dhcpdiscover.c | searchcode

/packages/dhcpdiscover/src/dhcpdiscover.c

https://gitlab.com/libre-mesh/lime-packages
C | 1368 lines | 926 code | 298 blank | 144 comment | 141 complexity | c09d3aec13f8c643bc6e89c808a48adf MD5 | raw file

/******************************************************************************
*
* Original name: CHECK_DHCP.C
* Current name: DHCPDISCOVER.C
*
* License: GPL
* Copyright (c) 2001-2004 Ethan Galstad (nagios@nagios.org)
* Copyright (c) 2006-2013 OpenWRT.org
*
* License Information:
*
* 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.
*
*****************************************************************************/

const char *COPYRIGHT= " \
*\n \
* License: GPL\n \
* Copyright (c) 2001-2004 Ethan Galstad (nagios@nagios.org)\n \
* Copyright (c) 2006-2013 OpenWRT.org \n \
* ====================================================== \n \
* Mike Gore 25 Aug 2005 \n \
*    Modified for standalone operation \n \
* ====================================================== \n \
* Pau Escrich Jun 2013 \n \
*    Added -b option and ported to OpenWRT \n \
* ====================================================== \n \
*\n \
** License Information:\n \
*\n \
* This program is free software; you can redistribute it and/or modify\n \
* it under the terms of the GNU General Public License as published by\n \
* the Free Software Foundation; either version 2 of the License, or\n \
* (at your option) any later version.\n \
*\n \
* This program is distributed in the hope that it will be useful,\n \
* but WITHOUT ANY WARRANTY; without even the implied warranty of\n \
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n \
* GNU General Public License for more details.\n \
*\n \
* You should have received a copy of the GNU General Public License\n \
* along with this program; if not, write to the Free Software\n \
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.\n \
*\n \
* $Id: dhcpdiscover.c,v 2$\n \
*"; 

const char *progname = "dhcpdiscover";
const char *revision = "$Revision: 2$";
const char *copyright = "2006-2013";
const char *email = "p4u@dabax.net";

#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netdb.h>
#include <netinet/in.h>
#include <net/if.h>
#include <arpa/inet.h>

#if defined( __linux__ )

#include <linux/if_ether.h>
#include <features.h>

#elif defined (__bsd__)

#include <netinet/if_ether.h>
#include <sys/sysctl.h>
#include <net/if_dl.h>

#elif defined(__sun__) || defined(__solaris__) || defined(__hpux__)

#define INSAP 22 
#define OUTSAP 24 

#include <signal.h>
#include <ctype.h>
#include <sys/stropts.h>
#include <sys/poll.h>
#include <sys/dlpi.h>

#define bcopy(source, destination, length) memcpy(destination, source, length)

#define AREA_SZ 5000		/* buffer length in bytes */ 
static u_long ctl_area[AREA_SZ];
static u_long dat_area[AREA_SZ];
static struct strbuf ctl = {AREA_SZ, 0, (char *)ctl_area};
static struct strbuf dat = {AREA_SZ, 0, (char *)dat_area};

#define GOT_CTRL 1 
#define GOT_DATA 2 
#define GOT_BOTH 3 
#define GOT_INTR 4 
#define GOT_ERR 128 

#define u_int8_t	 uint8_t
#define u_int16_t	uint16_t
#define u_int32_t	uint32_t

static int get_msg(int);
static int check_ctrl(int);
static int put_ctrl(int, int, int);
static int put_both(int, int, int, int);
static int dl_open(const char *, int, int *);
static int dl_bind(int, int, u_char *);
long mac_addr_dlpi( const char *, int, u_char *);

#endif

#define HAVE_GETOPT_H

#define usage printf

/**** Common definitions ****/

#define STATE_OK          0
#define STATE_WARNING     1
#define STATE_CRITICAL    2
#define STATE_UNKNOWN     -1

#define OK                0
#define ERROR             -1

#define FALSE             0
#define TRUE              1


/**** DHCP definitions ****/

#define MAX_DHCP_CHADDR_LENGTH           16
#define MAX_DHCP_SNAME_LENGTH            64
#define MAX_DHCP_FILE_LENGTH             128
#define MAX_DHCP_OPTIONS_LENGTH          312


typedef struct dhcp_packet_struct{
        u_int8_t  op;                   /* packet type */
        u_int8_t  htype;                /* type of hardware address for this machine (Ethernet, etc) */
        u_int8_t  hlen;                 /* length of hardware address (of this machine) */
        u_int8_t  hops;                 /* hops */
        u_int32_t xid;                  /* random transaction id number - chosen by this machine */
        u_int16_t secs;                 /* seconds used in timing */
        u_int16_t flags;                /* flags */
        struct in_addr ciaddr;          /* IP address of this machine (if we already have one) */
        struct in_addr yiaddr;          /* IP address of this machine (offered by the DHCP server) */
        struct in_addr siaddr;          /* IP address of DHCP server */
        struct in_addr giaddr;          /* IP address of DHCP relay */
        unsigned char chaddr [MAX_DHCP_CHADDR_LENGTH];      /* hardware address of this machine */
        char sname [MAX_DHCP_SNAME_LENGTH];    /* name of DHCP server */
        char file [MAX_DHCP_FILE_LENGTH];      /* boot file name (used for diskless booting?) */
	char options[MAX_DHCP_OPTIONS_LENGTH];  /* options */
        }dhcp_packet;


typedef struct dhcp_offer_struct{
	struct in_addr server_address;   /* address of DHCP server that sent this offer */
	struct in_addr offered_address;  /* the IP address that was offered to us */
	u_int32_t lease_time;            /* lease time in seconds */
	u_int32_t renewal_time;          /* renewal time in seconds */
	u_int32_t rebinding_time;        /* rebinding time in seconds */
	struct dhcp_offer_struct *next;
        }dhcp_offer;


typedef struct requested_server_struct{
	struct in_addr server_address;
	struct requested_server_struct *next;
        }requested_server;


