/* vi: set sw=4 ts=4: */
/*
- * udhcp Server
+ * udhcp server
* Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au>
* Chris Trew <ctrew@moreton.com.au>
*
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
+//usage:#define udhcpd_trivial_usage
+//usage: "[-fS]" IF_FEATURE_UDHCP_PORT(" [-P N]") " [CONFFILE]"
+//usage:#define udhcpd_full_usage "\n\n"
+//usage: "DHCP server\n"
+//usage: "\n -f Run in foreground"
+//usage: "\n -S Log to syslog too"
+//usage: IF_FEATURE_UDHCP_PORT(
+//usage: "\n -P N Use port N (default 67)"
+//usage: )
+
#include <syslog.h>
#include "common.h"
#include "dhcpc.h"
}
/* We got a DHCP DISCOVER. Send an OFFER. */
-static void send_offer(struct dhcp_packet *oldpacket, uint32_t static_lease_nip, struct dyn_lease *lease)
+/* NOINLINE: limit stack usage in caller */
+static NOINLINE void send_offer(struct dhcp_packet *oldpacket,
+ uint32_t static_lease_nip,
+ struct dyn_lease *lease,
+ uint8_t *requested_ip_opt)
{
struct dhcp_packet packet;
uint32_t lease_time_sec;
if (!static_lease_nip) {
/* We have no static lease for client's chaddr */
uint32_t req_nip;
- uint8_t *req_ip_opt;
const char *p_host_name;
if (lease) {
packet.yiaddr = lease->lease_nip;
}
/* Or: if client has requested an IP */
- else if ((req_ip_opt = udhcp_get_option(oldpacket, DHCP_REQUESTED_IP)) != NULL
+ else if (requested_ip_opt != NULL
/* (read IP) */
- && (move_from_unaligned32(req_nip, req_ip_opt), 1)
+ && (move_from_unaligned32(req_nip, requested_ip_opt), 1)
/* and the IP is in the lease range */
&& ntohl(req_nip) >= server_config.start_ip
&& ntohl(req_nip) <= server_config.end_ip
send_packet(&packet, /*force_bcast:*/ 0);
}
-static void send_NAK(struct dhcp_packet *oldpacket)
+/* NOINLINE: limit stack usage in caller */
+static NOINLINE void send_NAK(struct dhcp_packet *oldpacket)
{
struct dhcp_packet packet;
send_packet(&packet, /*force_bcast:*/ 1);
}
-static void send_ACK(struct dhcp_packet *oldpacket, uint32_t yiaddr)
+/* NOINLINE: limit stack usage in caller */
+static NOINLINE void send_ACK(struct dhcp_packet *oldpacket, uint32_t yiaddr)
{
struct dhcp_packet packet;
uint32_t lease_time_sec;
}
}
-static void send_inform(struct dhcp_packet *oldpacket)
+/* NOINLINE: limit stack usage in caller */
+static NOINLINE void send_inform(struct dhcp_packet *oldpacket)
{
struct dhcp_packet packet;
- /* "The server responds to a DHCPINFORM message by sending a DHCPACK
+ /* "If a client has obtained a network address through some other means
+ * (e.g., manual configuration), it may use a DHCPINFORM request message
+ * to obtain other local configuration parameters. Servers receiving a
+ * DHCPINFORM message construct a DHCPACK message with any local
+ * configuration parameters appropriate for the client without:
+ * allocating a new address, checking for an existing binding, filling
+ * in 'yiaddr' or including lease time parameters. The servers SHOULD
+ * unicast the DHCPACK reply to the address given in the 'ciaddr' field
+ * of the DHCPINFORM message.
+ * ...
+ * The server responds to a DHCPINFORM message by sending a DHCPACK
* message directly to the address given in the 'ciaddr' field
* of the DHCPINFORM message. The server MUST NOT send a lease
* expiration time to the client and SHOULD NOT fill in 'yiaddr'."
*/
+//TODO: do a few sanity checks: is ciaddr set?
+//Better yet: is ciaddr == IP source addr?
