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pkg-monitoring-plugins/plugins-root/check_dhcp.c

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/*****************************************************************************
*
* Monitoring check_dhcp plugin
*
* License: GPL
* Copyright (c) 2001-2004 Ethan Galstad (nagios@nagios.org)
* Copyright (c) 2001-2007 Monitoring Plugins Development Team
*
* Description:
*
* This file contains the check_dhcp plugin
*
* This plugin tests the availability of DHCP servers on a network.
*
* Unicast mode was originally implemented by Heiti of Boras Kommun with
* general improvements as well as usability fixes and "forward"-porting by
* Andreas Ericsson of OP5 AB.
*
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*
*****************************************************************************/
const char *progname = "check_dhcp";
const char *copyright = "2001-2023";
const char *email = "devel@monitoring-plugins.org";
#include "common.h"
#include "netutils.h"
#include "utils.h"
#include <ctype.h>
#include <stdio.h>
#include <stdlib.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 HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif // HAVE_SYS_SOCKIO_H
#if defined( __linux__ )
#include <linux/if_ether.h>
#include <features.h>
#elif defined (__bsd__)
#include <netinet/if_ether.h>
#include <sys/param.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
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 // __sun__ || __solaris__ || __hpux
/**** Common definitions ****/
#define OK 0
#define ERROR -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{
uint8_t op; /* packet type */
uint8_t htype; /* type of hardware address for this machine (Ethernet, etc) */
uint8_t hlen; /* length of hardware address (of this machine) */
uint8_t hops; /* hops */
uint32_t xid; /* random transaction id number - chosen by this machine */
uint16_t secs; /* seconds used in timing */
uint16_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 next 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 */
uint32_t lease_time; /* lease time in seconds */
uint32_t renewal_time; /* renewal time in seconds */
uint32_t rebinding_time; /* rebinding time in seconds */
bool desired; /* is this offer desired (necessary in exclusive mode) */
struct dhcp_offer_struct *next;
}dhcp_offer;
typedef struct requested_server_struct{
struct in_addr server_address;
bool answered;
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_SERVER_IDENTIFIER 54
#define DHCP_OPTION_RENEWAL_TIME 58
#define DHCP_OPTION_REBINDING_TIME 59
#define DHCP_OPTION_END 255
#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 */
bool unicast = false; /* unicast mode: mimic a DHCP relay */
bool exclusive = false; /* exclusive mode aka "rogue DHCP server detection" */
struct in_addr my_ip; /* our address (required for relay) */
struct in_addr dhcp_ip; /* server to query (if in unicast mode) */
unsigned char client_hardware_address[MAX_DHCP_CHADDR_LENGTH]="";
unsigned char *user_specified_mac=NULL;
char network_interface_name[IFNAMSIZ]="eth0";
uint32_t packet_xid=0;
uint32_t dhcp_lease_time=0;
uint32_t dhcp_renewal_time=0;
uint32_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;
bool request_specific_address=false;
bool received_requested_address=false;
int verbose=0;
struct in_addr requested_address;
int process_arguments(int, char **);
int call_getopt(int, char **);
int validate_arguments(int);
void print_usage(void);
void print_help(void);
void resolve_host(const char *in,struct in_addr *out);
unsigned char *mac_aton(const char *);
void print_hardware_address(const unsigned char *);
int get_hardware_address(int,char *);
int get_ip_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 = STATE_UNKNOWN;
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
/* Parse extra opts if any */
argv=np_extra_opts(&argc, argv, progname);
if(process_arguments(argc,argv)!=OK){
usage4 (_("Could not parse arguments"));
}
/* create socket for DHCP communications */
dhcp_socket=create_dhcp_socket();
/* get hardware address of client machine */
if(user_specified_mac!=NULL)
memcpy(client_hardware_address,user_specified_mac,6);
else
get_hardware_address(dhcp_socket,network_interface_name);
if(unicast) /* get IP address of client machine */
get_ip_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){
#if defined(__linux__)
struct ifreq ifr;
strncpy((char *)&ifr.ifr_name,interface_name,sizeof(ifr.ifr_name)-1);
ifr.ifr_name[sizeof(ifr.ifr_name)-1]='\0';
/* 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 */
size_t len;
int mib[6];
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;
/* get last number from interfacename, eg lnc0, e1000g0*/
int i;
p = interface_name + strlen(interface_name) -1;
for(i = strlen(interface_name) -1; i > 0; p--) {
if(isalpha(*p))
break;
}
p++;
if( p != interface_name ){
unit = atoi(p) ;
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. Use the --mac option.\n"));
exit(STATE_UNKNOWN);
#endif
if(verbose)
print_hardware_address(client_hardware_address);
return OK;
}
/* determines IP address of the client interface */
int get_ip_address(int sock,char *interface_name){
#if defined(SIOCGIFADDR)
struct ifreq ifr;
strncpy((char *)&ifr.ifr_name,interface_name,sizeof(ifr.ifr_name)-1);
ifr.ifr_name[sizeof(ifr.ifr_name)-1]='\0';
if(ioctl(sock,SIOCGIFADDR,&ifr)<0){
printf(_("Error: Cannot determine IP address of interface %s\n"),
interface_name);
exit(STATE_UNKNOWN);
}
my_ip=((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr;
#else
printf(_("Error: Cannot get interface IP address on this platform.\n"));
exit(STATE_UNKNOWN);
#endif
if(verbose)
printf(_("Pretending to be relay client %s\n"),inet_ntoa(my_ip));
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;
unsigned short opts;
/* 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;
/*
* transaction ID is supposed to be random.