#define BOOTREQUEST     1
#define BOOTREPLY       2

#define DHCPDISCOVER    1
#define DHCPOFFER       2
#define DHCPREQUEST     3
#define DHCPDECLINE     4
#define DHCPACK         5
#define DHCPNACK        6
#define DHCPRELEASE     7

#define DHCP_OPTION_MESSAGE_TYPE        53
#define DHCP_OPTION_HOST_NAME           12
#define DHCP_OPTION_BROADCAST_ADDRESS   28
#define DHCP_OPTION_REQUESTED_ADDRESS   50
#define DHCP_OPTION_LEASE_TIME          51
#define DHCP_OPTION_RENEWAL_TIME        58
#define DHCP_OPTION_REBINDING_TIME      59

#define DHCP_INFINITE_TIME              0xFFFFFFFF

#define DHCP_BROADCAST_FLAG 32768

#define DHCP_SERVER_PORT   67
#define DHCP_CLIENT_PORT   68

#define ETHERNET_HARDWARE_ADDRESS            1     /* used in htype field of dhcp packet */
#define ETHERNET_HARDWARE_ADDRESS_LENGTH     6     /* length of Ethernet hardware addresses */

unsigned char client_hardware_address[MAX_DHCP_CHADDR_LENGTH]="";
unsigned int my_client_mac[MAX_DHCP_CHADDR_LENGTH];
int mymac = 0;

struct in_addr banned_ip;
int banned = 0;
char baddr[16];

char network_interface_name[8]="eth0";

u_int32_t packet_xid=0;

u_int32_t dhcp_lease_time=0;
u_int32_t dhcp_renewal_time=0;
u_int32_t dhcp_rebinding_time=0;

int dhcpoffer_timeout=2;

dhcp_offer *dhcp_offer_list=NULL;
requested_server *requested_server_list=NULL;

int valid_responses=0;     /* number of valid DHCPOFFERs we received */
int requested_servers=0;   
int requested_responses=0;

int request_specific_address=FALSE;
int received_requested_address=FALSE;
int verbose=0;
struct in_addr requested_address;

void print_revision(const char *progname,const char *revision)
{
	printf("Program: %s %s\n",progname,revision);
}


int process_arguments(int, char **);
int call_getopt(int, char **);
int validate_arguments(void);
void print_usage(void);
void print_help(void);

int get_hardware_address(int,char *);

int send_dhcp_discover(int);
int get_dhcp_offer(int);

int get_results(void);

int add_dhcp_offer(struct in_addr,dhcp_packet *);
int free_dhcp_offer_list(void);
int free_requested_server_list(void);

int create_dhcp_socket(void);
int close_dhcp_socket(int);
int send_dhcp_packet(void *,int,int,struct sockaddr_in *);
int receive_dhcp_packet(void *,int,int,int,struct sockaddr_in *);



int main(int argc, char **argv){
	int dhcp_socket;
	int result;

	setlocale (LC_ALL, "");
	// bindtextdomain (PACKAGE, LOCALEDIR);
	// textdomain (PACKAGE);
	
	if(process_arguments(argc,argv)!=OK){
		printf("Could not parse arguments");
		}
		
	// Set banned addr in string format in global var baddr
	if ( banned ) {
		inet_ntop(AF_INET, &(banned_ip), baddr, INET_ADDRSTRLEN);
		if(verbose) printf("Banned addr:%s\n",baddr);
		}

	/* create socket for DHCP communications */
	dhcp_socket=create_dhcp_socket();

	/* get hardware address of client machine */
	get_hardware_address(dhcp_socket,network_interface_name);

	/* send DHCPDISCOVER packet */
	send_dhcp_discover(dhcp_socket);

	/* wait for a DHCPOFFER packet */
	get_dhcp_offer(dhcp_socket);

	/* close socket we created */
	close_dhcp_socket(dhcp_socket);

	/* determine state/plugin output to return */
	result=get_results();

	/* free allocated memory */
	free_dhcp_offer_list();
	free_requested_server_list();

	return result;
        }



/* determines hardware address on client machine */
int get_hardware_address(int sock,char *interface_name){

	int i;

#if defined(__linux__)
	struct ifreq ifr;

	strncpy((char *)&ifr.ifr_name,interface_name,sizeof(ifr.ifr_name));
	
	// Added code to try to set local MAC address just to be through
	// If this fails the test will still work since
	// we do encode the MAC as part of the DHCP frame - tests show it works
	if(mymac)
	{ 
		int i;
		for(i=0;i<MAX_DHCP_CHADDR_LENGTH;++i)
			client_hardware_address[i] = my_client_mac[i];
		memcpy(&ifr.ifr_hwaddr.sa_data,&client_hardware_address[0],6);
		if(ioctl(sock,SIOCSIFHWADDR,&ifr)<0){
			printf("Error: Could not set hardware address of interface '%s'\n",interface_name);
			// perror("Error");
			// exit(STATE_UNKNOWN);
	        }


