dhclient.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

/*	$OpenBSD: dhclient.c,v 1.62 2004/12/05 18:35:51 deraadt Exp $	*/

/*
 * Copyright 2004 Henning Brauer <[e-mail]>
 * Copyright (c) 1995, 1996, 1997, 1998, 1999
 * The Internet Software Consortium.    All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of The Internet Software Consortium nor the names
 *    of its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This software has been written for the Internet Software Consortium
 * by Ted Lemon <[e-mail]> in cooperation with Vixie
 * Enterprises.  To learn more about the Internet Software Consortium,
 * see ``http://www.vix.com/isc''.  To learn more about Vixie
 * Enterprises, see ``http://www.vix.com''.
 *
 * This client was substantially modified and enhanced by Elliot Poger
 * for use on Linux while he was working on the MosquitoNet project at
 * Stanford.
 *
 * The current version owes much to Elliot's Linux enhancements, but
 * was substantially reorganized and partially rewritten by Ted Lemon
 * so as to use the same networking framework that the Internet Software
 * Consortium DHCP server uses.   Much system-specific configuration code
 * was moved into a shell script so that as support for more operating
 * systems is added, it will not be necessary to port and maintain
 * system-specific configuration code to these operating systems - instead,
 * the shell script can invoke the native tools to accomplish the same
 * purpose.
 */

#include "rosdhcp.h"
#include <winsock2.h>
#include "dhcpd.h"
#include "privsep.h"

#define	PERIOD 0x2e
#define	hyphenchar(c) ((c) == 0x2d)
#define	bslashchar(c) ((c) == 0x5c)
#define	periodchar(c) ((c) == PERIOD)
#define	asterchar(c) ((c) == 0x2a)
#define	alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) || \
	    ((c) >= 0x61 && (c) <= 0x7a))
#define	digitchar(c) ((c) >= 0x30 && (c) <= 0x39)

#define	borderchar(c) (alphachar(c) || digitchar(c))
#define	middlechar(c) (borderchar(c) || hyphenchar(c))
#define	domainchar(c) ((c) > 0x20 && (c) < 0x7f)

unsigned long debug_trace_level = 0; /* DEBUG_ULTRA */
time_t cur_time;
time_t default_lease_time = 43200; /* 12 hours... */

char *path_dhclient_conf = _PATH_DHCLIENT_CONF;
char *path_dhclient_db = NULL;

int log_perror = 1;
int privfd;
//int nullfd = -1;

struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } };
struct in_addr inaddr_any;
struct sockaddr_in sockaddr_broadcast;
unsigned long old_default_route = 0;

/*
 * ASSERT_STATE() does nothing now; it used to be
 * assert (state_is == state_shouldbe).
 */
#define ASSERT_STATE(state_is, state_shouldbe) {}

#define TIME_MAX 2147483647

int		log_priority;
int		no_daemon;
int		unknown_ok = 1;
int		routefd;

struct interface_info	*ifi = NULL;

void		 usage(void);
int		 check_option(struct client_lease *l, int option);
int		 ipv4addrs(char * buf);
int		 res_hnok(const char *dn);
char		*option_as_string(unsigned int code, unsigned char *data, int len);
int		 fork_privchld(int, int);
int              check_arp( struct interface_info *ip, struct client_lease *lp );

#define	ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))

time_t	scripttime;

/* XXX Added this since it's not in the NDK ;0/ */
ULONG
NTAPI
RtlRandom(
  IN OUT PULONG  Seed
  );

/* XXX Implement me */
int check_arp( struct interface_info *ip, struct client_lease *lp ) {
    return 1;
}

static VOID CALLBACK
DispatchMain(DWORD argc, LPTSTR *argv)
{
	dispatch();
}

static SERVICE_TABLE_ENTRY ServiceTable[2] =
{
    {TEXT("DHCP"), DispatchMain},
    {NULL, NULL}
};

int
main(int argc, char *argv[])
{
    int i = 0;
        ApiInit();
        AdapterInit();
        PipeInit();

	tzset();
	time(&cur_time);

	memset(&sockaddr_broadcast, 0, sizeof(sockaddr_broadcast));
	sockaddr_broadcast.sin_family = AF_INET;
	sockaddr_broadcast.sin_port = htons(REMOTE_PORT);
	sockaddr_broadcast.sin_addr.s_addr = INADDR_BROADCAST;
	inaddr_any.s_addr = INADDR_ANY;

