
- return 0;
+#if ENABLE_FEATURE_UDHCP_PORT
+ if (opt & OPT_P) {
+ CLIENT_PORT = xatou16(str_P);
+ SERVER_PORT = CLIENT_PORT - 1;
+ }
+#endif
+ if (opt & OPT_o)
+ client_config.no_default_options = 1;
+ while (list_O) {
+ char *optstr = llist_pop(&list_O);
+ unsigned n = udhcp_option_idx(optstr);
+ n = dhcp_optflags[n].code;
+ client_config.opt_mask[n >> 3] |= 1 << (n & 7);
+ }
+ while (list_x) {
+ char *optstr = llist_pop(&list_x);
+ char *colon = strchr(optstr, ':');
+ if (colon)
+ *colon = ' ';
+ /* now it looks similar to udhcpd's config file line:
+ * "optname optval", using the common routine: */
+ udhcp_str2optset(optstr, &client_config.options);
}
- /* Start the log, sanitize fd's, and write a pid file */
- udhcp_start_log_and_pid(client_config.pidfile);
-
- if (read_interface(client_config.interface, &client_config.ifindex,
- NULL, client_config.arp) < 0)
+ if (udhcp_read_interface(client_config.interface,
+ &client_config.ifindex,
+ NULL,
+ client_config.client_mac)
+ ) {
return 1;
+ }
- /* if not set, and not suppressed, setup the default client ID */
- if (!client_config.clientid && !no_clientid) {
+ if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) {
+ /* not suppressed and not set, set the default client ID */
client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
- client_config.clientid[OPT_DATA] = 1;
- memcpy(client_config.clientid + OPT_DATA+1, client_config.arp, 6);
+ client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
+ memcpy(client_config.clientid + OPT_DATA+1, client_config.client_mac, 6);
+ }
+ if (str_V[0] != '\0')
+ client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
+#if !BB_MMU
+ /* on NOMMU reexec (i.e., background) early */
+ if (!(opt & OPT_f)) {
+ bb_daemonize_or_rexec(0 /* flags */, argv);
+ logmode = LOGMODE_NONE;
+ }
+#endif
+ if (opt & OPT_S) {
+ openlog(applet_name, LOG_PID, LOG_DAEMON);
+ logmode |= LOGMODE_SYSLOG;
}
- if (!client_config.vendorclass)
- client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0);
-
- /* setup the signal pipe */
+ /* Make sure fd 0,1,2 are open */
+ bb_sanitize_stdio();
+ /* Equivalent of doing a fflush after every \n */
+ setlinebuf(stdout);
+ /* Create pidfile */
+ write_pidfile(client_config.pidfile);
+ /* Goes to stdout (unless NOMMU) and possibly syslog */
+ bb_info_msg("%s (v"BB_VER") started", applet_name);
+ /* Set up the signal pipe */
udhcp_sp_setup();
+ /* We want random_xid to be random... */
+ srand(monotonic_us());
state = INIT_SELECTING;
udhcp_run_script(NULL, "deconfig");
- change_mode(LISTEN_RAW);
+ change_listen_mode(LISTEN_RAW);
+ packet_num = 0;
+ timeout = 0;
+ already_waited_sec = 0;
+ /* Main event loop. select() waits on signal pipe and possibly
+ * on sockfd.
+ * "continue" statements in code below jump to the top of the loop.
+ */
for (;;) {
- tv.tv_sec = timeout - uptime();
- tv.tv_usec = 0;
+ /* silence "uninitialized!" warning */
+ unsigned timestamp_before_wait = timestamp_before_wait;
- if (listen_mode != LISTEN_NONE && fd < 0) {
- if (listen_mode == LISTEN_KERNEL)
- fd = listen_socket(INADDR_ANY, CLIENT_PORT, client_config.interface);
- else
- fd = raw_socket(client_config.ifindex);
- }
- max_fd = udhcp_sp_fd_set(&rfds, fd);
+ //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
+
+ /* Was opening raw or udp socket here
+ * if (listen_mode != LISTEN_NONE && sockfd < 0),
+ * but on fast network renew responses return faster
+ * than we open sockets. Thus this code is moved
+ * to change_listen_mode(). Thus we open listen socket
+ * BEFORE we send renew request (see "case BOUND:"). */
- if (tv.tv_sec > 0) {
- DEBUG("Waiting on select...");
+ max_fd = udhcp_sp_fd_set(&rfds, sockfd);
+
+ tv.tv_sec = timeout - already_waited_sec;
+ tv.tv_usec = 0;
+ retval = 0;
+ /* If we already timed out, fall through with retval = 0, else... */
+ if ((int)tv.tv_sec > 0) {
+ timestamp_before_wait = (unsigned)monotonic_sec();
+ log1("Waiting on select...");
retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
- } else retval = 0; /* If we already timed out, fall through */
+ if (retval < 0) {
+ /* EINTR? A signal was caught, don't panic */
+ if (errno == EINTR) {
+ already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
+ continue;
+ }
+ /* Else: an error occured, panic! */
+ bb_perror_msg_and_die("select");
+ }
+ }
- now = uptime();
+ /* If timeout dropped to zero, time to become active:
+ * resend discover/renew/whatever
+ */
if (retval == 0) {
- /* timeout dropped to zero */
+ /* When running on a bridge, the ifindex may have changed
+ * (e.g. if member interfaces were added/removed
+ * or if the status of the bridge changed).