	}
	else
	{
		/* try and grab hardware address of requested interface */
		if(ioctl(sock,SIOCGIFHWADDR,&ifr)<0){
			printf("Error: Could not get hardware address of interface '%s'\n",interface_name);
			exit(STATE_UNKNOWN);
	        }
		memcpy(&client_hardware_address[0],&ifr.ifr_hwaddr.sa_data,6);
	}

#elif defined(__bsd__)
						/* King 2004	see ACKNOWLEDGEMENTS */

        int                     mib[6], len;
        char                    *buf;
        unsigned char           *ptr;
        struct if_msghdr        *ifm;
        struct sockaddr_dl      *sdl;

        mib[0] = CTL_NET;
        mib[1] = AF_ROUTE;
        mib[2] = 0;
        mib[3] = AF_LINK;
        mib[4] = NET_RT_IFLIST;

        if ((mib[5] = if_nametoindex(interface_name)) == 0) {
                printf("Error: if_nametoindex error - %s.\n", strerror(errno);
                exit(STATE_UNKNOWN);
        }

        if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {
                printf("Error: Couldn't get hardware address from %s. sysctl 1 error - %s.\n", interface_name, strerror(errno);
                exit(STATE_UNKNOWN);
        }

        if ((buf = malloc(len)) == NULL) {
                printf("Error: Couldn't get hardware address from interface %s. malloc error - %s.\n", interface_name, strerror(errno);
                exit(4);
        }

        if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
                printf("Error: Couldn't get hardware address from %s. sysctl 2 error - %s.\n", interface_name, strerror(errno);
                exit(STATE_UNKNOWN);
        }

        ifm = (struct if_msghdr *)buf;
        sdl = (struct sockaddr_dl *)(ifm + 1);
        ptr = (unsigned char *)LLADDR(sdl);
	memcpy(&client_hardware_address[0], ptr, 6) ;
						/* King 2004 */

#elif defined(__sun__) || defined(__solaris__)

						/* Kompf 2000-2003	see ACKNOWLEDGEMENTS */
	long stat;
	char dev[20] = "/dev/";
	char *p;
	int unit;

	for (p = interface_name; *p && isalpha(*p); p++)
		/* no-op */ ;
	if ( p != '\0' ) {
		unit = atoi(p) ;
		*p = '\0' ;
		strncat(dev, interface_name, 6) ;
	} else {
		printf("Error: can't find unit number in interface_name (%s) - expecting TypeNumber eg lnc0.\n", interface_name);
		exit(STATE_UNKNOWN);
	}
	stat = mac_addr_dlpi(dev, unit, client_hardware_address);
	if (stat != 0) {
		printf("Error: can't read MAC address from DLPI streams interface for device %s unit %d.\n", dev, unit);
		exit(STATE_UNKNOWN);
	}

#elif defined(__hpux__)

	long stat;
	char dev[20] = "/dev/dlpi" ;
	int unit = 0;

	stat = mac_addr_dlpi(dev, unit, client_hardware_address);
	if (stat != 0) {
		printf("Error: can't read MAC address from DLPI streams interface for device %s unit %d.\n", dev, unit);
		exit(STATE_UNKNOWN);
	}
						/* Kompf 2000-2003 */

#else
	printf("Error: can't get MAC address for this architecture.\n");
	exit(STATE_UNKNOWN);
#endif

	if (verbose) { 
		printf("Hardware address: ");
		for (i=0; i<6; ++i)
			printf("%2.2x", client_hardware_address[i]);
		printf( "\n");
	}

	return OK;
        }


/* sends a DHCPDISCOVER broadcast message in an attempt to find DHCP servers */
int send_dhcp_discover(int sock){
	dhcp_packet discover_packet;
	struct sockaddr_in sockaddr_broadcast;


	/* clear the packet data structure */
	bzero(&discover_packet,sizeof(discover_packet));


	/* boot request flag (backward compatible with BOOTP servers) */
	discover_packet.op=BOOTREQUEST;

	/* hardware address type */
	discover_packet.htype=ETHERNET_HARDWARE_ADDRESS;

	/* length of our hardware address */
	discover_packet.hlen=ETHERNET_HARDWARE_ADDRESS_LENGTH;

	discover_packet.hops=0;

	/* transaction id is supposed to be random */
	srand(time(NULL));
	packet_xid=random();
	discover_packet.xid=htonl(packet_xid);

	/**** WHAT THE HECK IS UP WITH THIS?!?  IF I DON'T MAKE THIS CALL, ONLY ONE SERVER RESPONSE IS PROCESSED!!!! ****/
	/* downright bizzarre... */
	ntohl(discover_packet.xid);

	/*discover_packet.secs=htons(65535);*/
	discover_packet.secs=0xFF;

	/* tell server it should broadcast its response */ 
	discover_packet.flags=htons(DHCP_BROADCAST_FLAG);

	/* our hardware address */
	memcpy(discover_packet.chaddr,client_hardware_address,ETHERNET_HARDWARE_ADDRESS_LENGTH);

	/* first four bytes of options field is magic cookie (as per RFC 2132) */
	discover_packet.options[0]='\x63';
	discover_packet.options[1]='\x82';
	discover_packet.options[2]='\x53';
	discover_packet.options[3]='\x63';

	/* DHCP message type is embedded in options field */
	discover_packet.options[4]=DHCP_OPTION_MESSAGE_TYPE;    /* DHCP message type option identifier */
	discover_packet.options[5]='\x01';               /* DHCP message option length in bytes */
	discover_packet.options[6]=DHCPDISCOVER;