*/
srand(time(NULL)^getpid());
packet_xid=random();
discover_packet.xid=htonl(packet_xid);
/*discover_packet.secs=htons(65535);*/
discover_packet.secs=0xFF;
/*
* server needs to know if it should broadcast or unicast its response:
* 0x8000L == 32768 == 1 << 15 == broadcast, 0 == unicast
*/
discover_packet.flags = unicast ? 0 : 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';
opts = 4;
/* DHCP message type is embedded in options field */
discover_packet.options[opts++]=DHCP_OPTION_MESSAGE_TYPE; /* DHCP message type option identifier */
discover_packet.options[opts++]='\x01'; /* DHCP message option length in bytes */
discover_packet.options[opts++]=DHCPDISCOVER;
/* the IP address we're requesting */
if(request_specific_address){
discover_packet.options[opts++]=DHCP_OPTION_REQUESTED_ADDRESS;
discover_packet.options[opts++]='\x04';
memcpy(&discover_packet.options[opts],&requested_address,sizeof(requested_address));
opts += sizeof(requested_address);
}
discover_packet.options[opts++]= (char)DHCP_OPTION_END;
/* unicast fields */
if(unicast)
discover_packet.giaddr.s_addr = my_ip.s_addr;
/* see RFC 1542, 4.1.1 */
discover_packet.hops = unicast ? 1 : 0;
/* 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 = unicast ? dhcp_ip.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: %u (0x%X)\n",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;
struct sockaddr_in via;
int result=OK;
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(&via,sizeof(via));
bzero(&offer_packet,sizeof(offer_packet));
result=OK;
result=receive_dhcp_packet(&offer_packet,sizeof(offer_packet),sock,dhcpoffer_timeout,&source);
if(result!=OK){
if(verbose)
printf(_("Result=ERROR\n"));
continue;
}
else{
if(verbose)
printf(_("Result=OK\n"));
responses++;
}
/* The "source" is either a server or a relay. */
/* Save a copy of "source" into "via" even if it's via itself */
memcpy(&via,&source,sizeof(source)) ;
if(verbose){
printf(_("DHCPOFFER from IP address %s"),inet_ntoa(source.sin_addr));
printf(_(" via %s\n"),inet_ntoa(via.sin_addr));
printf("DHCPOFFER XID: %u (0x%X)\n",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 (%u) did not match DHCPDISCOVER XID (%u) - ignoring packet\n"),ntohl(offer_packet.xid),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){
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;
fd_set oobfds;
int recv_result;
socklen_t address_size;
struct sockaddr_in source_address;
int nfound;
/* wait for data to arrive (up time timeout) */
tv.tv_sec=timeout;
tv.tv_usec=0;
FD_ZERO(&readfds);
FD_ZERO(&oobfds);
FD_SET(sock,&readfds);
FD_SET(sock,&oobfds);
nfound = select(sock+1,&readfds,NULL,&oobfds,&tv);
/* make sure some data has arrived */
if(!FD_ISSET(sock,&readfds)){
if(verbose)
printf(_("No (more) data received (nfound: %d)\n"), nfound);
return ERROR;
}
else{
bzero(&source_address,sizeof(source_address));
address_size=sizeof(source_address);
recv_result=recvfrom(sock,(char *)buffer,buffer_size,0,(struct sockaddr *)&source_address,&address_size);
if(verbose)
printf("recv_result: %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;
/* listen to DHCP server port if we're in unicast mode */
myname.sin_port = htons(unicast ? DHCP_SERVER_PORT : DHCP_CLIENT_PORT);
myname.sin_addr.s_addr = unicast ? my_ip.s_addr : INADDR_ANY;
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(!unicast && 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-1);
interface.ifr_ifrn.ifrn_name[IFNAMSIZ-1]='\0';
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-1);
interface.ifr_name[IFNAMSIZ-1]='\0';
#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->answered=false;
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;
unsigned option_type;
unsigned option_length;
struct in_addr serv_ident = {0};
if(offer_packet==NULL)