init_packet(&packet, oldpacket, DHCPACK);
add_server_options(&packet);
int udhcpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int udhcpd_main(int argc UNUSED_PARAM, char **argv)
{
- fd_set rfds;
int server_socket = -1, retval, max_sock;
- struct dhcp_packet packet;
uint8_t *state;
- uint32_t static_lease_nip;
unsigned timeout_end;
unsigned num_ips;
unsigned opt;
struct option_set *option;
- struct dyn_lease *lease, fake_lease;
IF_FEATURE_UDHCP_PORT(char *str_P;)
#if ENABLE_FEATURE_UDHCP_PORT
#endif
opt = getopt32(argv, "fSv"
IF_FEATURE_UDHCP_PORT("P:", &str_P)
-#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
- , &dhcp_verbose
-#endif
+ IF_UDHCP_VERBOSE(, &dhcp_verbose)
);
- argv += optind;
if (!(opt & 1)) { /* no -f */
bb_daemonize_or_rexec(0, argv);
logmode = LOGMODE_NONE;
}
+ /* update argv after the possible vfork+exec in daemonize */
+ argv += optind;
if (opt & 2) { /* -S */
openlog(applet_name, LOG_PID, LOG_DAEMON);
logmode |= LOGMODE_SYSLOG;
}
#if ENABLE_FEATURE_UDHCP_PORT
- if (opt & 4) { /* -P */
+ if (opt & 8) { /* -P */
SERVER_PORT = xatou16(str_P);
CLIENT_PORT = SERVER_PORT + 1;
}
/* Setup the signal pipe */
udhcp_sp_setup();
+ continue_with_autotime:
timeout_end = monotonic_sec() + server_config.auto_time;
while (1) { /* loop until universe collapses */
+ fd_set rfds;
+ struct dhcp_packet packet;
int bytes;
struct timeval tv;
uint8_t *server_id_opt;
- uint8_t *requested_opt;
+ uint8_t *requested_ip_opt;
uint32_t requested_nip = requested_nip; /* for compiler */
+ uint32_t static_lease_nip;
+ struct dyn_lease *lease, fake_lease;
if (server_socket < 0) {
server_socket = udhcp_listen_socket(/*INADDR_ANY,*/ SERVER_PORT,
}
if (retval == 0) {
write_leases();
- timeout_end = monotonic_sec() + server_config.auto_time;
- continue;
+ goto continue_with_autotime;
}
if (retval < 0 && errno != EINTR) {
log1("Error on select");
bb_info_msg("Received SIGUSR1");
write_leases();
/* why not just reset the timeout, eh */
- timeout_end = monotonic_sec() + server_config.auto_time;
- continue;
+ goto continue_with_autotime;
case SIGTERM:
bb_info_msg("Received SIGTERM");
+ write_leases();
goto ret0;
- case 0: /* no signal: read a packet */
+ case 0: /* no signal: read a packet */
break;
default: /* signal or error (probably EINTR): back to select */
continue;
continue;
}
+ /* Get SERVER_ID if present */
+ server_id_opt = udhcp_get_option(&packet, DHCP_SERVER_ID);
+ if (server_id_opt) {
+ uint32_t server_id_network_order;
+ move_from_unaligned32(server_id_network_order, server_id_opt);
+ if (server_id_network_order != server_config.server_nip) {
+ /* client talks to somebody else */
+ log1("server ID doesn't match, ignoring");
+ continue;
+ }
+ }
+
/* Look for a static/dynamic lease */
static_lease_nip = get_static_nip_by_mac(server_config.static_leases, &packet.chaddr);
if (static_lease_nip) {
lease = find_lease_by_mac(packet.chaddr);
}
- /* Get REQUESTED_IP and SERVER_ID if present */
- server_id_opt = udhcp_get_option(&packet, DHCP_SERVER_ID);
- if (server_id_opt) {
- uint32_t server_id_net;
- move_from_unaligned32(server_id_net, server_id_opt);
- if (server_id_net != server_config.server_nip) {
- /* client talks to somebody else */
- log1("server ID doesn't match, ignoring");
- continue;
- }
- }
- requested_opt = udhcp_get_option(&packet, DHCP_REQUESTED_IP);
- if (requested_opt) {
- move_from_unaligned32(requested_nip, requested_opt);
+ /* Get REQUESTED_IP if present */
+ requested_ip_opt = udhcp_get_option(&packet, DHCP_REQUESTED_IP);
+ if (requested_ip_opt) {
+ move_from_unaligned32(requested_nip, requested_ip_opt);
}
switch (state[0]) {
case DHCPDISCOVER:
log1("Received DISCOVER");
- send_offer(&packet, static_lease_nip, lease);
+ send_offer(&packet, static_lease_nip, lease, requested_ip_opt);
break;
case DHCPREQUEST:
A DHCP server MAY extend a client's lease only if it has local
administrative authority to do so.
*/
- if (!requested_opt) {
+ if (!requested_ip_opt) {
requested_nip = packet.ciaddr;
if (requested_nip == 0) {
log1("no requested IP and no ciaddr, ignoring");
send_ACK(&packet, lease->lease_nip);
break;
}
- if (server_id_opt) {
- /* client was talking specifically to us.
- * "No, we don't have this IP for you". */
+ /* No lease for this MAC, or lease IP != requested IP */
+
+ if (server_id_opt /* client is in SELECTING state */
+ || requested_ip_opt /* client is in INIT-REBOOT state */
+ ) {
+ /* "No, we don't have this IP for you" */
send_NAK(&packet);
- }
+ } /* else: client is in RENEWING or REBINDING, do not answer */
+
break;
case DHCPDECLINE:
*/
log1("Received DECLINE");
if (server_id_opt
- && requested_opt
+ && requested_ip_opt
&& lease /* chaddr matches this lease */
&& requested_nip == lease->lease_nip
) {
projects / oweals / busybox.git / blobdiff