	/* the IP address we're requesting */
	if(request_specific_address==TRUE){
		discover_packet.options[7]=DHCP_OPTION_REQUESTED_ADDRESS;
		discover_packet.options[8]='\x04';
		memcpy(&discover_packet.options[9],&requested_address,sizeof(requested_address));
	        }
	
	/* send the DHCPDISCOVER packet to broadcast address */
        sockaddr_broadcast.sin_family=AF_INET;
        sockaddr_broadcast.sin_port=htons(DHCP_SERVER_PORT);
        sockaddr_broadcast.sin_addr.s_addr=INADDR_BROADCAST;
	bzero(&sockaddr_broadcast.sin_zero,sizeof(sockaddr_broadcast.sin_zero));


	if (verbose) {
		printf("DHCPDISCOVER to %s port %d\n",inet_ntoa(sockaddr_broadcast.sin_addr),ntohs(sockaddr_broadcast.sin_port));
		printf("DHCPDISCOVER XID: %lu (0x%X)\n",(unsigned long) ntohl(discover_packet.xid),ntohl(discover_packet.xid));
		printf("DHCDISCOVER ciaddr:  %s\n",inet_ntoa(discover_packet.ciaddr));
		printf("DHCDISCOVER yiaddr:  %s\n",inet_ntoa(discover_packet.yiaddr));
		printf("DHCDISCOVER siaddr:  %s\n",inet_ntoa(discover_packet.siaddr));
		printf("DHCDISCOVER giaddr:  %s\n",inet_ntoa(discover_packet.giaddr));
	}

	/* send the DHCPDISCOVER packet out */
	send_dhcp_packet(&discover_packet,sizeof(discover_packet),sock,&sockaddr_broadcast);

	if (verbose) 
		printf("\n\n");

	return OK;
        }




/* waits for a DHCPOFFER message from one or more DHCP servers */
int get_dhcp_offer(int sock){
	dhcp_packet offer_packet;
	struct sockaddr_in source;
	int result=OK;
	int timeout=1;
	int responses=0;
	int x;
	time_t start_time;
	time_t current_time;

	time(&start_time);

	/* receive as many responses as we can */
	for(responses=0,valid_responses=0;;){

		time(&current_time);
		if((current_time-start_time)>=dhcpoffer_timeout)
			break;

		if (verbose) 
			printf("\n\n");

		bzero(&source,sizeof(source));
		bzero(&offer_packet,sizeof(offer_packet));

		result=OK;
		result=receive_dhcp_packet(&offer_packet,sizeof(offer_packet),sock,dhcpoffer_timeout,&source);
		
		// checks if the source address is the banned one
	    char saddr[16];
	    inet_ntop(AF_INET, &(source.sin_addr), saddr, INET_ADDRSTRLEN);
	    
	    if (banned && strcmp(saddr,baddr) == 0) {
		    printf("DHCP offer comming from the banned addr %s, ignoring it\n",baddr);
		    result = 1;
	    }


		
		if(result!=OK){
			if (verbose)
				printf("Result=ERROR\n");

			continue;
		        }
		else{
			if (verbose) 
				printf("Result=OK\n");

			responses++;
		        }

		if (verbose) {
			printf("DHCPOFFER from IP address %s\n",inet_ntoa(source.sin_addr));
			printf("DHCPOFFER XID: %lu (0x%X)\n",(unsigned long) ntohl(offer_packet.xid),ntohl(offer_packet.xid));
		}

		/* check packet xid to see if its the same as the one we used in the discover packet */
		if(ntohl(offer_packet.xid)!=packet_xid){
			if (verbose)
				printf("DHCPOFFER XID (%lu) did not match DHCPDISCOVER XID (%lu) - ignoring packet\n",(unsigned long) ntohl(offer_packet.xid),(unsigned long) packet_xid);

			continue;
		        }

		/* check hardware address */
		result=OK;
		if (verbose)
			printf("DHCPOFFER chaddr: ");

		for(x=0;x<ETHERNET_HARDWARE_ADDRESS_LENGTH;x++){
			if (verbose)
				printf("%02X",(unsigned char)offer_packet.chaddr[x]);

			if(offer_packet.chaddr[x]!=client_hardware_address[x])
				result=ERROR;
		}
		if (verbose)
			printf("\n");

		if(result==ERROR){
			if (verbose) 
				printf("DHCPOFFER hardware address did not match our own - ignoring packet\n");

			continue;
		        }

		if (verbose) {
			printf("DHCPOFFER ciaddr: %s\n",inet_ntoa(offer_packet.ciaddr));
			printf("DHCPOFFER yiaddr: %s\n",inet_ntoa(offer_packet.yiaddr));
			printf("DHCPOFFER siaddr: %s\n",inet_ntoa(offer_packet.siaddr));
			printf("DHCPOFFER giaddr: %s\n",inet_ntoa(offer_packet.giaddr));
		}

		add_dhcp_offer(source.sin_addr,&offer_packet);

		valid_responses++;
	        }

	if (verbose) {
		printf("Total responses seen on the wire: %d\n",responses);
		printf("Valid responses for this machine: %d\n",valid_responses);
	}

	return OK;
        }



/* sends a DHCP packet */
int send_dhcp_packet(void *buffer, int buffer_size, int sock, struct sockaddr_in *dest){
	struct sockaddr_in myname;
	int result;

	result=sendto(sock,(char *)buffer,buffer_size,0,(struct sockaddr *)dest,sizeof(*dest));

	if (verbose) 
		printf("send_dhcp_packet result: %d\n",result);

	if(result<0)
		return ERROR;

	return OK;
        }



/* receives a DHCP packet */
int receive_dhcp_packet(void *buffer, int buffer_size, int sock, int timeout, struct sockaddr_in *address){
    struct timeval tv;
    fd_set readfds;
	int recv_result;
	unsigned long srcmac;
	socklen_t address_size;
	struct sockaddr_in source_address;