return ERROR;
/* process all DHCP options present in the packet */
for(x=4;x<MAX_DHCP_OPTIONS_LENGTH-1;){
if((int)offer_packet->options[x]==-1)
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 */
switch(option_type){
case DHCP_OPTION_LEASE_TIME:
memcpy(&dhcp_lease_time, &offer_packet->options[x],sizeof(dhcp_lease_time));
dhcp_lease_time = ntohl(dhcp_lease_time);
break;
case DHCP_OPTION_RENEWAL_TIME:
memcpy(&dhcp_renewal_time, &offer_packet->options[x],sizeof(dhcp_renewal_time));
dhcp_renewal_time = ntohl(dhcp_renewal_time);
break;
case DHCP_OPTION_REBINDING_TIME:
memcpy(&dhcp_rebinding_time, &offer_packet->options[x],sizeof(dhcp_rebinding_time));
dhcp_rebinding_time = ntohl(dhcp_rebinding_time);
break;
case DHCP_OPTION_SERVER_IDENTIFIER:
memcpy(&serv_ident.s_addr, &offer_packet->options[x],sizeof(serv_ident.s_addr));
break;
}
/* skip option data we're ignoring */
if(option_type==0) /* "pad" option, see RFC 2132 (3.1) */
x+=1;
else
x+=option_length;
}
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;
/*
* RFC 2131 (2.) says: "DHCP clarifies the interpretation of the
* 'siaddr' field as the address of the server to use in the next step
* of the client's bootstrap process. A DHCP server may return its own
* address in the 'siaddr' field, if the server is prepared to supply
* the next bootstrap service (e.g., delivery of an operating system
* executable image). A DHCP server always returns its own address in
* the 'server identifier' option." 'serv_ident' is the 'server
* identifier' option, 'source' is the IP address we received the
* DHCPOFFER from. If 'serv_ident' isn't available for some reason, we
* use 'source'.
*/
new_offer->server_address=serv_ident.s_addr?serv_ident: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;
new_offer->desired=false; /* exclusive mode: we'll check that in get_results */
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, *undesired_offer=NULL;
requested_server *temp_server;
int result;
uint32_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"),inet_ntoa(temp_server->server_address));
if(temp_server->answered)
printf(_(" (duplicate)"));
printf(_("\n"));
}
if(!temp_server->answered){
requested_responses++;
temp_server->answered=true;
temp_offer->desired=true;
}
}
}
}
/* exclusive mode: check for undesired offers */
for(temp_offer=dhcp_offer_list;temp_offer!=NULL;temp_offer=temp_offer->next) {
if (!temp_offer->desired) {
undesired_offer=temp_offer; /* Checks only for the first undesired offer */
break; /* no further checks needed */
}
}
}
/* 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 && !received_requested_address)
result=STATE_WARNING;
if(exclusive && undesired_offer)
result=STATE_CRITICAL;
if(result==0) /* garrett honeycutt 2005 */
printf("OK: ");
else if(result==1)
printf("WARNING: ");
else if(result==2)
printf("CRITICAL: ");
else if(result==3)
printf("UNKNOWN: ");
/* 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(exclusive && undesired_offer){
printf(_(", Rogue DHCP Server detected! Server %s"),inet_ntoa(undesired_offer->server_address));
printf(_(" offered %s \n"),inet_ntoa(undesired_offer->offered_address));
return result;
}
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)
printf(_(", requested address (%s) was %soffered"),inet_ntoa(requested_address),(received_requested_address)?"":_("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){
if(argc<1)
return ERROR;
call_getopt(argc,argv);
return validate_arguments(argc);
}
int call_getopt(int argc, char **argv){
extern int optind;
int option_index = 0;
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'},
{"unicast", no_argument, 0,'u'},
{"exclusive", no_argument, 0,'x'},
{"verbose", no_argument, 0,'v'},
{"version", no_argument, 0,'V'},
{"help", no_argument, 0,'h'},