+ * Refresh ifindex and client_mac:
+ */
+ udhcp_read_interface(client_config.interface,
+ &client_config.ifindex,
+ NULL,
+ client_config.client_mac);
+
+ /* We will restart the wait in any case */
+ already_waited_sec = 0;
+
switch (state) {
case INIT_SELECTING:
- if (packet_num < client_config.retries) {
+ if (packet_num < discover_retries) {
if (packet_num == 0)
xid = random_xid();
-
- /* send discover packet */
- send_discover(xid, requested_ip); /* broadcast */
-
- timeout = now + client_config.timeout;
+ /* broadcast */
+ send_discover(xid, requested_ip);
+ timeout = discover_timeout;
packet_num++;
- } else {
- udhcp_run_script(NULL, "leasefail");
- if (client_config.background_if_no_lease) {
- bb_info_msg("No lease, forking to background");
- client_background();
- } else if (client_config.abort_if_no_lease) {
- bb_info_msg("No lease, failing");
- return 1;
- }
- /* wait to try again */
- packet_num = 0;
- timeout = now + 60;
+ continue;
+ }
+ leasefail:
+ udhcp_run_script(NULL, "leasefail");
+#if BB_MMU /* -b is not supported on NOMMU */
+ if (opt & OPT_b) { /* background if no lease */
+ bb_info_msg("No lease, forking to background");
+ client_background();
+ /* do not background again! */
+ opt = ((opt & ~OPT_b) | OPT_f);
+ } else
+#endif
+ if (opt & OPT_n) { /* abort if no lease */
+ bb_info_msg("No lease, failing");
+ retval = 1;
+ goto ret;
}
- break;
- case RENEW_REQUESTED:
+ /* wait before trying again */
+ timeout = tryagain_timeout;
+ packet_num = 0;
+ continue;
case REQUESTING:
- if (packet_num < client_config.retries) {
- /* send request packet */
- if (state == RENEW_REQUESTED)
- send_renew(xid, server_addr, requested_ip); /* unicast */
- else send_selecting(xid, server_addr, requested_ip); /* broadcast */
-
- timeout = now + ((packet_num == 2) ? 10 : 2);
+ if (packet_num < discover_retries) {
+ /* send broadcast select packet */
+ send_select(xid, server_addr, requested_ip);
+ timeout = discover_timeout;
packet_num++;
- } else {
- /* timed out, go back to init state */
- if (state == RENEW_REQUESTED) udhcp_run_script(NULL, "deconfig");
- state = INIT_SELECTING;
- timeout = now;
- packet_num = 0;
- change_mode(LISTEN_RAW);
+ continue;
}
- break;
+ /* Timed out, go back to init state.
+ * "discover...select...discover..." loops
+ * were seen in the wild. Treat them similarly
+ * to "no response to discover" case */
+ change_listen_mode(LISTEN_RAW);
+ state = INIT_SELECTING;
+ goto leasefail;
case BOUND:
- /* Lease is starting to run out, time to enter renewing state */
+ /* 1/2 lease passed, enter renewing state */
state = RENEWING;
- change_mode(LISTEN_KERNEL);
- DEBUG("Entering renew state");
+ change_listen_mode(LISTEN_KERNEL);
+ log1("Entering renew state");
/* fall right through */
+ case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
+ case_RENEW_REQUESTED:
case RENEWING:
- /* Either set a new T1, or enter REBINDING state */
- if ((t2 - t1) <= (lease / 14400 + 1)) {
- /* timed out, enter rebinding state */
- state = REBINDING;
- timeout = now + (t2 - t1);
- DEBUG("Entering rebinding state");
- } else {
- /* send a request packet */
- send_renew(xid, server_addr, requested_ip); /* unicast */
-
- t1 = (t2 - t1) / 2 + t1;
- timeout = t1 + start;
+ if (timeout > 60) {
+ /* send an unicast renew request */
+ /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
+ * a new UDP socket for sending inside send_renew.