        /* wait for data to arrive (up time timeout) */
        tv.tv_sec=timeout;
        tv.tv_usec=0;
        FD_ZERO(&readfds);
        FD_SET(sock,&readfds);
        select(sock+1,&readfds,NULL,NULL,&tv);

        /* make sure some data has arrived */
        if(!FD_ISSET(sock,&readfds)){
		if (verbose)
                	printf("No (more) data received\n");
                return ERROR;
                }

        else{

		/* why do we need to peek first?  i don't know, its a hack.  without it, the source address of the first packet received was
		   not being interpreted correctly.  sigh... */
		bzero(&source_address,sizeof(source_address));
		address_size=sizeof(source_address);
        recv_result=recvfrom(sock,(char *)buffer,buffer_size,MSG_PEEK,(struct sockaddr *)&source_address,&address_size);
		
		if (verbose)
			printf("recv_result_1: %d\n",recv_result);
                recv_result=recvfrom(sock,(char *)buffer,buffer_size,0,(struct sockaddr *)&source_address,&address_size);
		if (verbose)
			printf("recv_result_2: %d\n",recv_result);

                if(recv_result==-1){
			if (verbose) {
				printf("recvfrom() failed, ");
				printf("errno: (%d) -> %s\n",errno,strerror(errno));
			}
                        return ERROR;
                        }
		else{
			if (verbose) {
				printf("receive_dhcp_packet() result: %d\n",recv_result);
				printf("receive_dhcp_packet() source: %s\n",inet_ntoa(source_address.sin_addr));
			}

			memcpy(address,&source_address,sizeof(source_address));
			return OK;
		        }
                }

	return OK;
        }


/* creates a socket for DHCP communication */
int create_dhcp_socket(void){
    struct sockaddr_in myname;
	struct ifreq interface;
        int sock;
        int flag=1;

        /* Set up the address we're going to bind to. */
	bzero(&myname,sizeof(myname));
        myname.sin_family=AF_INET;
        myname.sin_port=htons(DHCP_CLIENT_PORT);
        myname.sin_addr.s_addr=INADDR_ANY;                 /* listen on any address */
        bzero(&myname.sin_zero,sizeof(myname.sin_zero));

        /* create a socket for DHCP communications */
	sock=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
        if(sock<0){
		printf("Error: Could not create socket!\n");
		exit(STATE_UNKNOWN);
	        }

	if (verbose)
		printf("DHCP socket: %d\n",sock);

        /* set the reuse address flag so we don't get errors when restarting */
        flag=1;
        if(setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(char *)&flag,sizeof(flag))<0){
		printf("Error: Could not set reuse address option on DHCP socket!\n");
		exit(STATE_UNKNOWN);
	        }

        /* set the broadcast option - we need this to listen to DHCP broadcast messages */
        if(setsockopt(sock,SOL_SOCKET,SO_BROADCAST,(char *)&flag,sizeof flag)<0){
		printf("Error: Could not set broadcast option on DHCP socket!\n");
		exit(STATE_UNKNOWN);
	        }

	/* bind socket to interface */
#if defined(__linux__)
	strncpy(interface.ifr_ifrn.ifrn_name,network_interface_name,IFNAMSIZ);
	if(setsockopt(sock,SOL_SOCKET,SO_BINDTODEVICE,(char *)&interface,sizeof(interface))<0){
		printf("Error: Could not bind socket to interface %s.  Check your privileges...\n",network_interface_name);
		exit(STATE_UNKNOWN);
	        }

#else
	strncpy(interface.ifr_name,network_interface_name,IFNAMSIZ);
#endif

        /* bind the socket */
        if(bind(sock,(struct sockaddr *)&myname,sizeof(myname))<0){
		printf("Error: Could not bind to DHCP socket (port %d)!  Check your privileges...\n",DHCP_CLIENT_PORT);
		exit(STATE_UNKNOWN);
	        }

        return sock;
        }


/* closes DHCP socket */
int close_dhcp_socket(int sock){

	close(sock);

	return OK;
        }


/* adds a requested server address to list in memory */
int add_requested_server(struct in_addr server_address){
	requested_server *new_server;

	new_server=(requested_server *)malloc(sizeof(requested_server));
	if(new_server==NULL)
		return ERROR;

	new_server->server_address=server_address;

	new_server->next=requested_server_list;
	requested_server_list=new_server;

	requested_servers++;

	if (verbose)
		printf("Requested server address: %s\n",inet_ntoa(new_server->server_address));

	return OK;
        }




/* adds a DHCP OFFER to list in memory */
int add_dhcp_offer(struct in_addr source,dhcp_packet *offer_packet){
	dhcp_offer *new_offer;
	int x;
	int y;
	unsigned option_type;
	unsigned option_length;

	if(offer_packet==NULL)
		return ERROR;