        DH_DbgPrint(MID_TRACE,("DHCP Service Started\n"));

	read_client_conf();

	if (!interface_link_status(ifi->name)) {
            DH_DbgPrint(MID_TRACE,("%s: no link ", ifi->name));
            Sleep(1000);
            while (!interface_link_status(ifi->name)) {
                DH_DbgPrint(MID_TRACE,("."));
                if (++i > 10) {
                    DH_DbgPrint(MID_TRACE,("Giving up for now on adapter [%s]\n", ifi->name));
                }
                Sleep(1000);
            }
            DH_DbgPrint(MID_TRACE,("Got link on [%s]\n", ifi->name));
	}

        DH_DbgPrint(MID_TRACE,("Discover Interfaces\n"));

        /* If no adapters were found, just idle for now ... If any show up,
         * then we'll start it later */
        if( ifi ) {
            /* set up the interface */
            discover_interfaces(ifi);

            DH_DbgPrint
                (MID_TRACE,
                 ("Setting init state and restarting interface %p\n",ifi));
        }

	bootp_packet_handler = do_packet;

        DH_DbgPrint(MID_TRACE,("Going into dispatch()\n"));

	StartServiceCtrlDispatcher(ServiceTable);

	/* not reached */
	return (0);
}

void
usage(void)
{
//	extern char	*__progname;

//	fprintf(stderr, "usage: %s [-dqu] ", __progname);
	fprintf(stderr, "usage: dhclient [-dqu] ");
	fprintf(stderr, "[-c conffile] [-l leasefile] interface\n");
	exit(1);
}

/*
 * Individual States:
 *
 * Each routine is called from the dhclient_state_machine() in one of
 * these conditions:
 * -> entering INIT state
 * -> recvpacket_flag == 0: timeout in this state
 * -> otherwise: received a packet in this state
 *
 * Return conditions as handled by dhclient_state_machine():
 * Returns 1, sendpacket_flag = 1: send packet, reset timer.
 * Returns 1, sendpacket_flag = 0: just reset the timer (wait for a milestone).
 * Returns 0: finish the nap which was interrupted for no good reason.
 *
 * Several per-interface variables are used to keep track of the process:
 *   active_lease: the lease that is being used on the interface
 *                 (null pointer if not configured yet).
 *   offered_leases: leases corresponding to DHCPOFFER messages that have
 *                   been sent to us by DHCP servers.
 *   acked_leases: leases corresponding to DHCPACK messages that have been
 *                 sent to us by DHCP servers.
 *   sendpacket: DHCP packet we're trying to send.
 *   destination: IP address to send sendpacket to
 * In addition, there are several relevant per-lease variables.
 *   T1_expiry, T2_expiry, lease_expiry: lease milestones
 * In the active lease, these control the process of renewing the lease;
 * In leases on the acked_leases list, this simply determines when we
 * can no longer legitimately use the lease.
 */

void
state_reboot(void *ipp)
{
	struct interface_info *ip = ipp;
	ULONG foo = (ULONG) GetTickCount();

	/* If we don't remember an active lease, go straight to INIT. */
	if (!ip->client->active || ip->client->active->is_bootp) {
		state_init(ip);
		return;
	}

	/* We are in the rebooting state. */
	ip->client->state = S_REBOOTING;

	/* make_request doesn't initialize xid because it normally comes
	   from the DHCPDISCOVER, but we haven't sent a DHCPDISCOVER,
	   so pick an xid now. */
	ip->client->xid = RtlRandom(&foo);

	/* Make a DHCPREQUEST packet, and set appropriate per-interface
	   flags. */
	make_request(ip, ip->client->active);
	ip->client->destination = iaddr_broadcast;
	ip->client->first_sending = cur_time;
	ip->client->interval = ip->client->config->initial_interval;

	/* Zap the medium list... */
	ip->client->medium = NULL;

	/* Send out the first DHCPREQUEST packet. */
	send_request(ip);
}

/*
 * Called when a lease has completely expired and we've
 * been unable to renew it.
 */
void
state_init(void *ipp)
{
	struct interface_info *ip = ipp;

	ASSERT_STATE(state, S_INIT);