+ * I hazard to guess existing listening socket
+ * is somehow conflicting with it, but why is it
+ * not deterministic then?! Strange.
+ * Anyway, it does recover by eventually failing through
+ * into INIT_SELECTING state.
+ */
+ send_renew(xid, server_addr, requested_ip);
+ timeout >>= 1;
+ continue;
}
- break;
+ /* Timed out, enter rebinding state */
+ log1("Entering rebinding state");
+ state = REBINDING;
+ /* fall right through */
case REBINDING:
- /* Either set a new T2, or enter INIT state */
- if ((lease - t2) <= (lease / 14400 + 1)) {
- /* timed out, enter init state */
- state = INIT_SELECTING;
- bb_info_msg("Lease lost, entering init state");
- udhcp_run_script(NULL, "deconfig");
- timeout = now;
- packet_num = 0;
- change_mode(LISTEN_RAW);
- } else {
- /* send a request packet */
- send_renew(xid, 0, requested_ip); /* broadcast */
-
- t2 = (lease - t2) / 2 + t2;
- timeout = t2 + start;
+ /* Switch to bcast receive */
+ change_listen_mode(LISTEN_RAW);
+ /* Lease is *really* about to run out,
+ * try to find DHCP server using broadcast */
+ if (timeout > 0) {
+ /* send a broadcast renew request */
+ send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
+ timeout >>= 1;
+ continue;
}
- break;
- case RELEASED:
- /* yah, I know, *you* say it would never happen */
- timeout = 0x7fffffff;
- break;
+ /* Timed out, enter init state */
+ bb_info_msg("Lease lost, entering init state");
+ udhcp_run_script(NULL, "deconfig");
+ state = INIT_SELECTING;
+ /*timeout = 0; - already is */
+ packet_num = 0;
+ continue;
+ /* case RELEASED: */
}
- } else if (retval > 0 && listen_mode != LISTEN_NONE && FD_ISSET(fd, &rfds)) {
- /* a packet is ready, read it */
+ /* yah, I know, *you* say it would never happen */
+ timeout = INT_MAX;
+ continue; /* back to main loop */
+ } /* if select timed out */
- if (listen_mode == LISTEN_KERNEL)
- len = udhcp_get_packet(&packet, fd);
- else len = get_raw_packet(&packet, fd);
+ /* select() didn't timeout, something happened */
- if (len == -1 && errno != EINTR) {
- DEBUG("error on read, %s, reopening socket", strerror(errno));
- change_mode(listen_mode); /* just close and reopen */
- }
- if (len < 0) continue;
+ /* Is it a signal? */
+ /* note: udhcp_sp_read checks FD_ISSET before reading */
+ switch (udhcp_sp_read(&rfds)) {
+ case SIGUSR1:
+ perform_renew();
+ if (state == RENEW_REQUESTED)
+ goto case_RENEW_REQUESTED;
+ /* Start things over */
+ packet_num = 0;
+ /* Kill any timeouts, user wants this to hurry along */
+ timeout = 0;
+ continue;
+ case SIGUSR2:
+ perform_release(requested_ip, server_addr);
+ timeout = INT_MAX;
+ continue;
+ case SIGTERM:
+ bb_info_msg("Received SIGTERM");
+ if (opt & OPT_R) /* release on quit */
+ perform_release(requested_ip, server_addr);
+ goto ret0;
+ }
- if (packet.xid != xid) {
- DEBUG("Ignoring XID %lx (our xid is %lx)",
- (unsigned long) packet.xid, xid);
- continue;
- }
+ /* Is it a packet? */
+ if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
+ continue; /* no */
- /* Ignore packets that aren't for us */
- if (memcmp(packet.chaddr, client_config.arp, 6)) {
- DEBUG("Packet does not have our chaddr - ignoring");
- continue;
- }
+ {
+ int len;
- if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
- bb_error_msg("cannot get option from packet - ignoring");
+ /* A packet is ready, read it */
+ if (listen_mode == LISTEN_KERNEL)
+ len = udhcp_recv_kernel_packet(&packet, sockfd);
+ else
+ len = udhcp_recv_raw_packet(&packet, sockfd);
+ if (len == -1) {
+ /* Error is severe, reopen socket */
+ bb_info_msg("Read error: %s, reopening socket", strerror(errno));
+ sleep(discover_timeout); /* 3 seconds by default */
+ change_listen_mode(listen_mode); /* just close and reopen */
+ }
+ /* If this packet will turn out to be unrelated/bogus,
+ * we will go back and wait for next one.