	/* process all DHCP options present in the packet */
	for(x=4;x<MAX_DHCP_OPTIONS_LENGTH;){

		/* end of options (0 is really just a pad, but bail out anyway) */
		if((int)offer_packet->options[x]==-1 || (int)offer_packet->options[x]==0)
			break;

		/* get option type */
		option_type=offer_packet->options[x++];

		/* get option length */
		option_length=offer_packet->options[x++];

		if (verbose) 
			printf("Option: %d (0x%02X)\n",option_type,option_length);

		/* get option data */
        if(option_type==DHCP_OPTION_LEASE_TIME) {
            memcpy(&dhcp_lease_time, &offer_packet->options[x],
                sizeof(dhcp_lease_time));
            dhcp_lease_time = ntohl(dhcp_lease_time);
        }
        if(option_type==DHCP_OPTION_RENEWAL_TIME) {
            memcpy(&dhcp_renewal_time, &offer_packet->options[x],
                sizeof(dhcp_renewal_time));
            dhcp_renewal_time = ntohl(dhcp_renewal_time);
        }
        if(option_type==DHCP_OPTION_REBINDING_TIME) {
            memcpy(&dhcp_rebinding_time, &offer_packet->options[x],
                sizeof(dhcp_rebinding_time));
            dhcp_rebinding_time = ntohl(dhcp_rebinding_time);
        }

		/* skip option data we're ignoring */
		else
			for(y=0;y<option_length;y++,x++);
	        }

	if (verbose) {
		if(dhcp_lease_time==DHCP_INFINITE_TIME)
			printf("Lease Time: Infinite\n");
		else
			printf("Lease Time: %lu seconds\n",(unsigned long)dhcp_lease_time);
		if(dhcp_renewal_time==DHCP_INFINITE_TIME)
			printf("Renewal Time: Infinite\n");
		else
			printf("Renewal Time: %lu seconds\n",(unsigned long)dhcp_renewal_time);
		if(dhcp_rebinding_time==DHCP_INFINITE_TIME)
			printf("Rebinding Time: Infinite\n");
		printf("Rebinding Time: %lu seconds\n",(unsigned long)dhcp_rebinding_time);
	}

	new_offer=(dhcp_offer *)malloc(sizeof(dhcp_offer));

	if(new_offer==NULL)
		return ERROR;

	new_offer->server_address=source;
	new_offer->offered_address=offer_packet->yiaddr;
	new_offer->lease_time=dhcp_lease_time;
	new_offer->renewal_time=dhcp_renewal_time;
	new_offer->rebinding_time=dhcp_rebinding_time;

	if (verbose) {
		printf("Added offer from server @ %s",inet_ntoa(new_offer->server_address));
		printf(" of IP address %s\n",inet_ntoa(new_offer->offered_address));
	}

	/* add new offer to head of list */
	new_offer->next=dhcp_offer_list;
	dhcp_offer_list=new_offer;

	return OK;
        }


/* frees memory allocated to DHCP OFFER list */
int free_dhcp_offer_list(void){
	dhcp_offer *this_offer;
	dhcp_offer *next_offer;

	for(this_offer=dhcp_offer_list;this_offer!=NULL;this_offer=next_offer){
		next_offer=this_offer->next;
		free(this_offer);
	        }

	return OK;
        }


/* frees memory allocated to requested server list */
int free_requested_server_list(void){
	requested_server *this_server;
	requested_server *next_server;

	for(this_server=requested_server_list;this_server!=NULL;this_server=next_server){
		next_server=this_server->next;
		free(this_server);
	        }
	
	return OK;
        }


/* gets state and plugin output to return */
int get_results(void){
	dhcp_offer *temp_offer;
	requested_server *temp_server;
	int result;
	u_int32_t max_lease_time=0;

	received_requested_address=FALSE;

	/* checks responses from requested servers */
	requested_responses=0;
	if(requested_servers>0){

		for(temp_server=requested_server_list;temp_server!=NULL;temp_server=temp_server->next){

			for(temp_offer=dhcp_offer_list;temp_offer!=NULL;temp_offer=temp_offer->next){

				/* get max lease time we were offered */
				if(temp_offer->lease_time>max_lease_time || temp_offer->lease_time==DHCP_INFINITE_TIME)
					max_lease_time=temp_offer->lease_time;
				
				/* see if we got the address we requested */
				if(!memcmp(&requested_address,&temp_offer->offered_address,sizeof(requested_address)))
					received_requested_address=TRUE;

				/* see if the servers we wanted a response from talked to us or not */
				if(!memcmp(&temp_offer->server_address,&temp_server->server_address,sizeof(temp_server->server_address))){
	if (verbose) {
					printf("DHCP Server Match: Offerer=%s",inet_ntoa(temp_offer->server_address));
					printf(" Requested=%s\n",inet_ntoa(temp_server->server_address));
	}				       
					requested_responses++;
				        }
		                }
		        }

	        }

	/* else check and see if we got our requested address from any server */
	else{

		for(temp_offer=dhcp_offer_list;temp_offer!=NULL;temp_offer=temp_offer->next){

			/* get max lease time we were offered */
			if(temp_offer->lease_time>max_lease_time || temp_offer->lease_time==DHCP_INFINITE_TIME)
				max_lease_time=temp_offer->lease_time;
				