	/* Make a DHCPDISCOVER packet, and set appropriate per-interface
	   flags. */
	make_discover(ip, ip->client->active);
	ip->client->xid = ip->client->packet.xid;
	ip->client->destination = iaddr_broadcast;
	ip->client->state = S_SELECTING;
	ip->client->first_sending = cur_time;
	ip->client->interval = ip->client->config->initial_interval;

	/* Add an immediate timeout to cause the first DHCPDISCOVER packet
	   to go out. */
	send_discover(ip);
}

/*
 * state_selecting is called when one or more DHCPOFFER packets
 * have been received and a configurable period of time has passed.
 */
void
state_selecting(void *ipp)
{
	struct interface_info *ip = ipp;
	struct client_lease *lp, *next, *picked;

	ASSERT_STATE(state, S_SELECTING);

	/* Cancel state_selecting and send_discover timeouts, since either
	   one could have got us here. */
	cancel_timeout(state_selecting, ip);
	cancel_timeout(send_discover, ip);

	/* We have received one or more DHCPOFFER packets.   Currently,
	   the only criterion by which we judge leases is whether or
	   not we get a response when we arp for them. */
	picked = NULL;
	for (lp = ip->client->offered_leases; lp; lp = next) {
		next = lp->next;

		/* Check to see if we got an ARPREPLY for the address
		   in this particular lease. */
		if (!picked) {
                    if( !check_arp(ip,lp) ) goto freeit;
                    picked = lp;
                    picked->next = NULL;
		} else {
freeit:
			free_client_lease(lp);
		}
	}
	ip->client->offered_leases = NULL;

	/* If we just tossed all the leases we were offered, go back
	   to square one. */
	if (!picked) {
		ip->client->state = S_INIT;
		state_init(ip);
		return;
	}

	/* If it was a BOOTREPLY, we can just take the address right now. */
	if (!picked->options[DHO_DHCP_MESSAGE_TYPE].len) {
		ip->client->new = picked;

		/* Make up some lease expiry times
		   XXX these should be configurable. */
		ip->client->new->expiry = cur_time + 12000;
		ip->client->new->renewal += cur_time + 8000;
		ip->client->new->rebind += cur_time + 10000;

		ip->client->state = S_REQUESTING;

		/* Bind to the address we received. */
		bind_lease(ip);
		return;
	}

	/* Go to the REQUESTING state. */
	ip->client->destination = iaddr_broadcast;
	ip->client->state = S_REQUESTING;
	ip->client->first_sending = cur_time;
	ip->client->interval = ip->client->config->initial_interval;

	/* Make a DHCPREQUEST packet from the lease we picked. */
	make_request(ip, picked);
	ip->client->xid = ip->client->packet.xid;

	/* Toss the lease we picked - we'll get it back in a DHCPACK. */
	free_client_lease(picked);

	/* Add an immediate timeout to send the first DHCPREQUEST packet. */
	send_request(ip);
}

/* state_requesting is called when we receive a DHCPACK message after
   having sent out one or more DHCPREQUEST packets. */

void
dhcpack(struct packet *packet)
{
	struct interface_info *ip = packet->interface;
	struct client_lease *lease;

	/* If we're not receptive to an offer right now, or if the offer
	   has an unrecognizable transaction id, then just drop it. */
	if (packet->interface->client->xid != packet->raw->xid ||
	    (packet->interface->hw_address.hlen != packet->raw->hlen) ||
	    (memcmp(packet->interface->hw_address.haddr,
	    packet->raw->chaddr, packet->raw->hlen)))
		return;

	if (ip->client->state != S_REBOOTING &&
	    ip->client->state != S_REQUESTING &&
	    ip->client->state != S_RENEWING &&
	    ip->client->state != S_REBINDING)
		return;

	note("DHCPACK from %s", piaddr(packet->client_addr));

	lease = packet_to_lease(packet);
	if (!lease) {
		note("packet_to_lease failed.");
		return;
	}

	ip->client->new = lease;

	/* Stop resending DHCPREQUEST. */
	cancel_timeout(send_request, ip);

	/* Figure out the lease time. */
	if (ip->client->new->options[DHO_DHCP_LEASE_TIME].data)
		ip->client->new->expiry = getULong(
		    ip->client->new->options[DHO_DHCP_LEASE_TIME].data);
	else
		ip->client->new->expiry = default_lease_time;
	/* A number that looks negative here is really just very large,
	   because the lease expiry offset is unsigned. */
	if (ip->client->new->expiry < 0)
		ip->client->new->expiry = TIME_MAX;