+ * Be sure timeout is properly decreased. */
+ already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
+ if (len < 0)
continue;
+ }
+
+ if (packet.xid != xid) {
+ log1("xid %x (our is %x), ignoring packet",
+ (unsigned)packet.xid, (unsigned)xid);
+ continue;
+ }
+
+ /* Ignore packets that aren't for us */
+ if (packet.hlen != 6
+ || memcmp(packet.chaddr, client_config.client_mac, 6) != 0
+ ) {
+//FIXME: need to also check that last 10 bytes are zero
+ log1("chaddr does not match, ignoring packet"); // log2?
+ continue;
+ }
+
+ message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
+ if (message == NULL) {
+ bb_error_msg("no message type option, ignoring packet");
+ continue;
+ }
+
+ switch (state) {
+ case INIT_SELECTING:
+ /* Must be a DHCPOFFER to one of our xid's */
+ if (*message == DHCPOFFER) {
+ /* TODO: why we don't just fetch server's IP from IP header? */
+ temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
+ if (!temp) {
+ bb_error_msg("no server ID in message");
+ continue;
+ /* still selecting - this server looks bad */
+ }
+ /* it IS unaligned sometimes, don't "optimize" */
+ move_from_unaligned32(server_addr, temp);
+ /*xid = packet.xid; - already is */
+ requested_ip = packet.yiaddr;
+
+ /* enter requesting state */
+ state = REQUESTING;
+ timeout = 0;
+ packet_num = 0;
+ already_waited_sec = 0;
}
+ continue;
+ case REQUESTING:
+ case RENEWING:
+ case RENEW_REQUESTED:
+ case REBINDING:
+ if (*message == DHCPACK) {
+ temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
+ if (!temp) {
+ bb_error_msg("no lease time with ACK, using 1 hour lease");
+ lease_seconds = 60 * 60;
+ } else {
+ /* it IS unaligned sometimes, don't "optimize" */
+ move_from_unaligned32(lease_seconds, temp);
+ lease_seconds = ntohl(lease_seconds);
+ lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
+ if (lease_seconds < 10) /* and not too small */
+ lease_seconds = 10;
+ }
+#if ENABLE_FEATURE_UDHCPC_ARPING
+ if (opt & OPT_a) {
+/* RFC 2131 3.1 paragraph 5:
+ * "The client receives the DHCPACK message with configuration
+ * parameters. The client SHOULD perform a final check on the
+ * parameters (e.g., ARP for allocated network address), and notes
+ * the duration of the lease specified in the DHCPACK message. At this
+ * point, the client is configured. If the client detects that the
+ * address is already in use (e.g., through the use of ARP),
+ * the client MUST send a DHCPDECLINE message to the server and restarts
+ * the configuration process..." */
+ if (!arpping(packet.yiaddr,
+ NULL,
+ (uint32_t) 0,
+ client_config.client_mac,
+ client_config.interface)
+ ) {
+ bb_info_msg("Offered address is in use "
+ "(got ARP reply), declining");
+ send_decline(xid, server_addr, packet.yiaddr);
- switch (state) {
- case INIT_SELECTING:
- /* Must be a DHCPOFFER to one of our xid's */
- if (*message == DHCPOFFER) {
- temp = get_option(&packet, DHCP_SERVER_ID);
- if (temp) {
- /* can be misaligned, thus memcpy */
- memcpy(&server_addr, temp, 4);
- xid = packet.xid;
- requested_ip = packet.yiaddr;
-
- /* enter requesting state */
- state = REQUESTING;
- timeout = now;
+ if (state != REQUESTING)
+ udhcp_run_script(NULL, "deconfig");
+ change_listen_mode(LISTEN_RAW);
+ state = INIT_SELECTING;
+ requested_ip = 0;
+ timeout = tryagain_timeout;
packet_num = 0;
- } else {
- bb_error_msg("no server ID in message");
+ already_waited_sec = 0;