			/* see if we got the address we requested */
			if(!memcmp(&requested_address,&temp_offer->offered_address,sizeof(requested_address)))
				received_requested_address=TRUE;
	                }
	        }

	result=STATE_OK;
	if(valid_responses==0)
		result=STATE_CRITICAL;
	else if(requested_servers>0 && requested_responses==0)
		result=STATE_CRITICAL;
	else if(requested_responses<requested_servers)
		result=STATE_WARNING;
	else if(request_specific_address==TRUE && received_requested_address==FALSE)
		result=STATE_WARNING;


	printf("DHCP %s: ",(result==STATE_OK)?"ok":"problem");

	/* we didn't receive any DHCPOFFERs */
	if(dhcp_offer_list==NULL){
		printf("No DHCPOFFERs were received.\n");
		return result;
	        }

	printf("Received %d DHCPOFFER(s)",valid_responses);

	if(requested_servers>0)
		printf(", %s%d of %d requested servers responded",((requested_responses<requested_servers) && requested_responses>0)?"only ":"",requested_responses,requested_servers);

	if(request_specific_address==TRUE)
		printf(", requested address (%s) was %soffered",inet_ntoa(requested_address),(received_requested_address==TRUE)?"":"not ");

	printf(", max lease time = ");
	if(max_lease_time==DHCP_INFINITE_TIME)
		printf("Infinity");
	else
		printf("%lu sec",(unsigned long)max_lease_time);

	printf(".\n");

	return result;
        }


/* process command-line arguments */
int process_arguments(int argc, char **argv){
	int c;

	if(argc<1)
		return ERROR;

	c=0;
	while((c+=(call_getopt(argc-c,&argv[c])))<argc){

		/*
		if(is_option(argv[c]))
			continue;
		*/
		}

	return validate_arguments();
        }



int call_getopt(int argc, char **argv){
	int c=0;
	int i=0;
	struct in_addr ipaddress;

#ifdef HAVE_GETOPT_H
	int option_index = 0;
	int ret;
	static struct option long_options[] =
	{ 
		{"serverip",       required_argument,0,'s'},
		{"requestedip",    required_argument,0,'r'},
		{"timeout",        required_argument,0,'t'},
		{"interface",      required_argument,0,'i'},
		{"mac",      	   required_argument,0,'m'},
		{"bannedip",       required_argument,0,'b'},
		{"verbose",        no_argument,      0,'v'},
		{"version",        no_argument,      0,'V'},
		{"help",           no_argument,      0,'h'},
		{0,0,0,0}
	};
#endif

	while(1){
#ifdef HAVE_GETOPT_H
		c=getopt_long(argc,argv,"+hVvt:s:r:t:i:m:b:",long_options,&option_index);
#else
		c=getopt(argc,argv,"+?hVvt:s:r:t:i:m:b:");
#endif

		i++;

		if(c==-1||c==EOF||c==1)
			break;

		switch(c){
		case 'w':
		case 'r':
		case 't':
		case 'i':
			i++;
			break;
		default:
			break;
		        }

		switch(c){

		case 'm': /* Our MAC address */
			{
			ret = sscanf(optarg,"%x:%x:%x:%x:%x:%x", 
				my_client_mac+0,
				my_client_mac+1,
				my_client_mac+2,
				my_client_mac+3,
				my_client_mac+4,
				my_client_mac+5);
			if(ret != 6) {
				usage("Invalid MAC address\n");
				break;
			}
			for(i=0;i<6;++i) 
				client_hardware_address[i] = my_client_mac[i];
			}
			mymac = 1;
			break;
		case 'b': /* Banned IP */
			if(inet_aton(optarg,&ipaddress)) {
				banned_ip = ipaddress;
				banned = 1;
			}
			else 
				printf("Banned IP not specified, ignoring -b");
			break;
		
		case 's': /* DHCP server address */
			if(inet_aton(optarg,&ipaddress))
				add_requested_server(ipaddress);
			/*
			else
				usage("Invalid server IP address\n");
			*/
			break;

		case 'r': /* address we are requested from DHCP servers */
			if(inet_aton(optarg,&ipaddress)){
				requested_address=ipaddress;
				request_specific_address=TRUE;
			        }
			/*
			else
				usage("Invalid requested IP address\n");
			*/
			break;

		case 't': /* timeout */

			/*
			if(is_intnonneg(optarg))
			*/
			if(atoi(optarg)>0)
				dhcpoffer_timeout=atoi(optarg);
			/*
			else
				usage("Time interval must be a nonnegative integer\n");
			*/
			break;

		case 'i': /* interface name */

			strncpy(network_interface_name,optarg,sizeof(network_interface_name)-1);
			network_interface_name[sizeof(network_interface_name)-1]='\x0';

			break;

		case 'V': /* version */
			print_revision(progname,revision);
			exit(STATE_OK);

		case 'h': /* help */
			print_help();
			exit(STATE_OK);

		case 'v': /* verbose */
			verbose=1;
			break;

		default: /* help */
			printf("Unknown argument", optarg);
			break;
		        }
	        }

	return i;
        }


int validate_arguments(void){

	return OK;
        }

#if defined(__sun__) || defined(__solaris__) || defined(__hpux__)

						/* Kompf 2000-2003	see ACKNOWLEDGEMENTS */

/* get a message from a stream; return type of message */
static int get_msg(int fd)
{
    int flags = 0;
    int res, ret;
    ctl_area[0] = 0;
    dat_area[0] = 0;
    ret = 0;
    res = getmsg(fd, &ctl, &dat, &flags);

    if(res < 0) {
        if(errno == EINTR) {
            return(GOT_INTR);
        } else {
	    printf("%s\n", "get_msg FAILED.");
            return(GOT_ERR);
        }
    }
    if(ctl.len > 0) {
        ret |= GOT_CTRL;
    }
    if(dat.len > 0) {
        ret |= GOT_DATA;
    }
    return(ret);
}