{0,0,0,0}
};
int c=0;
while(true){
c=getopt_long(argc,argv,"+hVvxt:s:r:t:i:m:u",long_options,&option_index);
if(c==-1||c==EOF||c==1)
break;
switch(c){
case 's': /* DHCP server address */
resolve_host(optarg,&dhcp_ip);
add_requested_server(dhcp_ip);
break;
case 'r': /* address we are requested from DHCP servers */
resolve_host(optarg,&requested_address);
request_specific_address=true;
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 'm': /* MAC address */
if((user_specified_mac=mac_aton(optarg)) == NULL)
usage("Cannot parse MAC address.\n");
if(verbose)
print_hardware_address(user_specified_mac);
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 'u': /* unicast testing */
unicast=true;
break;
case 'x': /* exclusive testing aka "rogue DHCP server detection" */
exclusive=true;
break;
case 'V': /* version */
print_revision(progname, NP_VERSION);
exit(STATE_UNKNOWN);
case 'h': /* help */
print_help();
exit(STATE_UNKNOWN);
case 'v': /* verbose */
verbose=1;
break;
case '?': /* help */
usage5 ();
break;
default:
break;
}
}
return optind;
}
int validate_arguments(int argc){
if(argc - optind > 0)
usage(_("Got unexpected non-option argument"));
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
/* resolve host name or die (TODO: move this to netutils.c!) */
void resolve_host(const char *in,struct in_addr *out){
struct addrinfo hints, *ai;
memset(&hints,0,sizeof(hints));
hints.ai_family=PF_INET;
if (getaddrinfo(in,NULL,&hints,&ai) != 0)
usage_va(_("Invalid hostname/address - %s"),optarg);
memcpy(out,&((struct sockaddr_in *)ai->ai_addr)->sin_addr,sizeof(*out));
freeaddrinfo(ai);
}
/* parse MAC address string, return 6 bytes (unterminated) or NULL */
unsigned char *mac_aton(const char *string){
static unsigned char result[6];
char tmp[3];
unsigned i, j;
for(i=0, j=0; string[i] != '\0' && j < sizeof(result); i++){
/* ignore ':' and any other non-hex character */
if(!isxdigit(string[i]) || !isxdigit(string[i+1]))
continue;
tmp[0]=string[i];
tmp[1]=string[i+1];
tmp[2]='\0';
result[j]=strtol(tmp,(char **)NULL,16);
i++;
j++;
}
return (j==6) ? result : NULL;
}
void print_hardware_address(const unsigned char *address){
int i;
printf(_("Hardware address: "));
for (i=0; i<5; i++)
printf("%2.2x:", address[i]);
printf("%2.2x", address[i]);
putchar('\n');
}
/* print usage help */
void print_help(void){
print_revision(progname, NP_VERSION);
printf("Copyright (c) 2001-2004 Ethan Galstad (nagios@nagios.org)\n");
printf (COPYRIGHT, copyright, email);
printf("%s\n", _("This plugin tests the availability of DHCP servers on a network."));
printf ("\n\n");
print_usage();
printf (UT_HELP_VRSN);
printf (UT_EXTRA_OPTS);
printf (UT_VERBOSE);
printf (" %s\n", "-s, --serverip=IPADDRESS");
printf (" %s\n", _("IP address of DHCP server that we must hear from"));
printf (" %s\n", "-r, --requestedip=IPADDRESS");
printf (" %s\n", _("IP address that should be offered by at least one DHCP server"));
printf (" %s\n", "-t, --timeout=INTEGER");
printf (" %s\n", _("Seconds to wait for DHCPOFFER before timeout occurs"));
printf (" %s\n", "-i, --interface=STRING");
printf (" %s\n", _("Interface to to use for listening (i.e. eth0)"));
printf (" %s\n", "-m, --mac=STRING");
printf (" %s\n", _("MAC address to use in the DHCP request"));
printf (" %s\n", "-u, --unicast");
printf (" %s\n", _("Unicast testing: mimic a DHCP relay, requires -s"));
printf (" %s\n", "-x, --exclusive");
printf (" %s\n", _("Only requested DHCP server may response (rogue DHCP server detection), requires -s"));
printf (UT_SUPPORT);
return;
}
void
print_usage(void){
printf ("%s\n", _("Usage:"));
printf (" %s [-v] [-u] [-x] [-s serverip] [-r requestedip] [-t timeout]\n",progname);
printf (" [-i interface] [-m mac]\n");
return;
}
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