select.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*
* SELECTING state of the client state machine.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <sys/types.h>
#include <stdlib.h>
#include <stdio.h>
#include <strings.h>
#include <time.h>
#include <limits.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <net/route.h>
#include <net/if.h>
#include <netinet/dhcp.h>
#include <netinet/udp.h>
#include <netinet/ip_var.h>
#include <netinet/udp_var.h>
#include <stropts.h> /* FLUSHR/FLUSHW */
#include <dhcpmsg.h>
#include "states.h"
#include "agent.h"
#include "util.h"
#include "interface.h"
#include "packet.h"
#include "defaults.h"
static iu_eh_callback_t dhcp_collect_offers;
static stop_func_t stop_selecting;
/*
* dhcp_start(): starts DHCP on an interface
*
* input: iu_tq_t *: unused
* void *: the interface to start DHCP on
* output: void
*/
/* ARGSUSED */
void
dhcp_start(iu_tq_t *tqp, void *arg)
{
struct ifslist *ifsp = (struct ifslist *)arg;
if (check_ifs(ifsp) == 0) {
(void) release_ifs(ifsp);
return;
}
dhcpmsg(MSG_VERBOSE, "starting DHCP on %s", ifsp->if_name);
dhcp_selecting(ifsp);
}
/*
* dhcp_selecting(): sends a DISCOVER and sets up reception for an OFFER
*
* input: struct ifslist *: the interface to send the DISCOVER on, ...
* output: void
*/
void
dhcp_selecting(struct ifslist *ifsp)
{
dhcp_pkt_t *dpkt;
const char *reqhost;
char hostfile[PATH_MAX + 1];
/*
* we first set up to collect OFFER packets as they arrive.
* we then send out DISCOVER probes. then we wait at a
* user-tunable number of seconds before seeing if OFFERs have
* come in response to our DISCOVER. if none have come in, we
* continue to wait, sending out our DISCOVER probes with
* exponential backoff. if an OFFER is never received, we
* will wait forever (note that since we're event-driven
* though, we're still able to service other interfaces.)
*
* note that we do an reset_ifs() here because we may be
* landing in dhcp_selecting() as a result of restarting DHCP,
* so the ifs may not be fresh.
*/
reset_ifs(ifsp);
ifsp->if_state = SELECTING;
if ((ifsp->if_offer_id = iu_register_event(eh, ifsp->if_dlpi_fd, POLLIN,
dhcp_collect_offers, ifsp)) == -1) {
dhcpmsg(MSG_ERROR, "dhcp_selecting: cannot register to collect "
"OFFER packets, reverting to INIT on %s",
ifsp->if_name);
ifsp->if_state = INIT;
ifsp->if_dflags |= DHCP_IF_FAILED;
ipc_action_finish(ifsp, DHCP_IPC_E_MEMORY);
async_finish(ifsp);
return;
} else
hold_ifs(ifsp);
if (iu_schedule_timer(tq, ifsp->if_offer_wait, dhcp_requesting,
ifsp) == -1) {
dhcpmsg(MSG_ERROR, "dhcp_selecting: cannot schedule to read "
"OFFER packets");
if (iu_unregister_event(eh, ifsp->if_offer_id, NULL) != 0) {
ifsp->if_offer_id = -1;
(void) release_ifs(ifsp);
}
ifsp->if_state = INIT;
ifsp->if_dflags |= DHCP_IF_FAILED;
ipc_action_finish(ifsp, DHCP_IPC_E_MEMORY);
async_finish(ifsp);
return;
} else
hold_ifs(ifsp);
/*
* Assemble DHCPDISCOVER message. The max dhcp message size
* option is set to the interface max, minus the size of the udp and
* ip headers.
*/
dpkt = init_pkt(ifsp, DISCOVER);
add_pkt_opt16(dpkt, CD_MAX_DHCP_SIZE, htons(ifsp->if_max -
sizeof (struct udpiphdr)));
add_pkt_opt32(dpkt, CD_LEASE_TIME, htonl(DHCP_PERM));
add_pkt_opt(dpkt, CD_CLASS_ID, class_id, class_id_len);
add_pkt_opt(dpkt, CD_REQUEST_LIST, ifsp->if_prl, ifsp->if_prllen);
if (df_get_bool(ifsp->if_name, DF_REQUEST_HOSTNAME)) {
dhcpmsg(MSG_DEBUG, "dhcp_selecting: DF_REQUEST_HOSTNAME");
(void) snprintf(hostfile, sizeof (hostfile), "/etc/hostname.%s",
ifsp->if_name);
if ((reqhost = iffile_to_hostname(hostfile)) != NULL) {
dhcpmsg(MSG_DEBUG, "dhcp_selecting: host %s", reqhost);
if ((ifsp->if_reqhost = strdup(reqhost)) != NULL)
add_pkt_opt(dpkt, CD_HOSTNAME, ifsp->if_reqhost,
strlen(ifsp->if_reqhost));
else
dhcpmsg(MSG_WARNING, "dhcp_selecting: cannot"
" allocate memory for host name option");
}
}
add_pkt_opt(dpkt, CD_END, NULL, 0);
(void) send_pkt(ifsp, dpkt, htonl(INADDR_BROADCAST), stop_selecting);
}
/*
* dhcp_collect_offers(): collects incoming OFFERs to a DISCOVER
*
* input: iu_eh_t *: unused
* int: the file descriptor the OFFER arrived on
* short: unused
* iu_event_id_t: the id of this event callback with the handler
* void *: the interface that received the OFFER
* output: void
*/
/* ARGSUSED */
static void
dhcp_collect_offers(iu_eh_t *eh, int fd, short events, iu_event_id_t id,
void *arg)
{
struct ifslist *ifsp = (struct ifslist *)arg;
if (verify_ifs(ifsp) == 0) {
(void) ioctl(fd, I_FLUSH, FLUSHR|FLUSHW);
return;
}
/*
* DHCP_PUNTYPED messages are BOOTP server responses.
*/
(void) recv_pkt(ifsp, fd, DHCP_POFFER|DHCP_PUNTYPED, B_TRUE);
}
/*
* stop_selecting(): decides when to stop retransmitting DISCOVERs (never)
*
* input: struct ifslist *: the interface DISCOVERs are being sent on
* unsigned int: the number of DISCOVERs sent so far
* output: boolean_t: B_TRUE if retransmissions should stop
*/
/* ARGSUSED */
static boolean_t
stop_selecting(struct ifslist *ifsp, unsigned int n_discovers)
{
return (B_FALSE);
}