/* verify that dl_primitive in ctl_area = prim */
static int check_ctrl(int prim)
{
    dl_error_ack_t *err_ack = (dl_error_ack_t *)ctl_area;
    if(err_ack->dl_primitive != prim) {
	printf("Error: DLPI stream API failed to get MAC in check_ctrl: %s.\n", strerror(errno);
        exit(STATE_UNKNOWN);
    }
    return 0;
}

/* put a control message on a stream */
static int put_ctrl(int fd, int len, int pri)
{
    ctl.len = len;
    if(putmsg(fd, &ctl, 0, pri) < 0) {
	printf("Error: DLPI stream API failed to get MAC in put_ctrl/putmsg(): %s.\n", strerror(errno);
        exit(STATE_UNKNOWN);
    }
    return  0;
}

/* put a control + data message on a stream */
static int put_both(int fd, int clen, int dlen, int pri)
{
    ctl.len = clen;
    dat.len = dlen;
    if(putmsg(fd, &ctl, &dat, pri) < 0) {
	printf("Error: DLPI stream API failed to get MAC in put_both/putmsg().\n", strerror(errno);
        exit(STATE_UNKNOWN);
    }
    return  0;
}

/* open file descriptor and attach */
static int dl_open(const char *dev, int unit, int *fd)
{
    dl_attach_req_t *attach_req = (dl_attach_req_t *)ctl_area;
    if((*fd = open(dev, O_RDWR)) == -1) {
	printf("Error: DLPI stream API failed to get MAC in dl_attach_req/open(%s..): %s.\n", dev, strerror(errno);
        exit(STATE_UNKNOWN);
    }
    attach_req->dl_primitive = DL_ATTACH_REQ;
    attach_req->dl_ppa = unit;
    put_ctrl(*fd, sizeof(dl_attach_req_t), 0);
    get_msg(*fd);
    return check_ctrl(DL_OK_ACK);
}

/* send DL_BIND_REQ */
static int dl_bind(int fd, int sap, u_char *addr)
{
    dl_bind_req_t *bind_req = (dl_bind_req_t *)ctl_area;
    dl_bind_ack_t *bind_ack = (dl_bind_ack_t *)ctl_area;
    bind_req->dl_primitive = DL_BIND_REQ;
    bind_req->dl_sap = sap;
    bind_req->dl_max_conind = 1;
    bind_req->dl_service_mode = DL_CLDLS;
    bind_req->dl_conn_mgmt = 0;
    bind_req->dl_xidtest_flg = 0;
    put_ctrl(fd, sizeof(dl_bind_req_t), 0);
    get_msg(fd);
    if (GOT_ERR == check_ctrl(DL_BIND_ACK)) {
	printf("Error: DLPI stream API failed to get MAC in dl_bind/check_ctrl(): %s.\n", strerror(errno);
        exit(STATE_UNKNOWN);
    }
    bcopy((u_char *)bind_ack + bind_ack->dl_addr_offset, addr,
        bind_ack->dl_addr_length);
    return 0;
}

/***********************************************************************
 * interface:
 * function mac_addr_dlpi - get the mac address of the interface with 
 *                          type dev (eg lnc, hme) and unit (0, 1 ..)
 *
 * parameter: addr: an array of six bytes, has to be allocated by the caller
 *
 * return: 0 if OK, -1 if the address could not be determined
 *
 *
 ***********************************************************************/

long mac_addr_dlpi( const char *dev, int unit, u_char  *addr) {

	int fd;
	u_char mac_addr[25];

	if (GOT_ERR != dl_open(dev, unit, &fd)) {
        	if (GOT_ERR != dl_bind(fd, INSAP, mac_addr)) {
                	bcopy( mac_addr, addr, 6);
                	return 0;
                }
	}
        close(fd);
	return -1;
}

						/* Kompf 2000-2003 */

#endif

/* print usage help */
void print_help(void){

	print_revision(progname,revision);

	printf(COPYRIGHT, copyright, email);
	
	printf("\n\nThis program checks the existence and more details of a DHCP server\n\n");

	print_usage();

	printf("\
 -s, --serverip=IPADDRESS\n\
   IP address of DHCP server that we must hear from\n\
 -r, --requestedip=IPADDRESS\n\
   IP address that should be offered by at least one DHCP server\n\
 -m, --mac=MACADDRESS\n\
   Client MAC address to use for sending packets\n\
 -b, --bannedip=IPADDRESS\n\
   Server IP address to ignore\n\
 -t, --timeout=INTEGER\n\
   Seconds to wait for DHCPOFFER before timeout occurs\n\
 -i, --interface=STRING\n\
   Interface to to use for listening (i.e. eth0)\n\
 -v, --verbose\n\
   Print extra information (command-line use only)\n\
 -h, --help\n\
   Print detailed help screen\n\
 -V, --version\n\
   Print version information\n\n\
Example: sudo ./dhcpdiscover -i eth0 -b 192.168.1.1\n\
");
}


void print_usage(void)
{
	printf("\
Usage: %s [-s serverip] [-r requestedip] [-m clientmac ] [-b bannedip] [-t timeout] [-i interface]\n\
                  [-v]",progname);
}