+ continue; /* back to main loop */
}
}
- break;
- case RENEW_REQUESTED:
- case REQUESTING:
- case RENEWING:
- case REBINDING:
- if (*message == DHCPACK) {
- temp = get_option(&packet, DHCP_LEASE_TIME);
- if (!temp) {
- bb_error_msg("no lease time with ACK, using 1 hour lease");
- lease = 60 * 60;
- } else {
- /* can be misaligned, thus memcpy */
- memcpy(&lease, temp, 4);
- lease = ntohl(lease);
- }
-
- /* enter bound state */
- t1 = lease / 2;
-
- /* little fixed point for n * .875 */
- t2 = (lease * 0x7) >> 3;
+#endif
+ /* enter bound state */
+ timeout = lease_seconds / 2;
+ {
+ struct in_addr temp_addr;
temp_addr.s_addr = packet.yiaddr;
- bb_info_msg("Lease of %s obtained, lease time %ld",
- inet_ntoa(temp_addr), lease);
- start = now;
- timeout = t1 + start;
- requested_ip = packet.yiaddr;
- udhcp_run_script(&packet,
- ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
-
- state = BOUND;
- change_mode(LISTEN_NONE);
- if (client_config.quit_after_lease) {
- if (client_config.release_on_quit)
- perform_release();
- return 0;
- }
- if (!client_config.foreground)
- client_background();
-
- } else if (*message == DHCPNAK) {
- /* return to init state */
- bb_info_msg("Received DHCP NAK");
- udhcp_run_script(&packet, "nak");
- if (state != REQUESTING)
- udhcp_run_script(NULL, "deconfig");
- state = INIT_SELECTING;
- timeout = now;
- requested_ip = 0;
- packet_num = 0;
- change_mode(LISTEN_RAW);
- sleep(3); /* avoid excessive network traffic */
+ bb_info_msg("Lease of %s obtained, lease time %u",
+ inet_ntoa(temp_addr), (unsigned)lease_seconds);
+ }
+ requested_ip = packet.yiaddr;
+ udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
+
+ state = BOUND;
+ change_listen_mode(LISTEN_NONE);
+ if (opt & OPT_q) { /* quit after lease */
+ if (opt & OPT_R) /* release on quit */
+ perform_release(requested_ip, server_addr);
+ goto ret0;
}
- break;
- /* case BOUND, RELEASED: - ignore all packets */
+ /* future renew failures should not exit (JM) */
+ opt &= ~OPT_n;
+#if BB_MMU /* NOMMU case backgrounded earlier */
+ if (!(opt & OPT_f)) {
+ client_background();
+ /* do not background again! */
+ opt = ((opt & ~OPT_b) | OPT_f);
+ }
+#endif
+ already_waited_sec = 0;
+ continue; /* back to main loop */
}
- } else if (retval > 0 && (sig = udhcp_sp_read(&rfds))) {
- switch (sig) {
- case SIGUSR1:
- perform_renew();
- break;
- case SIGUSR2:
- perform_release();
- break;
- case SIGTERM:
- bb_info_msg("Received SIGTERM");
- if (client_config.release_on_quit)
- perform_release();
- return 0;
+ if (*message == DHCPNAK) {
+ /* return to init state */
+ bb_info_msg("Received DHCP NAK");
+ udhcp_run_script(&packet, "nak");
+ if (state != REQUESTING)
+ udhcp_run_script(NULL, "deconfig");
+ change_listen_mode(LISTEN_RAW);
+ sleep(3); /* avoid excessive network traffic */
+ state = INIT_SELECTING;
+ requested_ip = 0;
+ timeout = 0;
+ packet_num = 0;
+ already_waited_sec = 0;
}
- } else if (retval == -1 && errno == EINTR) {
- /* a signal was caught */
- } else {
- /* An error occured */
- bb_perror_msg("select");
+ continue;
+ /* case BOUND: - ignore all packets */
+ /* case RELEASED: - ignore all packets */
}
+ /* back to main loop */
+ } /* for (;;) - main loop ends */
- }
- return 0;
+ ret0:
+ retval = 0;
+ ret:
+ /*if (client_config.pidfile) - remove_pidfile has its own check */
+ remove_pidfile(client_config.pidfile);
+ return retval;
}
projects / oweals / busybox.git / blobdiff